Meta-Analysis
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©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Meta-Anal. Sep 18, 2023; 11(6): 290-312
Published online Sep 18, 2023. doi: 10.13105/wjma.v11.i6.290
Table 1 Details of the 10 studies of acute myocardial infarction
Study IDa Ref. Country Design Study population Start year Yr followed Age Sexb Cases Adjustc Excld Latencye Endpoint NRRf BIOBANK [37 ] United Kingdom Cohort National 2006 12 40-69 M, F 5081 2 0 0 Diagnosed 2 CaCHS [38 ] Canada Cohort Regional 2001 13 20+ M, F 1133 15 0 0 Diagnosed 2 CALIBER [39 ] United Kingdom Cohort GP records 1997 13 30+ F 5628 1 0 0 Diagnosed 1 EPIC-GERM [40 ] Germany Cohort Regional 1994 14 35-65 C 507 0, 9 0 0 Diagnosed 2 ESTONGENOME [41 ] Estonia Cohort National 2002 13 18+ M, F 118 0, 1 0 0 Died 4g KIHD [42 ] Finland Cohort Regional 1984 18 42-60 M 205 0 0 0 Diagnosed 1 TROMSO [43 ] Norway Cohort Regional 1979 33 20-94 F 854 0, 4 0 0 Diagnosed 2 VASTERBOTTEN [44 ] Sweden Cohort Regional 1990 19 30-60 C 2062 2, 9 0 0 Diagnosed 2 WHILA [45 ] Sweden Cohort Regional 1995 20 50-59 F 205 1, 7 0 0 Diagnosed 2 WHS [46 ] United States Cohort National 1992 26 45+ F 629 0, 14 0 0 Diagnosed 2
Table 2 Details of the 23 studies of ischaemic heart disease
Study IDa Ref. Country Design Study population Start year Yr followed Ageb Sexc Casesd Adjuste Exclf Latencyg Endpoint NRRh 7CNTRY-ITALY [47 ] Italy Cohort Regional 1960 50 40-59 M 319 3 0 0 Died 1 ARIC [48 ] United States Cohort National 1987 30 45-64 C 1798 0, 15 0 0 Diagnosed 2 BIOBANK [49 ] United Kingdom Cohort National 2006 12 40-69 C 547 0 0 0 Diagnosed 1 CALIBER [39 ] United Kingdom Cohort GP records 1997 13 30+ F 16800 1 0 0 Diagnosed 1 CPS-II [50 ] United States Cohort National 1982 22 30+ C 13478 0, 23 0 0 Died 2 CoCHS [51 ] Denmark Cohort Regional 1991 22 20-93 F 900 1 0 0 Diagnosed 1 ELSA [52 ] United Kingdom Cohort National 2004 13 52+ C 352 0, 7 0 0 Diagnosed 2 EPIC-10 [53 ] Multi Cohort International 1991 19 35-70 M, F 7198 0 0 0 Diagnosed 2 [54 ] Multi Nested CC International 1991 19 35-70 C 7198 0 0 0 Diagnosed 1 EPIC-UK [55 ] United Kingdom Cohort Regional 1993 14 45-79 C 2332 0, 2, 6 0 0 Diagnosed 3 ESTON-GENOME [41 ] Estonia Cohort National 2002 13 18+ M, F 696 0, 1 0 0 Died 4i FINRISK [56 ] Finland Cohort National 1982 25 25-74 F NR 3, 8 0 0 Died 2 HAPIEE [57 ] Multi Cohort International 2002 9 NAR C 225 0 0 0 Died 1 HSE-SHS [58 ] United Kingdom Cohort National 1994 17 NAR C 1412 0, 7 0 0 Died 2 JACC [59 ] Japan Cohort Regional 1988 21 40-79 M, F 1554 0, 