Exposure to cigarette smoke and inhaled pollutants during gestation as risk factors for JIA in univariate, multilevel, and final multiple logistic regression models.
| Variables during Pregnancy | Univariate Logistic Regression Model | Multilevel Logistic Regression Model | Final Multiple Logistic Regression Model | ||||||
|---|---|---|---|---|---|---|---|---|---|
| OR | 95% CI | p | OR | 95% CI | p | OR | 95% CI | p | |
| Low/middle socioeconomic status | 2.78 | 1.5–5.2 | 0.002 | 1.59 | 0.7–3.9 | 0.31 | |||
| Employment | |||||||||
| Maternal employment | 0.16 | 0.1–0.3 | < 0.001 | 0.08 | 0.04–0.17 | < 0.001 | 0.06 | 0.02–0.2 | < 0.001 |
| Maternal occupational exposure | 3.35 | 1.4–8.0 | 0.006 | 12.1 | 4.4–33.5 | < 0.001 | 13.69 | 4.4–42.3 | < 0.001 |
| Exposure to cigarette smoke | |||||||||
| Maternal smoking | 7.20 | 1.9–27.2 | 0.004 | 3.5 | 0.8–14.4 | 0.08 | |||
| Maternal secondhand smoke exposure | 2.92 | 1.5–5.6 | 0.001 | 0.3 | 0.03–2.7 | 0.30 | |||
| Intrauterine cigarette smoke exposure | 3.55 | 1.9–6.8 | < 0.001 | 11.5 | 1.3–16.7 | 0.03 | 3.43 | 1.5–8.1 | 0.005 |
| > 20 cigarettes/day | 1.67 | 0.6–4.9 | 0.35 | ||||||
| Gestational and perinatal-related factors | |||||||||
| Maternal weight gain | |||||||||
| Under ideal, < 11.5 kg | 2.02 | 1.1–3.7 | 0.030 | 1.0 | 0.4–2.3 | 0.90 | |||
| Ideal, 11.5–16 kg | 0.34 | 0.2–0.7 | 0.002 | 0.3 | 0.1–0.9 | 0.02 | 0.36 | 0.2–0.8 | 0.017 |
| Above ideal, > 16 kg | 1.50 | 0.7–3.4 | 0.320 | ||||||
| Alcohol consumption | 3.84 | 0.3–43.2 | 0.280 | ||||||
| Prematurity | 2.38 | 0.7–8.1 | 0.170 | 2.0 | 0.6–6.9 | 0.30 | |||
| Birth weight | |||||||||
| < 2.5 kg | 1.22 | 0.5–3.3 | 0.700 | ||||||
| 2.5–4.0 kg | 0.81 | 0.3–2.0 | 0.640 | ||||||
| > 4.0 kg | 1.91 | 0.3–13.9 | 0.520 | ||||||
| Home/work distance to gas stations, factories, and quarries | |||||||||
| < 100 m | 0.83 | 0.4–1.9 | 0.650 | ||||||
| 100–200 m | 0.60 | 0.2–1.7 | 0.350 | ||||||
| 200–500 m | 0.26 | 0.1–0.6 | 0.001 | 1.47 | 0.6–3.5 | 0.390 | |||
| Traffic exposure | |||||||||
| Commute time from home to work | 1.55 | 0.65–3.68 | 0.32 | ||||||
| < 30 min | 0.52 | 0.14–1.91 | 0.33 | ||||||
| 30–60 min | 0.86 | 0.35–2.13 | 0.75 | ||||||
| Air pollutants | |||||||||
| SO2 in 2nd trimester of pregnancy | |||||||||
| 1st tertile ≤ 9.9 µg/m3 | — | — | — | — | — | ||||
| 2nd tertile = 10.0–15.5 µg/m3 | 1.41 | 0.7–2.9 | 0.36 | 0.68 | 0.26–1.73 | 0.40 | |||
| 3rd tertile ≥ 15.6 µg/m3 | 0.35 | 0.2–0.8 | 0.01 | 0.42 | 0.16–1.24 | 0.09 | |||
| Season | |||||||||
| Early pregnancy | |||||||||
| Summer | — | 0.55–3.27 | — | ||||||
| Autumn | 1.34 | 0.46–2.92 | 0.51 | ||||||
| Winter | 1.16 | 0.80–4.87 | 0.76 | ||||||
| Spring | 1.98 | 0.55–3.27 | 0.21 | ||||||
| Late pregnancy | |||||||||
| Summer | — | — | — | ||||||
| Autumn | 0.78 | 0.34–1.81 | 0.51 | ||||||
| Winter | 1.57 | 0.71–3.45 | 0.76 | ||||||
| Spring | 0.64 | 0.26–1.58 | 0.21 | ||||||
JIA: juvenile idiopathic arthritis; SO2: sulfur dioxide.