1
|
Kim S, Ryan Cho H, Kim MO. Predictive generalized varying-coefficient longitudinal model. Stat Med 2021; 40:6243-6259. [PMID: 34494290 DOI: 10.1002/sim.9180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 06/02/2021] [Accepted: 07/29/2021] [Indexed: 11/06/2022]
Abstract
We propose a nonparametric bivariate varying coefficient generalized linear model to predict a mean response trajectory in the future given an individual's characteristics at present or an earlier time point in a longitudinal study. Given the measurement time of the predictors, the coefficients vary as functions of the future time over which the prediction of the mean response is concerned and illustrate the dynamic association between the future response and the earlier measured predictors. We use a nonparametric approach that takes advantage of features of both the kernel and the spline methods for estimation. The resulting coefficient estimator is asymptotically consistent under mild regularity conditions. We also develop a new bootstrap approach to construct simultaneous confidence bands for statistical inference about the coefficients and the predicted response trajectory based on the coverage rate of bootstrap estimates. We use the Framingham Heart Study to illustrate the methodology. The proposed procedure is applied to predict the probability trajectory of hypertension risk given individuals' health condition in early adulthood and to examine the impact of risk factors in early adulthood on a long-term risk of hypertension over several decades.
Collapse
Affiliation(s)
- Seonjin Kim
- Department of Statistics, Miami University, Oxford, Ohio, USA
| | - Hyunkeun Ryan Cho
- Department of Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | - Mi-Ok Kim
- Department of Epidemiology & Biostatistics, University of California, San Francisco, California, USA
| |
Collapse
|
2
|
Guimarães E, Baxter-Jones ADG, Williams AM, Tavares F, Janeira MA, Maia J. Tracking Technical Skill Development in Young Basketball Players: The INEX Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18084094. [PMID: 33924566 PMCID: PMC8070131 DOI: 10.3390/ijerph18084094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 11/16/2022]
Abstract
This study investigated developmental stability, or tracking, in the development of technical skills in youth male basketball players and retrospectively profiled stable and unstable tracking patterns over time. A total of 97 basketball players were tracked bi-annually over 3 consecutive years. Players were divided into two age-categories according to their age at baseline: under-12; and under-14. Technical skills were assessed using the American Alliance for Health, Physical Education, Recreation and Dance test battery. Anthropometric, body composition, biological maturation and physical performance data were collected. Cohen's kappa (κ) was used to estimate tracking. With the exception of defensive movement in the under-12 age-category, tracking was low in all skill tests for both under-12 (0.22 ≤ κ ≤ 0.33) and -14 (0.20 ≤ κ ≤ 0.26) groupings. The overall technical skill showed moderate tracking for under-12 players (κ = 0.47) and low tracking for under-14 players (κ = 0.26). At baseline, players who were consistently more skilled or became more skillful (in the under-12 age-category) over time had a better growth-motor performance profile and most of them were selected to be members of regional teams. In conclusion, tracking of individual skill trajectories was low-to-moderate. Moreover, a better growth-motor performance profile seems crucial to maintain high levels of skill performance over time. It is recommended that basketball coaches track the developmental trajectories of their players to better understand the erratic nature of skill development and help design more effective practice regimes.
Collapse
Affiliation(s)
- Eduardo Guimarães
- Centre of Research, Education, Innovation and Intervention in Sport (CIFI2D), Faculty of Sport, University of Porto, 4200-450 Porto, Portugal; (F.T.); (M.A.J.); (J.M.)
- Correspondence: ; Tel.: +351-220425200
| | | | - A. Mark Williams
- Department of Health and Kinesiology, College of Health, University of Utah, Salt Lake City, UT 84108, USA;
| | - Fernando Tavares
- Centre of Research, Education, Innovation and Intervention in Sport (CIFI2D), Faculty of Sport, University of Porto, 4200-450 Porto, Portugal; (F.T.); (M.A.J.); (J.M.)
| | - Manuel A. Janeira
- Centre of Research, Education, Innovation and Intervention in Sport (CIFI2D), Faculty of Sport, University of Porto, 4200-450 Porto, Portugal; (F.T.); (M.A.J.); (J.M.)
| | - José Maia
- Centre of Research, Education, Innovation and Intervention in Sport (CIFI2D), Faculty of Sport, University of Porto, 4200-450 Porto, Portugal; (F.T.); (M.A.J.); (J.M.)
| |
Collapse
|
3
|
Wu CO, Tian X, Tian L, Reis JP, Zhao L, Allen NB, Bae S, Liu K. Nonparametric estimation of risk tracking indices for longitudinal studies. Stat Methods Med Res 2020; 29:481-497. [PMID: 30945590 PMCID: PMC8674008 DOI: 10.1177/0962280219839427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tracking a subject's risk factors or health status over time is an important objective in long-term epidemiological studies with repeated measurements. An important issue of time-trend tracking is to define appropriate statistical indices to quantitatively measure the tracking abilities of the targeted risk factors or health status over time. We present a number of local and global statistical tracking indices based on the rank-tracking probabilities, which are derived from the conditional distribution functions, and propose a class of kernel-based nonparametric estimation methods. Confidence intervals for the estimators of the tracking indices are constructed through a resampling subject bootstrap procedure. We demonstrate the application of the tracking indices using the body mass index and systolic blood pressure data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. Statistical properties of the estimation methods and bootstrap inference are investigated through a simulation study and an asymptotic development.
Collapse
Affiliation(s)
- Colin O Wu
- Office of Biostatistics Research, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Xin Tian
- Office of Biostatistics Research, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Lu Tian
- Department of Health Research and Policy, Stanford University, Stanford, CA, USA
| | - Jared P Reis
- Division of Cardiovascular Sciences, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Lihui Zhao
- Department of Preventive Medicine, Northwestern Feinberg School of Medicine, Chicago, IL, USA
| | - Norrina B Allen
- Department of Preventive Medicine, Northwestern Feinberg School of Medicine, Chicago, IL, USA
| | - Sejong Bae
- Division of Preventive Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Kiang Liu
- Department of Preventive Medicine, Northwestern Feinberg School of Medicine, Chicago, IL, USA
| |
Collapse
|
4
|
Moreira C, Meira-Machado L, Fonseca MJ, Santos AC. A Multistate Model for Analyzing Transitions Between Body Mass Index Categories During Childhood: The Generation XXI Birth Cohort Study. Am J Epidemiol 2019; 188:305-313. [PMID: 30312367 DOI: 10.1093/aje/kwy232] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 10/04/2018] [Indexed: 12/19/2022] Open
Abstract
Prevalences of overweight and obesity in young children have risen dramatically in the last several decades in most developed countries. Childhood overweight and obesity are known to have immediate and long-term health consequences and are now recognized as important public health concerns. We used a Markov 4-state model with states defined by 4 body mass index (BMI; weight (kg)/height (m)2) categories (underweight (<-2 standard deviations (SDs) of BMI z score), normal weight (-2 ≤ SD ≤ 1), overweight (1 < SD ≤ 2), and obese (>2 SDs of BMI z score)) to study the rates of transition to higher or lower BMI categories among children aged 4-10 years. We also used this model to study the relationships between explanatory variables and their transition rates. The participants consisted of 4,887 children from the Generation XXI Birth Cohort Study (Porto, Portugal; 2005-2017) who underwent anthropometric evaluation at age 4 years and in at least 1 of the subsequent follow-up waves (ages 7 and 10 years). Children who were normal weight were more likely to move to higher BMI categories than to lower categories, whereas overweight children had similar rates of transition to the 2 adjacent categories. We evaluated the associations of maternal age and education, type of delivery, sex, and birth weight with childhood overweight and obesity, but we observed statistically significant results only for sex and maternal education with regard to the progressive transitions.
