Table 1. Characteristics of Children in Birth Cohort.
| Characteristic | No./total No. (%) | P value | |
|---|---|---|---|
| Atopic dermatitis (n = 110) | No atopic dermatitis (n = 260) | ||
| Geographic area | |||
| Central | 79/110 (71.8) | 188/260 (72.3) | .92 |
| Eastern | 31/110 (28.2) | 72/260 (27.7) | |
| Sex | |||
| Male | 57/110 (51.8) | 151/260 (58.1) | .27 |
| Female | 53 (48.2) | 109/260 (41.9) | |
| Maternal educational level, y | |||
| ≤12 | 17/110 (15.5) | 30/260 (11.5) | .004 |
| 13-16 | 64/110 (58.2) | 194/260 (74.6) | |
| >16 | 29/110 (26.4) | 36/260 (13.8) | |
| Annual household income, $a | |||
| <32 420 | 55/108 (50.9) | 118/248 (47.6) | .84 |
| 32 420-47 763 | 30/108 (27.8) | 74/248 (29.8) | |
| >47 763 | 23/108 (21.3) | 56/248 (22.6) | |
| Exposure to tobacco smoke | |||
| Prenatalb | |||
| Yes | 43/101 (42.6) | 87/225 (38.7) | .51 |
| No | 58/101 (57.4) | 138/225 (61.3) | |
| At age 4 y | |||
| Yes | 15/110 (13.6) | 61/260 (23.5) | .03 |
| No | 95/110 (86.4) | 199/260 (76.5) | |
| Parental allergies | |||
| Maternal | |||
| Yes | 58/110 (52.7) | 114/260 (43.8) | .12 |
| No | 52/110 (47.3) | 146/260 (56.2) | |
| Paternalc | |||
| Yes | 51/86 (59.3) | 74/175 (42.3) | .01 |
| No | 35/86 (40.7) | 101/175 (57.7) | |
| Age, mean (SD), y | 3.91 (0.61) | 3.96 (0.58) | .51 |
| Birth weight, mean (SD), gd | 3128 (343.7) | 3126 (399.7) | .97 |
| Maternal age, mean (SD), ye | 32.18 (4.02) | 32.68 (4.05) | .35 |
| Gestational age at birth, mean (SD), wkf | 38.65 (1.08) | 38.70 (1.17) | .77 |
| Maternal urinary metal concentrations during pregnancy, μg/g creatinine | |||
| Arsenic | |||
| Median (IQR) | 65.92 (42.49-109.68) | 50.20 (31.92-81.34) | <.001 |
| Mean (SD) | 95.20 (98.48) | 73.97 (112.40) | |
| Estimated total inorganic arsenicg | |||
| Median (IQR) | 30.91 (27.51-37.25) | 28.62 (25.97-33.14) | <.001 |
| Mean (SD) | 35.14 (14.27) | 32.07 (16.29) | |
| Cadmium | |||
| Median (IQR) | 0.81 (0.59-1.18) | 0.81 (0.54-1.21) | .64 |
| Mean (SD) | 1.04 (0.83) | 1.05 (1.10) | |
| Lead | |||
| Median (IQR) | 1.34 (1.03-1.77) | 1.38 (0.99-1.80) | .97 |
| Mean (SD) | 2.26 (7.93) | 1.75 (3.61) | |
| Cobalt | |||
| Median (IQR) | 1.31 (0.92-2.06) | 1.37 (0.82-2.14) | .72 |
| Mean (SD) | 1.49 (0.82 | 1.66 (1.22) | |
| Copper | |||
| Median (IQR) | 17.88 (14.47-20.85) | 17.28 (14.14-21.77) | .66 |
| Mean (SD) | 19.09 (9.81) | 19.70 (12.60) | |
| Nickel | |||
| Median (IQR) | 3.74 (2.46-5.75) | 4.08 (2.40-6.80) | .37 |
| Mean (SD) | 6.07 (9.95) | 6.92 (13.45) | |
| Thallium | |||
| Median (IQR) | 0.30 (0.23-0.38) | 0.29 (0.23-0.40) | .91 |
| Mean (SD) | 0.33 (0.15) | 0.33 (0.24) | |
| Zinc | |||
| Median (IQR) | 463.90 (332.25-621.19) | 439.50 (326.38-655.59) | .94 |
| Mean (SD) | 517.90 (385.20) | 532.90 (342.90) | |
a
Data missing for 14 participants.
b
Data missing for 44 participants.
c
Data missing for 109 participants.
d
Data missing for 20 participants.
e
Data missing for 106 participants.
f
Data missing for 202 participants.
g
Calculated as the sum of 21.35241 and 0.14493 multiplied by the arsenic level.