7, 9 x 0 Died 4 MALMO [60 ] Sweden Cohort Regional 1991 22 46-67 M, F 3217 0, 6 0 0 Diagnosed 4 MESA [61 ] United States Cohort Regional 2000 11 45-84 C 449 1, 14 0 0 Diagnosed 3 [62 ] United States Cohort Regional 2000 11 45-84 C 449 0 0 0 Diagnosed 1 NAS [63 ] United States Cohort Regional 1991 20 NAR F 137 0 0 0 Diagnosed 1 NHS [64 ] United States Cohort Medical workers 1989 17 43-68 F 3874 0 0 0 Diagnosed 1 NHS-II [65 ] United States Cohort Medical workers 1991 20 25-42 F 456 1, 15 0 0 Diagnosed 2 PREVEND [66 ] Netherlands Cohort Regional 2001 9 32-80 C 212 0, 2, 10 0 0 Diagnosed 3 USA5 [67 ] United States Cohort Regional 2000 11 55+ M, F 29931 0, 5 0 0 Died 4 WHI [68 ] United States Cohort National 1993 20 50-79 F 2975 11 0 0 Died 1 WHITEHALL [69 ] United Kingdom Cohort Civil servants 1967 43 40-69 M 3250 1 0 0 Died 1
Table 3 Details of the 31 studies of stroke
Study IDa Ref. Country Design Study population Start year Yr followed Ageb Sexc Cases Adjustd Excle Latencyf Endpoint NRRg 7CNTRY-ITALY [47 ] Italy Cohort Regional 1960 50 40-59 M 225 3 0 0 Died 1 ARIC [48 ] USA Cohort National 1987 30 45-64 C 1106 0, 14 0 0 Diagnosed 2 BIOBANK [70 ] UK Cohort National 2006 12 40-69 M, F 4662 2 0 0 Diagnosed 2 CALIBER [39 ] UK Cohort GP records 1997 13 30+ F 11842 1 0 0 Diagnosed 1 CPS-II [50 ] USA Cohort National 1982 22 30+ C 5582 0, 23 0 0 Died 2 CaCHS [38 ] Canada Cohort Regional 2001 13 20+ M, F 1636 15 0 0 Diagnosed 2 [71 ] Canada Cohort Regional 2001 11 20+ M, F 1636 0 0 0 Diagnosed 2 ELSA [52 ] UK Cohort National 2004 13 52+ C 326 0, 7 0 0 Diagnosed 2 EPIC-10 [54 ] Multi Nested CC International 1991 19 35-70 C 2187 0 0 0 Diagnosed 1 EPIC-ITALY [72 ] Italy Cohort Regional 1993 15 35-74 M, F 386 0, 2, 10 0 0 Diagnosed 6 EPIC-SPAIN [73 ] Spain Cohort Regional 1992 16 29-69 F 301 0 0 0 Diagnosed 1 EPIC-UK [55 ] UK Cohort Regional 1993 14 45-79 C 385 0, 2, 6 0 0 Diagnosed 3 ESTON-GENOME [41 ] Estonia Cohort National 2002 13 18+ M, F 156 0, 1 0 0 Died 4h HAPIEE [57 ] Multi Cohort International 2002 9 NAR C 109 0 0 0 Died 1 HSE-SHS [58 ] UK Cohort National 1994 17 NAR C 690 0, 7 0 0 Died 2 JACC [59 ] Japan Cohort Regional 1988 21 40-79 M, F 3163 0, 7, 9 x 0 Died 4 JHS [74 ] USA Cohort Regional 2000 15 21-84 C 183 0, 11 0 0 Diagnosed 2 JP8 [75 ] Japan Cohort National 1983 30 40+ M 3487 0 0 0 Died 1 MALMO [76 ] Sweden Cohort Regional 1991 22 46-67 C 305 0 0 0 Diagnosed 1 MESA [62 ] United States Cohort Regional 2000 11 45-84 C 180 0 0 0 Diagnosed 1 MILLION [28 ] United Kingdom Cohort National 1996 19 46-66 F 8103 8 0 0 Diagnosed 