Table 2 Relationship between different variables and blood lead concentrations of study subjects

Variable Mean ± SD Median [IQR] Test result
Gender
Boy 2.40 ± 2.85 1.90 [1.10–3.20] z = 0.86
p = 0.39
Girl 2.58 ± 2.40 1.70 [1.10–2.80]
Age
≥ 72 month 3.03 ± 2.28 2.40 [1.10–4.60] χ2 = 5.58
p = 0.13
12–24 month 2.86 ± 4.15 1.85 [1.10–2.60]
24–48 month 2.08 ± 1.34 1.70 [1.10–2.50]
48–72 month 2.28 ± 2.19 1.70 [1.10–2.80]
Exposure to paint
Yes 2.92 ± 3.32 2.10 [1.20–3.30] z = 1.39
p = 0.16
No 2.39 ± 2.46 1.80 [1.10–2.75]
Exposure to soil
Yes 2.49 ± 1.61 2.20 [1.10–3.25] z = 1.02
p = 0.31
No 2.48 ± 2.75 1.80 [1.10–2.70]
Occupation of father
Employee 2.18 ± 1.33 1.90 [1.10–2.80] χ2 = 3.25
p = 0.66
Martial 2.82 ± 2.10 2.10 [1.10–4.15]
Laborer 3.20 ± 3.96 1.80 [1.20–3.30]
Repairman 2.30 ± 1.20 2.25 [1.35–2.97]
Driver 1.79 ± 0.87 1.70 [1.00–2.30]
Self-employment 2.42 ± 2.85 1.10 [1.70–1.70]
Education levels of parents
Primary school 3.04 ± 3.89 1.60 [1.10–3.20] χ2 = 0.87
p = 0.83
Middle School 2.46 ± 1.64 2.05 [1.12–3.30]
Diploma 2.51 ± 2.96 1.80 [1.10–2.75]
Bachelor 2.16 ± 1.43 1.80 [1.10–2.80]
Occupation of mother
Housewife 2.45 ± 2.64 1.80 [1.10–2.80] χ2 = 1.79
p = 0.41
Employment 2.47 ± 1.61 1.90 [1.12–3.42]
Self-employment 3.29 ± 4.26 2.05 [1.40–3.32]
Opium use in parents
Yes 2.43 ± 1.53 2.10 [1.17–3.12] z = 0.64
p = 0.52
No 2.48 ± 2.66 1.80 [1.10–2.80]
Cigarette smoking
Yes 2.49 ± 2.70 1.90 [1.20–3.17] z = 0.58
p = 0.56
No 2.32 ± 1.41 1.80 [1.10–2.80]