Childhood asthma biomarkers including zinc: An exploratory cross-sectional study

Table 1 Matching between cases and controls

	Cases (n = 40)	Controls (n = 21)	P value
Gender distribution, n (%)
Females	13 (32.5)	10 (47.5)	0.2471
Males	27 (67.5)	11 (52.5)
Age in yr, median (IQR)	7 (4)	6 (4)	0.3612
BMI Z scores, median (IQR)	-1 (0)	-1 (0)	0.9992
Coexistence of malnutrition, n (%)
Yes	35 (87.5)	21 (100)	0.1543
No	5 (12.5)	0 (0)

¹Chi-square test;

²Mann-Whitney test;

³Fisher’s exact test.

BMI: Body mass index.

Table 2 Normality tests for numeric variables of interest

Studied numerical variables	P value	Distribution
Age of the study participants	0.000a	Non-parametric
Serum zinc	0.200	Parametric
Serum IgE	0.000a	Non-parametric
Serum iron	0.188	Parametric
Ferritin	0.000a	Non-parametric
Hb	0.200	Parametric
Albumin	0.212	Parametric
BMI Z scores	0.001a	Non-parametric

^aP value is considered significant if ≤ 0.05.

BMI: Body mass index; Hb: Hemoglobin IgE: Immunoglobulin E.

Table 3 Sociodemographic criteria of the study participants

Sociodemographic criteria
Age of the study participants, yr
Median (IQR)	7 (4)
Min-max	5-12
Age of children with BA, yr
Median (IQR)	7.4 (4)
Min-max	5-12
Sex distribution of the study, n = 61 (%)
Males	38 (62.3)
Females	23 (37.7)
Sex distribution in children with BA, n = 40 (%)
Males	27 (67.5)
Females	13 (32.5)

BA: Bronchial asthma; IQR: Interquartile range.

Table 4 Biochemical lab assessment in cases vs controls, mean ± SD

	Children with BA	Healthy controls	P value
Serum zinc     Min-max	94.4 ± 24.7 47-142	85.2 ± 19 47.3-112	0.1151
Serum iron     Min-max	68.8 ± 28.8 18.7-136.8	62.4 ± 26.4 26.5-116.9	0.3891
Serum ferritin, median (Q1-Q3)     Min-max	53.1 (68.6-32.2) 4.2-329.2	30 (46-17) 2-71	0.006a,2
Serum Hb     Min-max	12 ± 0.8 9.9-13.7	12 ± 0.8 10.3-13.6	0.8571
Serum albumin     Min-max	3.9 ± 0.2 3.5-4.6	3.9 ± 0.19 3.5-4.2	0.3911
Serum IgE, median (Q1-Q3)     Min-max	264 (229-37) 0.1-2302	33 (60.5-12.7) 6.7-91	0.001a,2

^aP value is considered significant if ≤ 0.05.

¹Independent t-test;

²Mann-Whitney test.

BA: Bronchial asthma; Hb: Hemoglobin; IgE: Immunoglobulin E.

Table 5 Correlation between serum iron and hemoglobin levels and ferritin in asthmatic children

Studied covariates	Serum ferritin
	rs	P value
Serum iron	-0.077	0.637
Hb	0.204	0.208

Hb: Hemoglobin.

Table 6 Serum immunoglobulin E with degree of severity of asthma in cases of bronchial asthma, mean rank

Study participants	Mild asthma, n = 24	Moderate asthma, n = 14	Severe asthma, n = 2	P value
IgE	21.5	19.7	13.5	0.6231
Ferritin	22	16	31.5	0.1261

¹Kruskal Wallis test.

IgE: Immunoglobulin E.