Collapse
Affiliation(s)
| | - Luís Meira-Machado
- Centre for Molecular and Environmental Biology, University of Minho, Braga, Portugal
- Department of Mathematics and Applications, School of Sciences, University of Minho, Guimarães, Portugal
| | | | - Ana Cristina Santos
- Unidade de Investigação em Epidemiologia
- Departamento de Ciências da Saúde Pública e Forenses e Educação Médica, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| |
Collapse
|
5
|
|
6
|
Henrique RS, Bustamante AV, Freitas DL, Tani G, Katzmarzyk PT, Maia JA. Tracking of gross motor coordination in Portuguese children. J Sports Sci 2017; 36:220-228. [DOI: 10.1080/02640414.2017.1297534] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Rafael S. Henrique
- Higher School of Physical Education, University of Pernambuco, Recife, Brazil
| | - Alcibíades V. Bustamante
- Academic Department of Applied Sciences for Physical Education and Sport, National University of Education Enrique Guzmán y Valle, Lima, Peru
| | - Duarte L. Freitas
- Department of Physical Education and Sport, University of Madeira, Funchal, Portugal
| | - Go Tani
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Peter T. Katzmarzyk
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana, USA
| | - José A. Maia
- CIFI2D, Faculty of Sport, Kinanthropometry Lab, University of Porto, Porto, Portugal
| |
Collapse
|
7
|
Ye C, Pan Y, Xu X, Su S, Snieder H, Treiber F, Kapuku G, Wang X. Pulse wave velocity in elastic and muscular arteries: tracking stability and association with anthropometric and hemodynamic measurements. Hypertens Res 2016; 39:786-791. [PMID: 27334066 DOI: 10.1038/hr.2016.67] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/27/2016] [Accepted: 05/05/2016] [Indexed: 01/26/2023]
Abstract
Pulse wave velocity (PWV) has been used as a measurement for arterial stiffness, a predictor of cardiovascular risk. Tracking describes the stability of a measurement over time. The purpose of this study was to evaluate the tracking stability of carotid-femoral (cfPWV), carotid-radial (crPWV) and carotid-distal (cdPWV) PWV in young adults and their associations with anthropometric and hemodynamic measurements. cfPWV, crPWV and cdPWV were measured by tonometric (SphygmoCor) technique in 531 subjects (aged 23.7±4.9 with 42.9% African Americans and 49.9% females). Out of these subjects, 142 subjects had all these 3 PWV measurements evaluated again during their next visit with an average follow-up time of 2 years. In the tracking analysis on the data from the 142 subjects, cfPWV displayed moderate to relatively high tracking ability (r=0.61, P<0.001), whereas crPWV and cdPWV only displayed low to moderate tracking coefficients (r=0.29 and r=0.36 respectively, P<0.001). In the association test on the data from the 531 subjects, all three PWV measurements showed significant correlations with age and obesity related measurements. cfPWV displayed stronger correlations with these parameters. In addition, all three PWVs showed significant correlations with systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure with the exception that no correlation existed between crPWV and pulse pressure. The higher tracking ability of cfPWV and its higher association with obesity related measurements highlights the importance of using cfPWV compared with crPWV and cdPWV for research and clinical settings.
Collapse
Affiliation(s)
- Chengcheng Ye
- Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
| | - Yue Pan
- Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
| | - Xiaojing Xu
- Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
| | - Shaoyong Su
- Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
| | - Harold Snieder
- Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA.,Department of Epidemiology, University Medical Center Groningen, Groningen, The Netherlands
| | - Frank Treiber
- College of Nursing, Medical University of South Carolina, Charleston, SC, USA
| | - Gaston Kapuku
- Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
| | - Xiaoling Wang
- Department of Pediatrics, Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
| |
Collapse
|
8
|
Buffarini R, Muniz LC, Barros AJD, Araújo CL, Gonçalves H, Menezes AMB, Assunção MCF. Stability and change in fruit and vegetable intake of Brazilian adolescents over a 3-year period: 1993 Pelotas Birth Cohort. Public Health Nutr 2016; 19:386-92. [PMID: 26037788 PMCID: PMC4872521 DOI: 10.1017/s1368980015001664] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 03/14/2014] [Accepted: 04/09/2015] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To assess the stability and changes in fruit and vegetable (FV) consumption over a 3-year period during adolescence in a population-based birth cohort. DESIGN Longitudinal descriptive study. FV consumption was collected in 2008 and 2011/12 using an FFQ. We conducted descriptive analyses of medians to assess the trends in FV intake over time. Stability of FV intake was assessed by percentage of agreement and kappa coefficients. SETTING Pelotas, Rio Grande do Sul, Brazil. SUBJECTS Adolescents from 15 to 18 years of age (n 3915). RESULTS We observed an overall slight decrease in FV consumption during adolescence and also a moderate stability, especially in those with higher socio-economic status (proportion of agreement 38.6% and 40.5% for boys and girls, respectively). About a half of those consuming low levels of FV at 15 years of age still consumed low levels 3 years later. CONCLUSIONS Our results showed that FV consumption presented a moderate stability across a 3-year period during adolescence, especially in those with higher socio-economic status. Given the great proportions of non-communicable diseases such as CVD, diabetes and obesity, knowledge about the patterns of FV consumption during adolescence has implications for health promotion interventions.
