Table 4.
Associations between 10 ug/m3 increase in PM2.5 and infant bronchiolitis one day prior to clinical encounter (Lag 1) and four days prior to clinical encounter (Lag 4) stratified by susceptibility risk factors.
| OR (95%CI)a | Lag1 | p-interactionb | Lag 4 | p-interactionb |
|---|---|---|---|---|
| Season of Dxc | ||||
| Cold | 1.08 (1.03, 1.13) | 0.188 | 1.04 (1.00, 1.09) | 0.489 |
| Warm | 1.00 (0.80, 1.24) | – | 1.01 (0.90, 1.13) | – |
| Gestational Age | ||||
| Term >37 weeks | 1.04 (0.99, 1.09) | 0.018 | 1.04 (1.00, 1.09) | 0.978 |
| Preterm ≤ 37 weeks | 1.17 (1.08, 1.28) | – | 1.04 (0.97, 1.13) | – |
| Birthweight | ||||
| Normal Weight ≥2500 g | 1.06 (1.02, 1.11) | 0.052 | 1.03 (0.99, 1.08) | 0.595 |
| Low Birth Weight <2500 g | 1.12 (0.98, 1.27) | – | 1.09 (0.95, 1.24) | – |
| Breastfeeding Initiation in Hospital at Birth | ||||
| Yes | 1.05 (0.99, 1.10) | 0.101 | 1.03 (0.98, 1.08) | 0.531 |
| No | 1.13 (1.05, 1.22) | – | 1.06 (0.97, 1.15) | – |
| Subsequent Infant Bronchiolitis Clinical Encounter | ||||
| No | 1.07 (1.02, 1.12) | 0.459 | 1.04 (0.99, 1.07) | 0.375 |
| Yes | 1.15 (1.01, 1.31) | – | 0.98 (0.85, 1.13) | – |
| Infant Sex | ||||
| Male | 1.08 (1.02, 1.14) | 0.716 | 1.05 (1.00, 1.11) | 0.501 |
| Female | 1.06 (0.99, 1.13) | – | 1.02 (0.95, 1.09) | – |
| Age of Infant at Time of Clinical Encounter | ||||
| 3 weeks–6months | 1.06 (0.99, 1.12) | 0.650 | 1.09 (1.02, 1.15) | 0.027 |
| 6 months–1year | 1.08 (1.02, 1.15) | – | 0.99 (0.93, 1.05) | – |
| Delivery Payment Source | ||||
| Health Maintenance Organization | 1.04 (0.98, 1.10) | – | 1.04 (0.98, 1.10) | – |
| Medicaid/CommonHealth | 1.09 (1.02, 1.17) | 0.331 | 1.04 (0.97, 1.11) | 0.979 |
| Other | 1.11 (1.00, 1.23) | 0.330 | 1.04 (0.96, 1.15) | 0.842 |
| Median Income of Census Block Group | ||||
| <$20 000 | 0.97 (0.83, 1.14) | 0.242 | 0.97 (0.83, 1.14) | 0.586 |
| $20 000–$70 000 | 1.09 (1.03, 1.15) | 0.534 | 1.04 (0.99, 1.10) | 0.987 |
| >$70 000 | 1.06 (0.99, 1.14) | – | 1.04 (0.97, 1.12) | – |
| Maternal Race | ||||
| Non-Hispanic White | 1.06 (1.00, 1.12) | – | 1.06 (1.01, 1.12) | – |
| Non-Hispanic Black | 1.11 (0.97, 1.27) | 0.441 | 1.13 (0.99, 1.30) | 0.368 |
| Hispanic | 1.06 (0.97, 1.15) | 0.845 | 0.96 (0.88, 1.05) | 0.054 |
| Asian | 1.27 (1.02, 1.57) | 0.128 | 0.98 (0.79, 1.21) | 0.432 |
| Other | 1.07 (0.83, 1.36) | 0.805 | 0.99 (1.75, 1.30) | 0.608 |
a
Model adjusted for lagged temperature, barometric pressure, humidity, and holiday indicator.
b
p-interaction generated from interaction term of susceptibility risk factor and PM2.5 in full model.
c
Warm months are May through October and cold months are January through April and November through December.