Exposure to cigarette smoke and inhaled pollutants after birth as risk factors for JIA in univariate, multilevel, and final multiple logistic regression models.
| Variables after Birth | 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 | 2.6 | 1.0–4.4 | 0.052 | |||
| Secondhand smoke exposure at home | 3.28 | 1.7–6.2 | < 0.001 | 3.6 | 1.8–7.3 | < 0.001 | |||
| Daycare/school attendance | 0.17 | 0.1–0.4 | < 0.001 | 0.10 | 0.01–0.3 | < 0.001 | |||
| Home/school distance to gas stations, factories, and quarries | |||||||||
| < 100 m | 1.54 | 0.8–2.9 | 0.19 | 1.7 | 0.7–3.5 | 0.188 | |||
| 100–200 m | 1.43 | 0.7–2.7 | 0.26 | ||||||
| 200–500 m | 1.27 | 0.7–2.3 | 0.43 | ||||||
| Traffic exposure | |||||||||
| Commute time from home to daycare/school | |||||||||
| < 30 min | 2.03 | 0.9–4.6 | 0.09 | 1.5 | 0.5–4.2 | 0.47 | |||
| 30–60 min | 0.38 | 0.1–1.2 | 0.09 | 0.5 | 0.1–2.2 | 0.36 | |||
| > 60 min | 1.08 | 0.4–3.0 | 0.89 | ||||||
| Air pollutants | |||||||||
| O3 in the 2nd yr of life | |||||||||
| 1st tertile ≤ 80.7 µg/m3 | — | — | — | — | — | — | — | — | — |
| 2nd tertile = 80.8–87.1 µg/m3 | 2.22 | 1.1–4.7 | 0.03 | 2.0 | 1.05–4.2 | 0.04 | 2.76 | 1.20–6.37 | 0.017 |
| 3rd tertile ≥ 87.2 µg/m3 | 1.01 | 0.4–2.1 | 0.91 | 0.9 | 0.2–4.0 | 0.84 | 1.26 | 0.52–3.00 | 0.610 |
JIA: juvenile idiopathic arthritis; O3: ozone.