Collapse
Affiliation(s)
- Romina Buffarini
- Post-Graduate Program in Epidemiology, Federal University of Pelotas, CP 464, 96001-970 Pelotas, RS, Brazil
| | - Ludmila C Muniz
- Post-Graduate Program in Epidemiology, Federal University of Pelotas, CP 464, 96001-970 Pelotas, RS, Brazil
| | - Aluísio JD Barros
- Post-Graduate Program in Epidemiology, Federal University of Pelotas, CP 464, 96001-970 Pelotas, RS, Brazil
| | - Cora L Araújo
- Post-Graduate Program in Epidemiology, Federal University of Pelotas, CP 464, 96001-970 Pelotas, RS, Brazil
| | - Helen Gonçalves
- Post-Graduate Program in Epidemiology, Federal University of Pelotas, CP 464, 96001-970 Pelotas, RS, Brazil
| | - Ana MB Menezes
- Post-Graduate Program in Epidemiology, Federal University of Pelotas, CP 464, 96001-970 Pelotas, RS, Brazil
| | - Maria CF Assunção
- Department of Nutrition, School of Nutrition, Federal University of Pelotas, Pelotas, RS, Brazil
| |
Collapse
|
9
|
Kelly RK, Magnussen CG. Epidemiology of elevated blood pressure in youth and its utility for predicting adulthood outcomes: A review. World J Hypertens 2014; 4:29-36. [DOI: 10.5494/wjh.v4.i4.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 08/29/2014] [Accepted: 10/16/2014] [Indexed: 02/06/2023] Open
Abstract
Elevated blood pressure has been demonstrated to track from youth to adulthood and some have demonstrated an association between early-life blood pressure and subsequent atherosclerosis and cardiovascular disease. In addition, reports regarding the strength of tracking are inconsistent and the modifiable risk factors that affect the trajectory of blood pressure from youth to adulthood remain unclear. This paper comprehensively evaluated the existing classifications of youth hypertension and the current trends of youth hypertension. Further, evidence for the consequences of hypertension in youth has been comprehensively evaluated. Importantly, a review of the studies examining tracking from youth to adulthood has been performed and a number of studies investigating the factors affecting tracking has also been investigated. The overall consideration of this body of literature highlights the vital importance of identifying hypertension in youth to prevent complications in adulthood. Adiposity is regarded to be a factor affecting the progression of hypertension from youth to adulthood yet there is little evidence available for other modifiable factors. It is apparent that further research is necessary within this field in order to create effective preventative strategies to target youth hypertension.
Collapse
|
10
|
Silva SPD, Beunen G, Prista A, Maia J. Short-term tracking of performance and health-related physical fitness in girls: The Healthy Growth in Cariri Study. J Sports Sci 2013; 31:104-13. [DOI: 10.1080/02640414.2012.723817] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
11
|
Affiliation(s)
- J. M. G. Taylor
- a Department of Biostatistics , University of California , Los Angeles , CA , 90024-1772
| | - W. G. Cumberland
- a Department of Biostatistics , University of California , Los Angeles , CA , 90024-1772
| | - J. P. Sy
- a Department of Biostatistics , University of California , Los Angeles , CA , 90024-1772
| |
Collapse
|
12
|
A 15-year longitudinal study on ambulatory blood pressure tracking from childhood to early adulthood. Hypertens Res 2009; 32:404-10. [PMID: 19325561 DOI: 10.1038/hr.2009.32] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study evaluates the tracking stability of office blood pressure (BP), ambulatory BP (ABP), BP variability (BPV) and nocturnal BP drops (dipping) from childhood to early adulthood, and their dependence on ethnicity, gender and family history (FH) of essential hypertension (EH). Generalized estimating equations (GEEs) were used to estimate tracking coefficients for 295 European Americans and 252 African Americans, with a maximum of 12 measurements over a 15-year period. Office BP and ABP had moderate-to-relatively high tracking coefficients (r= 0.30-0.59; P<or=0.001). Twenty-four hour readings tracked better than office readings for diastolic BP (DBP; 0.57 vs. 0.46, P=1.72 x 10(-6)) and pulse pressure (PP) (0.59 vs. 0.51, P=2.70 x 10(-4)), and equally well for systolic BP (SBP; 0.55 vs. 0.54, P=0.805). Daytime readings tracked better than their night-time counterparts for SBP (0.50 vs. 0.37, P=7.62 x 10(-13)), DBP (0.49 vs. 0.30, P=7.98 x 10(-32)) and PP (0.55 vs. 0.50, P=0.0061). All BPV (r=0.08-0.28; P<or=0.001) and dipping measures (r=0.07-0.12; odds ratio, 1.60-1.73; P<or=0.001) had low tracking coefficients. Males had significantly higher tracking stability for office SBP, DBP and ambulatory PP than females (P<0.01). Subjects with a positive FH of EH had significantly higher tracking stability for daytime and night-time DBP and dipping indexed by continuous variables than those with a negative FH (P<0.001). No significant ethnic differences were observed. The high tracking stability of 24-h ABP highlights the importance of using ambulatory BP monitoring in both research and clinical settings.
Collapse
|
13
|
Candel MJ. Optimal designs for empirical bayes estimators of individual linear and quadratic growth curves in linear mixed models. Stat Methods Med Res 2008; 18:397-419. [PMID: 19036913 DOI: 10.1177/0962280207088026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many studies on optimal designs for linear mixed model analysis of repeated measures data have focussed on estimating the fixed effects. The present study investigates the optimal number of time points and subjects in case random effects have to be estimated. Linear mixed models with a linear or quadratic trend across equidistant time points are studied. Given a particular cost function, we examine which designs minimise the expected average squared prediction error. Robustness of the optimal design, important when one does not know the underlying model, is also treated.
Collapse
Affiliation(s)
- Math Jjm Candel
- Department of Methodology and Statistics, Maastricht University, The Netherlands.
| |
Collapse
|
14
|
Singh AS, Mulder C, Twisk JWR, van Mechelen W, Chinapaw MJM. Tracking of childhood overweight into adulthood: a systematic review of the literature. Obes Rev 2008; 9:474-88. [PMID: 18331423 DOI: 10.1111/j.1467-789x.2008.00475.x] [Citation(s) in RCA: 1710] [Impact Index Per Article: 100.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Overweight and obesity in youth are important public health concerns and are of particular interest because of possible long-term associations with adult weight status and morbidity. The aim of this study was to systematically review the literature and update evidence concerning persistence of childhood overweight. A computerized bibliographical search--restricted to studies with a prospective or retrospective longitudinal design--was conducted. Two authors independently extracted data and assessed the methodological quality of the included studies in four dimensions (i) study population and participation rate; (ii) study attrition; (iii) data collection and (iv) data analysis. Conclusions were based on a rating system of three levels of evidence. A total of 25 publications were selected for inclusion in this review. According to a methodological quality assessment, 13 studies were considered to be of high quality. The majority of these high-quality studies were published after 2001, indicating that recently published data, in particular, provide us with reliable information. All included studies consistently report an increased risk of overweight and obese youth becoming overweight adults, suggesting that the likelihood of persistence of overweight into adulthood is moderate for overweight and obese youth. However, predictive values varied considerably. Limiting aspects with respect to generalizability and methodological issues are discussed.
