Exposure to cigarette smoke and inhaled pollutants in both periods (pregnancy, and from birth to JIA diagnosis) as risk factors for JIA for all patients and JIA categories.
| Variables | Total Group, n = 66 | RF–negative Polyarthritis, n = 23 | Oligoarticular JIA, n = 20 | Systemic JIA, n = 17 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OR | 95% CI | p | OR | 95% CI | p | OR | 95% CI | p | OR | 95% CI | p | |
| Low/middle socioeconomic status | 1.0 | 0.37–2.41 | 0.9 | 0.88 | 0.30–2.59 | 0.82 | 1.48 | 0.41–5.39 | 0.56 | 0.22 | 0.04–1.14 | 0.07 |
| Maternal employment | 0.045 | 0.015–0.13 | < 0.001 | 0.05 | 0.012–0.20 | < 0.001 | 0.016 | 0.01–0.19 | 0.001 | 0.03 | 0.004–0.17 | < 0.001 |
| Maternal occupational exposure | 27.4 | 6.85–109.7 | < 0.001 | 25.1 | 4.68–134.27 | < 0.001 | 168.5 | 9.6–2951.7 | 0.001 | 8.85 | 0.57–137.6 | 0.12 |
| Maternal weight gain, ideal | 0.21 | 0.08–0.55 | 0.001 | 0.10 | 0.02–0.63 | 0.01 | 0.17 | 0.05–0.59 | 0.01 | 0.13 | 0.02–0.72 | 0.02 |
| Daycare/school attendance | 0.12 | 0.04–0.44 | 0.001 | 0.15 | 0.03–0.74 | 0.02 | 0.025 | 0.003–0.18 | < 0.001 | 0.24 | 0.03–1.78 | 0.16 |
| Exposure to cigarette smoke (intrauterine and after birth) | 3.55 | 1.38–9.16 | 0.01 | 3.71 | 1.10– 12.55 | 0.04 | 8.66 | 1.51– 49.54 | 0.015 | 4.13 | 0.90–18.99 | 0.07 |
| O3 in the 2nd yr of life | ||||||||||||
| 1st tertile ≤ 80.7 µg/m3 | — | — | — | — | — | — | — | — | — | — | — | — |
| 2nd tertile = 80.8–87.1 µg/m3 | 6.50 | 2.15–20.53 | 0.001 | 4.46 | 1.10–18.88 | 0.042 | 7.45 | 1.02–54.51 | 0.04 | 10.60 | 1.69–66.45 | 0.012 |
| 3rd tertile ≥ 87.2 µg/m3 | 1.00 | 0.54–2.90 | 0.99 | 1.22 | 0.33–4.52 | 0.77 | 0.32 | 0.04–2.34 | 0.26 | 0.77 | 0.12–4.81 | 0.78 |
JIA: juvenile idiopathic arthritis; O3: ozone.