1 NFBC [77 ] Finland Cohort Regional 1966 49 14-46 C 352 0, 10 0 0 Diagnosed 2 NHIS [78 ] United States Cohort National 1987 24 18-95 C 2046 0, 5 x 0 Died 2 [79 ] United States Cohort National 1987 14 18-95 C 2046 0, 8, 9 0 x Died 3 [80 ] United States Cohort National 1987 28 40-79 M 2046 0, 1, 9 0 x Died 3 NHS [64 ] United States Cohort Medical workers 1989 17 43-68 F 3288 0 0 0 Diagnosed 1 NIH-AARP [81 ] United States Cohort Regional 2004 7 70+ C 1369 0, 4 0 0 Died 2 NLMS [82 ] United States Cohort National 1985 26 35-80 C 3083 0, 1, 5 x 0 Died 3 OHASAMA [83 ] Japan Cohort Regional 1998 12 60+ C 293 2 x 0 Diagnosed 1 PREVEND [66 ] Netherlands Cohort Regional 2001 9 32-80 C 83 0, 2, 10 0 0 Diagnosed 3 SCCS [84 ] United States Cohort Regional 2002 11 40-79 C 389 7 0 0 Died 1 USA5 [67 ] United States Cohort Regional 2000 11 55+ M, F 9821 0, 5 0 0 Died 4 WHITEHALL [69 ] United Kingdom Cohort Civil servants 1967 43 40-69 M 1061 1 0 0 Diagnosed 1 WHS [46 ] United States Cohort National 1992 26 45+ F 887 0, 14 0 0 Diagnosed 2
Table 4 Acute myocardial infarction and current vs never cigarette smoking – results from random effects meta-analyses
Full output table Factor Level No. of RRs No. of studies RR (95%CI) Test of heterogeneity by level (NS = P ≥ 0.1) and trend if relevant, P value All 13 10 2.72 (2.40-3.08) < 0.001 5 Sex Combined 2 2 2.98 (2.20-4.04) Males 4 4 2.30 (1.57-3.37) Females 7 7 2.83 (2.40-3.34) NS 6 Region N. America 3 2 3.42 (2.93-3.99) Europe 10 8 2.54 (2.22-2.90) < 0.01 7 Study population National 5 3 2.85 (2.16-3.77) Regional 7 6 2.69 (2.18-3.33) Other 1 1 2.51 (2.33-2.71) NS 8 Year of start of baseline < 1988 2 2 1.81 (1.28-2.56) 1988+ 11 8 2.93 (2.58-3.32) < 0.05 9 Number of cases < 1000 7 6 2.52 (1.96-3.25) 1000+ 6 4 2.87 (2.46-3.35) NS 10 Lowest age considered < 30 5 3 3.02 (2.09-4.35) 30-44 6 5 2.58 (2.20-3.04) 45+ 2 2 2.88 (2.40-3.46) NS trend NS 11 Yr of follow-up 10-< 20 10 7 2.78 (2.40-3.23) 20-< 30 2 2 2.88 (2.40-3.46) 30+ 1 1 2.11 (1.81-2.46) < 0.05 trend < 0.01 12 Endpoint Died 2 1 2.99 (1.34-6.67) Diagnosed 11 9 2.71 (2.38-3.08) NS 13 Number of adjustment factors None 1 1 1.47 (1.08-2.01) Age only 3 2 2.52 (2.34-2.71) More 9 7 2.89 (2.48-3.37) < 0.001 14 Disease definition standard No 6 7 2.43 (2.06-2.87) Yes 7 5 3.14 (2.63-3.74) < 0.05
Table 5 Ischaemic heart disease and current vs never cigarette smoking – results from random effects meta-analyses