Collapse
Affiliation(s)
- A S Singh
- VU University Medical Center, EMGO Institute, Department of Public and Occupational Health, Amsterdam, the Netherlands.
| | | | | | | | | |
Collapse
|
15
|
|
16
|
Deshmukh-Taskar P, Nicklas TA, Morales M, Yang SJ, Zakeri I, Berenson GS. Tracking of overweight status from childhood to young adulthood: the Bogalusa Heart Study. Eur J Clin Nutr 2006; 60:48-57. [PMID: 16132057 DOI: 10.1038/sj.ejcn.1602266] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To understand tracking of overweight status from childhood to young adulthood in a biracial sample. DESIGN A longitudinal sample was created from cross-sectional surveys at two time points, childhood (baseline) and young adulthood (follow-up). SETTING Bogalusa Heart Study, Louisiana, United States of America. SUBJECTS A total of 841 young adults, 19-35 years (68% Euro-Americans (EA), 32% African-Americans (AA)) were studied. The same subjects had also participated in one of the five cross-sectional surveys at childhood (9-11 years). METHODS Body mass index (BMI) was used to determine overweight status as per the Centers for Disease Control and Prevention standards. Change in the BMI status from childhood to young adulthood was used to group the participants into the following categories: normal weight to normal weight (NW-NW); normal weight to overweight (NW-OW); overweight to normal weight (OW-NW); and overweight to overweight (OW-OW). Tracking of overweight was defined by (1) correlations between baseline and follow-up BMI, (2) Cohen's kappa concordance test to determine the strength of tracking in BMI quartiles and (3) the percentage of individuals who remained in the same overweight status group from baseline to follow-up. RESULTS From baseline to follow-up, the percentage of participants who were overweight increased from 24.7 to 57.7%. A total of 35.2% of the children shifted from normal weight in childhood to overweight in young adulthood (P < 0.0005). Baseline BMI was positively correlated with follow-up BMI (r = 0.66, P < 0.0005). A total of 61.9% of the participants in the highest BMI quartile in childhood remained in the highest BMI quartile in young adulthood. The strength of tracking in BMI quartiles was 27% for EA men (P < 0.0005), 23% for EA women (P < 0.0005), 27% for AA men (P<0.0005) and 35% for AA women (P < 0.0005). A total of 53.7% of the EA women remained in the NW-NW category and 31.2% of the AA women remained in the OW-OW category. The percentage tracking (NW-NW and OW-OW) was 72.8% in EA women, 59.6% in AA men, 59.5% in AA women and 48.8% in EA men (P < 0.0001). CONCLUSION Childhood overweight tracked into young adulthood in this sample and the tracking of NW-NW and OW-OW was the most prominent among the EA women.
Collapse
Affiliation(s)
- P Deshmukh-Taskar
- Department of Pediatrics, Baylor College of Medicine, Children's Nutrition Research Center, Houston, TX 77030, USA
| | | | | | | | | | | |
Collapse
|
17
|
Emaus N, Berntsen GKR, Joakimsen R, Fonnebø V. Longitudinal changes in forearm bone mineral density in women and men aged 45-84 years: the Tromso Study, a population-based study. Am J Epidemiol 2006; 163:441-9. [PMID: 16394202 DOI: 10.1093/aje/kwj055] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to describe changes in bone mineral density in Norwegian women and men aged 45-84 years in a population-based, longitudinal study. Bone mineral density (g/cm2) was measured at distal and ultradistal forearm sites with single x-ray absorptiometric devices in 3,169 women and 2,197 men at baseline in 1994-1995 and at follow-up in 2001 (standard deviation, 0.4 years). The mean annual bone loss was -0.5% and -0.4% in men and -0.9% and -0.8% in women not using hormone replacement therapy at the distal and ultradistal sites, respectively. In men, age was a negative predictor of bone mineral density change at both sites. Women not using hormone replacement therapy had the highest bone loss at the ultradistal site 1-5 years after menopause. The correlation between the two measurements was high: r = 0.93 and r = 0.90 in women and r = 0.96 and r = 0.93 in men for the distal and ultradistal sites, respectively. More than 70% kept their quartile positions, indicating a high degree of tracking of bone mineral density measurements. Although the study population live above the polar circle, the rate of bone loss was not higher at the distal and ultradistal forearm sites compared with that of other cohorts.
Collapse
Affiliation(s)
- N Emaus
- Institute of Community Medicine, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
| | | | | | | |
Collapse
|
18
|
Emaus N, Berntsen GKR, Joakimsen RM, Fønnebø V. Longitudinal changes in forearm bone mineral density in women and men aged 25-44 years: the Tromsø study: a population-based study. Am J Epidemiol 2005; 162:633-43. [PMID: 16120708 DOI: 10.1093/aje/kwi258] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The aim of this study was to describe and compare bone mineral density (BMD) development in Norwegian women and men aged 25-44 years in a population-based, longitudinal study. BMD was measured twice at distal and ultradistal forearm sites by single x-ray absorptiometry in 258 women and 147 men (mean follow-up time, 6.4 (standard deviation, 0.6) years). At the distal site, a small annual gain of approximately 0.1% became a small loss beginning at age 34 years in men and age 36 years in women. At the ultradistal site, BMD change was predicted by age in women only, and bone loss started at age 38 years. A high degree of tracking of BMD measurements was observed for both sexes and both sites, r > 0.93. Depending on total BMD change, participants were grouped into "losers", "nonlosers", and "gainers", and more than 6% lost more than the smallest detectable amount of BMD: > or =3.46% at the distal site and > or =5.14% at the ultradistal site. In both sexes, bone mineral content (grams) decreased, whereas area (centimeters squared) increased significantly in "losers" compared with "gainers". This finding might represent physiologic compensation preserving bone strength. No cohort effects were observed when 1994 and 2001 measures from similar age groups were compared.
Collapse
Affiliation(s)
- N Emaus
- Institute of Community Medicine, Faculty of Medicine, University of Tromsø, Tromsø, Norway.
| | | | | | | |
Collapse
|
19
|
Karlamangla AS, Singer BH, Williams DR, Schwartz JE, Matthews KA, Kiefe CI, Seeman TE. Impact of socioeconomic status on longitudinal accumulation of cardiovascular risk in young adults: the CARDIA Study (USA). Soc Sci Med 2005; 60:999-1015. [PMID: 15589670 DOI: 10.1016/j.socscimed.2004.06.056] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Our objectives were to describe the trajectories of biological risk factors of cardiovascular disease in young adults, and to study the association of socioeconomic status (SES) with aggregate risk scores that summarize longitudinal risk accumulation from multiple risk factors. We used data from a prospective, bi-racial, cohort study of 18-30-year-old adults in the USA, initiated in 1985, with 10-year follow-up. SES was measured by parental education level, financial hardship during the study, and the participant's education level by the end of the study. We studied growth patterns of seven biological risk factors for cardiovascular disease using a semi-parametric, class-mixture model to identify clusters of individuals with distinct growth trajectories. Risk scores that summarize risk from all seven risk factors were created to reflect risk at baseline, longitudinal risk change over 10 years, and total accumulated risk. Multivariable regression was used to study their associations with SES within each race/gender group. We found tracking of all seven risk factors: in each case, the cluster with the highest baseline value maintained its position as the highest-risk cluster over the next 10 years. After adjustment for age, lifestyle, and healthcare access, SES was associated inversely with baseline risk score in women (black and white), with risk change score in all four race/gender groups, and with accumulated risk score in women (black and white) and in white men. Our findings suggest that individuals with high overall cardiovascular risk in midlife can be identified by their relatively higher values of risk factors in younger ages and that socioeconomic differences in cardiovascular risk start accumulating early in life.
