Table 2 Adjusted and unadjusted relative risks of asthma in children periconceptionally and gestationally exposed to folic acid
Exposure | case | control | Unadjusted OR | 95% CI | Adjusted OR * | 95% CI |
|---|---|---|---|---|---|---|
Folic acid exposure | ||||||
No | 112 | 263 | Ref. | \ | Ref. | \ |
Yes | 436 | 553 | 1.77 | 1.60–1.96 | 1.28 | 1.14–1.43 |
Starting time | ||||||
No exposure | 112 | 263 | Ref. | \ | Ref. | \ |
Before gestation | 278 | 372 | 1.64 | 1.47–1.82 | 1.31 | 1.01–1.70 |
1st month of gestation | 62 | 85 | 1.57 | 1.33–1.85 | 1.09 | 0.96–1.23 |
> 1st month of gestation | 26 | 32 | 2.20 | 1.74–2.79 | 1.90 | 1.56–2.30 |
Duration | ||||||
No exposure | 112 | 263 | Ref. | \ | Ref. | \ |
< 4 months | 28 | 32 | 1.81 | 1.43–2.29 | 1.21 | 1.07–1.37 |
4–6 months | 269 | 400 | 1.47 | 1.32–1.63 | 1.06 | 0.88–1.27 |
> 6 month | 62 | 60 | 2.40 | 2.03–2.85 | 1.75 | 1.35–2.27 |