Full output table Factor Level No. of RRs No. of studies RR (95%CI) Test of heterogeneity by level (NS = P ≥ 0.1) and trend if relevant, P value All 28 23 2.01 (1.84-2.21) < 0.001 19 Sex Combined 10 10 1.94 (1.71-2.21) Males 7 7 1.86 (1.53-2.26) Females 11 11 2.23 (1.86-2.69) NS 20 Region N. America 9 8 2.23 (1.92-2.58) Europe 17 14 1.90 (1.67-2.15) Japan 2 1 2.15 (1.73-2.69) NS 21 Study population National 9 8 2.10 (1.92-2.30) Regional 12 9 1.85 (1.56-2.19) Other 7 6 2.18 (1.77-2.69) NS 22 Year of start of baseline < 1988 5 5 1.89 (1.56-2.27) 1988+ 23 18 2.04 (1.83-2.28) NS 23 Number of cases < 1000 12 11 1.97 (1.58-2.45) 1000+ 16 12 2.04 (1.83-2.27) NS 24 Exclusive cigarettes No 26 22 2.00 (1.82-2.21) Yes 2 1 2.15 (1.73-2.69) NS 25, 26 Lowest age considered < 30 5 4 2.45 (1.77-3.39) 30-44 11 9 1.81 (1.61-2.05) 45+ 9 7 2.06 (1.76-2.42) NS trend without missing NS Missing 3 3 2.09 (1.16-3.78) 27 Yr of follow-up < 10 2 2 2.52 (1.07-5.90) 10-< 20 13 10 2.04 (1.77-2.35) 20-< 30 10 8 1.99 (1.78-2.23) 30+ 3 3 1.68 (1.23-2.29) NS trend NS 28 Endpoint Died 13 10 2.23 (1.94-2.57) Diagnosed 15 13 1.83 (1.62-2.05) < 0.05 29 Number of adjustment factors None 6 5 2.11 (1.78-2.50) Age only 5 4 1.64 (1.39-1.93) More 17 14 2.10 (1.88-2.35) < 0.05 30 Disease definition standard No 13 12 1.83 (1.59-2.10) Yes 15 11 2.17 (1.93-2.45) < 0.1
Table 6 Stroke and current vs never cigarette smoking – results from random effects meta-analyses
Full output table Factor Level No. of RRs No. of Studies RR (95%CI) Test of heterogeneity by level (NS = P ≥ 0.1) and trend if relevant, P value All 37 31 1.62 (1.48-1.77) < 0.001 35 Sex Combined 17 17 1.65 (1.52-1.50) Males 9 9 1.48 (1.21-1.80) Females 11 11 1.66 (1.39-1.99) NS 36 Region N. America 14 12 1.64 (1.48-1.83) Europe 19 16 1.71 (1.51-1.94) Japan 4 3 1.18 (1.04-1.34) < 0.001 37 Study population National 13 11 1.76 (1.47-2.11) Regional 19 15 1.55 (1.36-1.78) Other 5 5 1.51 (1.39-1.65) N.S. 38 Yr of start of baseline < 1988 8 8 1.43 (1.23-1.67) 1988+ 29 23 1.68 (1.52-1.85) < 0.1 39 Number of cases < 1000 18 16 1.66 (1.44-1.91) 1000+ 19 15 1.59 (1.41-1.78) NS 40 Exclusive cigarettes No 32 27 1.67 (1.52-1.84) Yes 5 4 1.31 (1.19-1.45) < 0.001 41, 42 Lowest age considered < 36 8 6 1.59 (1.19-2.14) 30-44 16 13 1.48 (1.35-1.62) 45+ 11 10 1.89 (1.68-2.12) < 0.01 trend without missing < 0.01 Missing 2 2 1.87 (1.54-2.28) 43 Yr of follow-up < 10 3 3 2.13 (1.80-2.53) 10-< 20 22 17 1.69 (1.52-1.89) 20-< 30 7 6 1.43 (1.29-1.60) 30+ 5 5 1.44 (1.10-1.89) < 0.001 trend < 0.001 44 Endpoint Died 16 13 1.60 (1.41-1.81) Diagnosed 21 18 1.63 (1.46-1.83) NS 45 Number of adjustment factors None 7 7 1.32 (1.08-1.62) Age only 4 3 1.70 (1.31-2.20) More 26 21 1.69 (1.53-1.88) < 0.1 46 Disease definition standard No 20 18 1.68 (1.51-1.88) Yes 17 13 1.55 (1.36-1.77) NS