Collapse
Affiliation(s)
- Arun S Karlamangla
- Division of Geriatrics, UCLA School of Medicine, 10945 Le Conte #2339, Los Angeles, CA 90095-1687, USA.
| | | | | | | | | | | | | |
Collapse
|
20
|
Bingenheimer JB, Raudenbush SW. Statistical and Substantive Inferences in Public Health: Issues in the Application of Multilevel Models. Annu Rev Public Health 2004; 25:53-77. [PMID: 15015912 DOI: 10.1146/annurev.publhealth.25.050503.153925] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Multilevel statistical models have become increasingly popular among public health researchers over the past decade. Yet the enthusiasm with which these models are being adopted may obscure rather than solve some problems of statistical and substantive inference. We discuss the three most common applications of multilevel models in public health: (a) cluster-randomized trials, (b) observational studies of the multilevel etiology of health and disease, and (c) assessments of health care provider performance. In each area of investigation, we describe how multilevel models are being applied, comment on the validity of the statistical and substantive inferences being drawn, and suggest ways in which the strengths of multilevel models might be more fully exploited. We conclude with a call for more careful thinking about multilevel causal inference.
Collapse
|
21
|
Abstract
One of the purposes of monitoring a child's weight or height is to detect growth faltering. In infancy the focus is on monitoring weight gain, primarily for detecting infants at risk of failure-to-thrive. In childhood, this switches to height gain, e.g. the response of a child that is growth hormone deficient to treatment with growth hormone. Cross-sectional charts provide no guidance in a longitudinal context. If we note the current weight or height of a child, but want to say something about a child's growth since the last weight and height measurement, we need to use a velocity/increment reference or take a conditional approach to the problem. Here we focus on growth faltering and review the mathematical approaches to this problem. Discussion will concentrate on the relative merits of the following approaches: velocity references and increment charts or tables; conditional gain Z-scores;infancy weight-monitoring charts and longitudinal growth norms implemented in the growth package LGROW; tracking indices and distance charts and centile crossing. Overall conditional gain Z-scores provide the most flexible means of assessing growth patterns.
Collapse
Affiliation(s)
- J Argyle
- Department of Mathematical Sciences, University of Durham, UK.
| |
Collapse
|
22
|
Zive MM, Berry CC, Sallis JF, Frank GC, Nader PR. Tracking dietary intake in white and Mexican-American children from age 4 to 12 years. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 2002; 102:683-9. [PMID: 12008994 DOI: 10.1016/s0002-8223(02)90155-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To examine the tracking (ie, the stability over time) of dietary intake in Mexican-American and white children aged 4 to 12 years. SUBJECTS Children 4 years of age (n=351) were assessed at baseline and 65% (n=228) completed the 8-year study. DESIGN Cardiovascular disease-related dietary intake was defined as energy, percent of energy from fat, and sodium (mg/1,000 kcal). From age 4 to 7 years, a modified 24-hour recall with observation of lunch and dinner and interview of the primary food preparer for unobserved foods was used to describe dietary intake. For children aged 11 to 12 years, a standardized 24-hour recall was used. STATISTICAL ANALYSES A mixed effects model that adjusted for sex, ethnicity, and measurement wave allowed for separation of shorter-term variations in diet from more stable ("between subject") variations. Extent of between-subject variance is an indication of tracking. RESULTS From age 4 to age 7, there were statistically significant between-subject variance components for energy (P<.00001), percent of energy from fat (P<.00001), and sodium per 1,000 kcals (P<.001); for ages 11 and 12, energy intake was significant (P<.00001). There were no significant associations for dietary intake from age 4 to 12 years. CONCLUSIONS/APPLICATIONS It seems that dietary intakes are stable over short periods and at earlier ages compared with longer intervals and later ages. Nutrition interventions are needed in childhood and throughout adolescence.
Collapse
Affiliation(s)
- Michelle Murphy Zive
- Community Pediatrics Division, University of California, San Diego, La Jolla 92093-0927, USA
| | | | | | | | | |
Collapse
|
23
|
Guo SS, Chumlea WC. Tracking of body mass index in children in relation to overweight in adulthood. Am J Clin Nutr 1999; 70:145S-8S. [PMID: 10419418 DOI: 10.1093/ajcn/70.1.145s] [Citation(s) in RCA: 360] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Body mass index (BMI; in kg/m2) values at or above the 75th percentile are associated with increased morbidity and mortality in adulthood, and there are significant correlations between BMI values in childhood and in adulthood. The present study addresses the predictive value of childhood BMI for overweight at 35 +/- 5 y, defined as BMI >28 for men and BMI >26 for women. Analyses of data from 555 white children showed that overweight at age 35 y could be predicted from BMI at younger ages. The prediction is excellent at age 18 y, good at age 13 y, but only moderate at ages <13 y. For 18-y-olds with BMIs above the 60th percentile, the probability of overweight at age 35 y is 34% for men and 37% for women. A clinically applicable method is provided to assign an overweight child to a group with a known probability of high BMI values in adulthood.
Collapse
Affiliation(s)
- S S Guo
- Division of Human Biology, Departmentof Community Health Pediatrics, Wright State University School of Medicine, Yellow Springs, OH 45387-1695, USA.
| | | |
Collapse
|
24
|
Schneiderman ED, Kowalski CJ. Analysis of longitudinal data in craniofacial research: some strategies. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1994; 5:187-202. [PMID: 7703322 DOI: 10.1177/10454411940050030101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Although it is generally acknowledged that longitudinal data provide the most information on growth and development and other time-dependent phenomena, such data are often analyzed by conventional (cross-sectional) statistical methods. This widespread practice ignores the distinctive characteristics (e.g., covariance structure) of longitudinal data and may yield misleading results. The purpose of this article is to present some strategies and make available computer programs for the appropriate analysis of longitudinal data. User-friendly PC programs for the estimation of average growth curves, computation of tracking indices, prediction of future values, diagnosis, classification, clustering, estimation of missing values, and testing hypotheses concerning individual and group differences are presented. Benefits of these methods over the usual techniques are illustrated with the example of maxillary growth in the rhesus monkey.
