Table 2. Risk factors for respiratory tract infections in infancy.
| LRTIs | URTIs | |||||
|---|---|---|---|---|---|---|
| aOR* | 95% CI | P value | aOR* | 95% CI | P value | |
| Sex (male) | 1.53 | (1.01, 2.31) | 0.046 | 1.04 | (0.75, 1.45) | 0.799 |
| Parental history of allergic disease | 0.87 | (0.58, 1.30) | 0.500 | 0.97 | (0.70, 1.35) | 0.863 |
| Gestational age | 0.94 | (0.80, 1.10) | 0.450 | 0.94 | (0.83, 1.08) | 0.393 |
| Cesarean section delivery | 1.14 | (0.74, 1.75) | 0.550 | 0.75 | (0.53, 1.06) | 0.098 |
| Higher maternal education state | 1.08 | (0.74, 1.58) | 0.683 | 1.12 | (0.82, 1.54) | 0.468 |
| Maternal age at birth | 0.99 | (0.93, 1.05) | 0.713 | 1.06 | (1.01, 1.11) | 0.019 |
| Maternal body mass index | 1.04 | (0.96, 1.12) | 0.363 | 0.94 | (0.88, 1.01) | 0.078 |
| Higher PM2.5 during pregnancy | 2.11 | (1.12, 3.99) | 0.021 | 1.23 | (0.71, 2.15) | 0.463 |
| Higher PM2.5 at 6 months of age | 0.89 | (0.37, 2.18) | 0.801 | 1.00 | (0.52, 1.94) | 0.999 |
| Maternal ETS exposure during pregnancy | 1.33 | (0.87, 2.04) | 0.193 | 1.15 | (0.82, 1.62) | 0.414 |
| Infantile ETS exposure at 1 year | 0.87 | (0.53, 1.42) | 0.576 | 0.79 | (0.53, 1.17) | 0.241 |
| Nrf2 GG genotype | 1.27 | (0.82, 1.97) | 0.290 | 0.55 | (0.39, 0.78) | 0.001 |
| GSTP1 AG or GG genotype | 1.53 | (0.98, 2.38) | 0.062 | 0.89 | (0.62, 1.28) | 0.523 |
| GSTM1 null genotype | 1.69 | (1.07, 2.67) | 0.024 | 0.91 | (0.64, 1.30) | 0.612 |
*Odds ratios were adjusted for maternal age, maternal body mass index, maternal educational state, infant sex, gestational age, delivery mode, and family history of allergy.
ETS, environmental tobacco smoke; GSTM1, glutathione S-transferase-mu 1; GSTP1, glutathione S-transferase-pi 1; Nrf2, nuclear factor erythroid 2-related factor; PM2.5, fine particulate matter; LRTIs, lower respiratory tract infections; URTIs, upper respiratory tract infections.