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Table 2 Study sample characteristics

From: Association between levels of persistent organic pollutants in adipose tissue and cryptorchidism in early childhood: a case–control study

  Cases N (%) or mean ± SD, IQR Controls N (%) or mean ± SD, IQR Missing case, control pa
Total N 44 38   
Gestational diabetes 8 (21 %) 4 (13 %) 5, 7 0.58
Parity    3, 1 0.24
 0 23 (56 %) 15 (41 %)   
 1 7 (17 %) 13 (35 %)   
 2 9 (22 %) 6 (16 %)   
 3 2 (5 %) 3 (8 %)   
Maternal smoking during pregnancy 5 (18 %) 2 (9 %) 16, 16 0.47
Maternal age (years)* 32.3 ± 4.9, 29.6 ± 6.3, 1, 0 0.04*
28.7–35.1 24.5–35.1
Months breastfed in previous pregnancies 3.4 ± 5.8, 6.2 ± 8.8, 14, 8 0.51
0–4.0 0–10.8
Mother’s weight before pregnancy (kg) 68.6 ± 16.7, 68.6 ± 19.7, 5, 8 0.92
56.0–75.7 57.2–71.0
Length of gestation (weeks)* 39.4 ± 2.9, 38.2 ± 3.0, 6, 7 0.04*
38.8–41.0 37.6–40.6
Birth weight (g) 3460 ± 680, 3170 ± 770, 5, 7 0.07
3200–3875 2955–3630
Duration of exclusive breastfeeding (months) 2.7 ± 2.1, 2.8 ± 2.1, 5, 4 0.87
0.85–4.0 1.0–4.0
Total duration of breastfeeding (months) 5.8 ± 4.5, 7.1 ± 5.7, 4, 5 0.26
2.0–8.0 3.0–12.0
Age at operation (years) 2.3 ± 1.0, 2.9 ± 2.2, 0, 0 0.53
1.9–2.5 1.2–4.0
  1. IQR Interquartile range. aFor the difference between cases and controls. *Statistically significant (p < 0.05)