Collapse
Affiliation(s)
- E D Schneiderman
- Department of Oral and Maxillofacial Surgery, Baylor College of Dentistry, Dallas, TX 75266-0677, USA
| | | |
Collapse
|
25
|
Furey AM, Kowalski CJ, Schneiderman ED, Willis SM. GTRACK: a PC program for computing Goldstein's growth constancy index and an alternative measure of tracking. INTERNATIONAL JOURNAL OF BIO-MEDICAL COMPUTING 1994; 36:311-8. [PMID: 8002106 DOI: 10.1016/0020-7101(94)90085-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This paper reviews Goldstein's 'growth constancy index,' Xi, a measure of tracking which can be used to determine whether or not individuals maintain their relative positions in the distribution of a given measurement as that distribution changes over time. We suggest that Xi is an appropriate measure of tracking when the (standardized) measurements arise in the context of a Model I ANOVA, but that the intraclass correlation coefficient, rI, may be preferred when a Model II ANOVA is applicable. We also describe--and make available--a PC program which allows the user to choose between Model I and Model II, and computes the appropriate tracking index and confidence intervals for the corresponding parameter.
Collapse
Affiliation(s)
- A M Furey
- Department of Biostatistics, University of Michigan, Ann Arbor 48109
| | | | | | | |
Collapse
|
26
|
Guo IY, Schneiderman ED, Kowalski CJ, Willis SM. PC program for growth prediction in the two-stage polynomial growth curve model. INTERNATIONAL JOURNAL OF BIO-MEDICAL COMPUTING 1994; 35:39-46. [PMID: 8175207 DOI: 10.1016/0020-7101(94)90047-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We consider the problem of growth prediction in the context of the two-stage (or random coefficients) one-sample polynomial growth curve model and provide a PC program, written in GAUSS386i, to perform the associated computations. The problem considered is that of estimating the value of the measurement under consideration for a 'new' individual at the Tth time point given measurements on that individual at T-1 previous points in time and the values of the measurement on N 'similar' individuals at all T time points. The times of measurement t1, t2, ..., tT need not be equally spaced, but we assume that each of the N individuals comprising the normative sample were measured at these times. The method and the program are illustrated using the data set previously considered (Schneiderman and Kowalski, Am J Phys Anthrop, 67 (1985) 323-333) consisting of mandibular ramus height measurements (in mm) for 12 male rhesus monkeys at T = 5 yearly intervals (coded 1, 2, 3, 4, and 5). Results are compared with those obtained under a less restrictive set of assumptions concerning the covariance matrix of the observations than is made in the context of the two-stage model. It is seen that the accuracies of prediction of the two methods, for this and other data sets, are quite close, suggesting that the less restrictive model may be preferred in many situations.
Collapse
Affiliation(s)
- I Y Guo
- Department of Public Health Sciences, Baylor College of Dentistry, Dallas, TX 75246
| | | | | | | |
Collapse
|
27
|
Abstract
Epidemiologists have used the term 'tracking' to connote an individual's maintenance of relative rank of some longitudinally measured characteristic over a given time span. To assess the extent to which an attribute tracks we have first to summarize individual growth curves, and second to quantify the notion of maintenance of relative rank, both in the face of random error. A sequence of papers appearing in 1981 provided differing methodologies for appraising tracking. Here we take a different approach to tracking by using regression trees for longitudinal data. The above two concerns are simultaneously addressed in that the procedure identifies subgroups, defined in terms of covariates, within which the collection of growth curves is homogeneous. After reviewing the existing approaches to tracking we describe the tree-structured methodology, and present an illustrative example pertaining to lung function growth in children.
Collapse
Affiliation(s)
- M R Segal
- Division of Biostatistics, University of California, San Francisco 94143-0560
| | | |
Collapse
|
28
|
Abstract
Recommendations are made for strengthening data description and analysis in craniofacial biology. Special emphasis is placed on longitudinal data, and PC programs for accomplishing appropriate analyses in this context are described and made available to interested readers. Some more general recommendations are treated in less detail. These include the effective description of data using stem-and-leaf displays and/or boxplots, the use of decision-analytic methods in the management of patients with dentofacial deformities, and the valid application of certain statistical methods in single-subject studies. Finally, it is conjectured that computer-intensive methods such as randomization tests and jackknifing will play an increasingly prominent role in craniofacial research.
Collapse
Affiliation(s)
- C J Kowalski
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor 48109
| |
Collapse
|
29
|
|
30
|
|
31
|
Grobbee DE. Predicting hypertension in childhood: value of blood pressure measurement and family history. J Am Coll Nutr 1992; 11 Suppl:55S-59S. [PMID: 1619201 DOI: 10.1080/07315724.1992.10737985] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An elevated casual blood pressure (BP) in children and a positive family history for hypertension are risk indicators for adult hypertension. The risk of future hypertension is higher when BP levels in children or their parents are higher. Using multiple BP readings in children and their parents, groups of children can be discriminated with contrasting risks as a basis for studying the early phase of primary hypertension. Yet, as a means of detecting groups of children eligible for intervention, family history and BP level lack sensitivity for adequate selection. Before screening for future hypertension may be initiated successfully in prepubertal children, more should be known about the determinants and etiology of future BP rise.
Collapse
Affiliation(s)
- D E Grobbee
- Department of Epidemiology and Biostatistics, Erasmus University Medical School, Rotterdam, The Netherlands
| |
Collapse
|
32
|
Schneiderman ED, Willis SM, Kowalski CJ, Ten Have TR. A PC program for growth prediction in the context of Rao's polynomial growth curve model. Comput Biol Med 1992; 22:181-8. [PMID: 1617952 DOI: 10.1016/0010-4825(92)90014-e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We consider the problem of growth prediction in the context of Rao's [1] one-sample polynomial growth curve model and provide a PC program, written in GAUSS, to perform the associated computations. Specifically, the problem considered is that of estimating the value of the measurement under consideration for a "new" individual at the Tth time point given measurements on that individual at T-1 previous points in time and the values of the measurement on N "similar" individuals at all T time points. The times of measurement t1, t2, . . ., tT need not be equally spaced, but we assume that each of the N individuals comprising the normative sample were measured at these times. The method and the program are illustrated using the leave-one-out method on a sample of N = 12 male rhesus monkeys whose mandibular ramus height was measured five times at yearly intervals.