Table 7 Comparison of meta-analysis relative risks for ischaemic heart disease in this study and in other publications
Ref. Region What is smoked Comparison groupa RR (95%CI) males RR (95%CI) females RR (95%CI) any Woodward et al [17 ], 2005 Asia-Pacific Cigarettes Non 1.56 (1.44-1.70) 1.73 (1.50-2.01) 1.60 (1.49-1.72) Woodward et al [18 ], 2005 Asia, Australia, New Zealand Cigarettes Non 1.86 (1.69-2.06) Nakamura et al [16 ], 2009 Asia Undefined Never 1.97 (1.66-2.33) Huxley et al [19 ], 2011 Any Cigarettes Non 1.72 (1.57-1.88) 1.92 (1.66-2.23) 1.79 (1.61-1.98) Mons et al [15 ], 2015 Any Undefined Never 1.80 (1.51-2.15) 2.26 (1.98-2.59) 2.03 (1.63-2.54)b Lee et al [5 ], 2017c North America, Europe, Asia Cigarettesd Never 1.99 (1.81-2.19) 2.12 (1.87-2.40) 2.05 (1.90-2.21) Colpani et al [13 ], 2018 Any Cigarettese Never 3.12 (2.15-4.52) Hackshaw et al [14 ], 2018 Any 20 cigarettes per day Never 2.04 (1.86-2.24) 2.84 (2.21-3.64) 2.34 (1.96-2.79) Lee et al [11 ], 2018c Japan Cigarettesd Never 1.98 (1.74-2.25) 2.59 (2.06-3.27) 2.21 (1.96-2.50) This meta-analysis North America, Europe, Japan Cigarettes Never 1.86 (1.53-2.26) 2.23 (1.86-2.69) 2.01 (1.84-2.21)
Table 8 Comparison of meta-analysis relative risks for stroke in this study and in other publications
Ref. Region What is smoked Comparison groupa RR (95%CI) males RR (95%CI) females RR (95%CI) any Woodward et al [17 ], 2005 Asia-Pacific Cigarettes Non 1.29 (1.20-1.38) 1.42 (1.26-1.62) 1.32 (1.24-1.40) Nakamura et al [16 ], 2009 Asia Undefined Never 1.34 (1.12-1.48) Peters et al [22 ], 2013 Any Cigarettes Non 1.67 (1.49-1.88) 1.83 (1.58-2.12) 1.73 (1.58-1.89) Chen et al [20 ], 2014 Western Cigarettes Never 2.27 (1.76-2.93) Mons et al [15 ], 2015 Any Undefined Never 1.44 (1.23-1.68) 1.78 (1.46-2.17) 1.59 (1.29-1.95)b Lee et al [5 ], 2017 North America, Europe, Asia Cigarettesc Never 1.42 (1.29-1.56) 1.54 (1.33-1.78) 1.48 (1.37-1.60) Wang et al [23 ], 2017 China Undefined Undefined 1.53 (1.06-2.20)b Colpani et al [13 ], 2018 Any Cigarettesd Never 2.09 (1.51-2.89) Hackshaw et al [14 ], 2018 Any 20 cigarettes per day Never 1.64 (1.48-1.82) 2.16 (1.69-2.75) 1.90 (1.54-2.35) Lee et al [11 ], 2018 Japan Cigarettesc Never 1.32 (1.16-1.51) 1.50 (1.16-1.94) 1.40 (1.25-1.57) Pan et al [21 ], 2019 Any Cigarettesc Nevere 1.54 (1.11-2.13) 1.88 (1.45-2.44) 1.92 (1.49-2.48) This meta-analysis North America, Europe, Japan Cigarettes Never 1.48 (1.21-1.80) 1.66 (1.39-1.99) 1.62 (1.48-1.77)