Collapse
Affiliation(s)
- E D Schneiderman
- Department of Oral and Maxillofacial Surgery, Baylor College of Dentistry, Dallas, TX 75246
| | | | | | | |
Collapse
|
33
|
Schneiderman ED, Kowalski CJ, Ten Have TR, Willis SM. Computation of Foulkes and Davis' nonparametric tracking index using GAUSS. Am J Hum Biol 1992; 4:417-420. [DOI: 10.1002/ajhb.1310040318] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/1990] [Accepted: 09/19/1991] [Indexed: 11/11/2022] Open
|
34
|
Ten Have TR, Kowalski CJ, Schneiderman ED. PC program for obtaining orthogonal polynomial regression coefficients for use in longitudinal data analysis. Am J Hum Biol 1992; 4:403-416. [DOI: 10.1002/ajhb.1310040317] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/1990] [Accepted: 09/09/1991] [Indexed: 11/05/2022] Open
|
35
|
Wong FL, Kodama K, Sasaki H, Yamada M, Hamilton HB. Longitudinal study of the association between ABO phenotype and total serum cholesterol level in a Japanese cohort. Genet Epidemiol 1992; 9:405-18. [PMID: 1487138 DOI: 10.1002/gepi.1370090604] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The relationship between ABO blood phenotype and total serum cholesterol (TC) level was examined in a Japanese population to determine whether an elevated TC level is associated with phenotype A, as has been demonstrated in many West European populations. Such studies in nonwhite populations are scarce, and findings generally failed to demonstrate the relationship. Inconsistent results from cross-sectional studies of various racial groups with widely varying ages raised an age effect as a possible explanatory factor. It was also suggested that the ABO-TC association may not be apparent in populations with low fat intake or low mean cholesterol level. These hypotheses are addressed by examining long-term TC data collected serially from the unexposed controls of the atomic bomb survivors in Hiroshima and Nagasaki who were participants of the Adult Health Study program at the Atomic Bomb Casualty Commission-Radiation Effects Research Foundation between 1958 and 1986. The statistical method of growth curve analysis, through the mixed effect model of Laird and Ware [1982], was used to model age-dependent changes in cholesterol levels within individuals. The effects of the ABO polymorphism in modifying the resultant growth curve are examined. We demonstrate that TC levels are elevated on average by about 4 mg/dl in phenotype A compared to non-A in the Japanese (P < 0.00001), and that this relationship is maintained from early to late adulthood, independent of sex, body mass index, cohort status, or city of residence. Thus, phenotype A individuals may be more predisposed to cardiovascular disease through one of its major risk factors. This is the first study of the ABO-cholesterol association in the Japanese, and the first based on a cohort with longitudinally collected TC data.
Collapse
Affiliation(s)
- F L Wong
- Department of Statistics, Radiation Effects Research Foundation, Hiroshima, Japan
| | | | | | | | | |
Collapse
|
36
|
Rosner B, Muñoz A. A cautionary note on the use of autoregressive models in analysis of longitudinal data. Stat Med 1991; 10:492-5. [PMID: 2028132 DOI: 10.1002/sim.4780100322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
37
|
Have TRT, Kowalski CJ, Schneiderman ED. PC program for analyzing one-sample longitudinal data sets which satisfy the two-stage polynomial growth curve model. Am J Hum Biol 1991; 3:269-279. [DOI: 10.1002/ajhb.1310030306] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/1990] [Accepted: 02/13/1991] [Indexed: 11/08/2022] Open
|
38
|
Schneiderman ED, Kowalski CJ, Have TRT. A GAUSS program for computing an index of tracking from longitudinal observations. Am J Hum Biol 1990; 2:475-490. [PMID: 28520192 DOI: 10.1002/ajhb.1310020504] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/1989] [Accepted: 03/19/1990] [Indexed: 11/06/2022] Open
Abstract
Tracking can be defined as the tendency of individuals or collections of individuals to stay within a particular course of growth over time relative to other individuals. Thus, tracking describes stability in growth patterns. This paper outlines a statistical procedure for examining tracking in a single sample of measurements made on humans or other animals. This nonparametric procedure, based on Cohen's (1960) kappa statistic, is suitable for equally or unequally spaced serial data that is complete and is appropriate for questions concerning growth as well as other time-dependent phenomena. It is a conceptually simple longitudinal method that affords insight regarding the predictability of growth within a population. For example, by tracking, one can ask if young children who are in the lowest height for age category are likely to end up in that category at an older age. A user-friendly GAUSS program is provided that generates overall as well as individual and track-specific statistics. High-resolution graphic representations of the data are also generated by the program. Examples are presented, including a tracking analysis of Guatemalan Indian children using quartiles.
Collapse
Affiliation(s)
- Emet D Schneiderman
- Department of Oral and Maxillofacial Surgery, Baylor College of Dentistry, Dallas, Texas, 75246
| | - Charles J Kowalski
- Department of Oral Biology, The University of Michigan, Ann Arbor, 48109
| | - Thomas R Ten Have
- Department of Biostatistics, The University of Michigan, Ann Arbor, 48109
| |
Collapse
|
39
|
Hibbert ME, Hudson IL, Lanigan A, Landau LI, Phelan PD. Tracking of lung function in healthy children and adolescents. Pediatr Pulmonol 1990; 8:172-7. [PMID: 2349010 DOI: 10.1002/ppul.1950080308] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Two hundred twenty-six healthy school children, with a mean age of 8.8 years; 62 girls mean age 8.8, 48 boys mean age 12.6 and 51 girls mean age 12.6 years at the start, were enrolled in a longitudinal study of lung function and tested annually for 5 years. All were free of respiratory symptoms, and none smoked more than five cigarettes per week during the 5 years. Static and dynamic lung volumes (other than residual volume), maximum expiratory and inspiratory flows, and maximum mouth pressures "track," that is, individuals remain at a constant deviation from the sample mean over time. The data indicate that these measurements of lung function in healthy individuals grow in constant proportion relative to other healthy children and adolescents.
Collapse
Affiliation(s)
- M E Hibbert
- Department of Thoracic Medicine, Royal Children's Hospital, Melbourne, Australia
| | | | | | | | | |
Collapse
|
40
|
Helms RW. Longitudinal designs and their statistical analysis in pediatric pulmonary research. Pediatr Pulmonol 1990; 9:69-71. [PMID: 2399049 DOI: 10.1002/ppul.1950090202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- R W Helms
- Department of Biostatistics, University of North Carolina, Chapel Hill 27599-7400
| |
Collapse
|
41
|
The Management of the Family at High Risk for Coronary Heart Disease. Cardiol Clin 1989. [DOI: 10.1016/s0733-8651(18)30449-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
42
|
Abstract
This paper describes a program that calculates the Foulkes-Davis tracking index, the probability that two individuals selected at random will have measurement curves that do not cross.
Collapse
Affiliation(s)
- G E Dallal
- USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111
| |
Collapse
|
43
|
Schluchter MD. Analysis of incomplete multivariate data using linear models with structured covariance matrices. Stat Med 1988; 7:317-24. [PMID: 3353610 DOI: 10.1002/sim.4780070132] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Incomplete and unbalanced multivariate data often arise in longitudinal studies due to missing or unequally-timed repeated measurements and/or the presence of time-varying covariates. A general approach to analysing such data is through maximum likelihood analysis using a linear model for the expected responses, and structural models for the within-subject covariances. Two important advantages of this approach are: (1) the generality of the model allows the analyst to consider a wider range of models than were previously possible using classical methods developed for balanced and complete data, and (2) maximum likelihood estimates obtained from incomplete data are often preferable to other estimates such as those obtained from complete cases from the standpoint of bias and efficiency. A variety of applications of the model are discussed, including univariate and multivariate analysis of incomplete repeated measures data, analysis of growth curves with missing data using random effects and time-series models, and applications to unbalanced longitudinal data.
Collapse
Affiliation(s)
- M D Schluchter
- Department of Epidemiology and Biostatistics, University of South Carolina, Columbia 29208
| |
Collapse
|
44
|
Abstract
The first part of this paper describes how a Kalman filter can be used to construct maximum likelihood (ML) estimates of autoregressive (AR) and polynomial parameters in polynomial growth curves with AR-1 errors and irregularly-spaced data. The second part introduces a disturbed highest derivative polynomial (DHDP) as a model for growth curves. This model does not depend on regression coefficients. Variances of the highest derivative disturbance and the observation error are estimated (by ML) using a Kalman filter. The estimated DHDP growth curve is obtained by optimally smoothing the output of the filter. Equally spaced data is not required. The DHDP model and analysis are developed for an individual and extended to a population growth curve using data from many individuals with covariates.
Collapse
Affiliation(s)
- P D Wilson
- Department of Epidemiology & Preventive Medicine, University of Maryland, School of Medicine, Baltimore 21201
| |
Collapse
|
45
|
Abstract
Four thousand three hundred and thirteen children beginning at five to fourteen years of age have been examined on three to six occasions in Muscatine, Iowa, on alternate years. To compare blood pressures throughout the period of observation each value was expressed as a percentile rank. For each subject the average percentile rank (level), the trend in rank and the variability over time were calculated. Values for height, weight, relative weight and triceps skinfold thickness measurements were expressed in the same fashion. There is a relationship between average rank of blood pressure and average rank of body size as well as between trend of blood pressure and trend of body size percentiles. These observations indicate the importance of relative rate of growth in the establishment of the rank order of blood pressure during childhood.
Collapse
Affiliation(s)
- R M Lauer
- Department of Pediatrics, University of Iowa, Iowa City 52242
| | | |
Collapse
|
46
|
Michels VV, Bergstralh EJ, Hoverman VR, O'Fallon WM, Weidman WH. Tracking and prediction of blood pressure in children. Mayo Clin Proc 1987; 62:875-81. [PMID: 3657303 DOI: 10.1016/s0025-6196(12)65041-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A significant but weak correlation between an initial and a subsequent blood pressure measurement in the same patient has been found in several previous longitudinal studies of blood pressure in children. In the current study, single determinations of blood pressure, weight, and height were recorded in 142 children at 5.9 to 9.5 years of age and again 9 years later. Both examinations were performed in a schoolroom. Body size at the first examination was associated with body size 9 years later. A significant correlation was noted between initial and subsequent raw systolic blood pressures (r = 0.36 in boys and in girls; P less than 0.01). Correlations of systolic blood pressure based on percentiles for age and for height and weight were smaller but also statistically significant. Correlations involving diastolic blood pressure, with use of raw blood pressure measurements, were significant only for boys (r = 0.24, P less than 0.05). Correlations were not improved when indices of body size were used. Single blood pressure measurements obtained under the usual conditions in a schoolroom had only slightly weaker correlations with subsequent blood pressure determinations than those obtained in studies in which considerable care was taken to achieve more "basal" measurements. This degree of blood pressure correlation is insufficient to allow accurate prediction of subsequent blood pressure levels on the basis of a single casual blood pressure measurement in an individual child. This result was indicated by a wide 95% confidence interval for the predicted subsequent systolic blood pressure, even when sex, initial diastolic blood pressure, weight, and change in weight were considered.
Collapse
Affiliation(s)
- V V Michels
- Department of Medical Genetics, Mayo Clinic, Rochester, MN 55905
| | | | | | | | | |
Collapse
|
47
|
Madsen KS, Miller JP, Province MA. The use of an extended baseline period in the evaluation of treatment in a longitudinal Duchenne muscular dystrophy trial. Stat Med 1986; 5:231-41. [PMID: 3526500 DOI: 10.1002/sim.4780050304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A trial of Duchenne muscular dystrophy involved tracking boys of all ages through a one-year baseline period, followed by a one-year trial of leucine versus placebo treatment. In this paper we develop a model for a total-muscle-strength score that uses the data of the extended baseline period in the evaluation of the leucine treatment. The model is based on a polynomial growth curve in age whose coefficients can vary according to treatment or phase. Maximum likelihood estimates of the parameters of the model are obtained from use of the EM algorithm. We propose tests for the adequacy of the model as well as for treatment effects. A quadratic model appears the most parsimonious fit to the data and there is no evidence of any leucine effect on scores. We examine the asymptotic power of the test for treatment effect and compare it with that of a simpler analysis.
Collapse
|
48
|
Lauer RM, Mahoney LT, Clarke WR. Tracking of blood pressure during childhood: the Muscatine Study. CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1986; 8:515-37. [PMID: 3757274 DOI: 10.3109/10641968609046568] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Four thousand three hundred and thirteen children beginning at five to fourteen years of age have been examined on three to six occasions in Muscatine, Iowa on alternate years. To compare blood pressures throughout the period of observation each value was expressed as a percentile rank. For each subject the average percentile rank (level), the trend in rank and the variability over time were calculated. Values for height, weight, relative weight and triceps skinfold thickness measurements were expressed in the same fashion. The relationship between average rank of blood pressure and average rank of body size as well as between trend of blood pressure and trend of body size percentiles were significant (p less than .05). These observations indicate the importance of relative rate of growth in the establishment of the rank order of blood pressure.
Collapse
|
49
|
Lauer RM, Clarke WR, Beaglehole R. Level, trend, and variability of blood pressure during childhood: the Muscatine study. Circulation 1984; 69:242-9. [PMID: 6690097 DOI: 10.1161/01.cir.69.2.242] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
On alternate years from 1970 to 1981 blood pressure has been measured in school children living in Muscatine, Iowa. A total of 4313 children beginning at 5 to 14 years of age have been examined on three to six occasions. To compare blood pressures throughout the period of observation, each value was expressed as a percentile rank. For each subject the average percentile rank (level), the trend in rank, and the variability over time were calculated. Values for height, weight, relative weight, and triceps skinfold thickness were expressed in the same fashion. The relationship between average rank of blood pressure and average rank of body size as well as between trend of blood pressure and trend of body size percentiles were significant (p less than .05). These observations indicate the importance of relative rate of growth in the establishment of the rank order of blood pressure. Using the variables of level, trend, and variability, we identified groups of children who appear to be consistently tracking toward future hypertension: 233 (5.4%) children, whose systolic levels were in the upper quintile with either a flat or rising trend and low variability, and 280 (6.0%) children with systolic levels in the lower four quintiles with high trend and low variability. In addition there were 321 (7.4%) children whose mean systolic levels were in the upper quintile with high variability and who thus resemble adults with labile hypertension. There were similar numbers of children with diastolic pressures showing these features.
Collapse
|
50
|
|