Search

A growing body of literature reports associations between exposure to particulate matter with aerodynamic diameters ≤2.5 μm (PM 2.5) and 2.5–10 μm (PM 10-2.5) during pregnancy and preterm birth (PTB). However, the role of ambient temperature in PM-PTB associations was rarely investigated. In Israel, we used Maccabi Healthcare Services data to establish a population-based cohort of 381,265 singleton births reaching 24–42 weeks' gestation and birth weight of 500–5000 g (2004–2015). Daily PM and ambient temperature predictions from a satellite-based spatiotemporal model, at a 1 × 1 km spatial resolution, were linked to the date of birth and maternal residence. Mixed effects Cox regression models, adjusted for covariates, with a random intercept at the mother level were used to assess associations between mean exposure during pregnancy and PTB. We found that exposure to PM 2.5 was positively associated with PTB when the average exposure during pregnancy was either low (first quintile) or high (fifth quintile), compared to exposure in the 2nd-4th quintiles, with hazard ratios (HRs) 1.18 (95% confidence interval [CI], 1.13–1.24) and 1.07 (95% CI, 1.02–1.12), respectively. The results revealed effect modification of temperature. For mothers exposed to low (below median) average temperature during pregnancy, HRs of PTB were 0.93 (95% CI, 0.87–1.00) and 1.21 (95% CI, 1.14–1.29) for the first and fifth PM 2.5 quintiles, respectively, when compared to the 2nd-4th quintiles. However, a reverse trend was indicated for high-temperature pregnancies, where the corresponding HRs were 1.48 (95% CI, 1.39–1.58) and 0.92, (95% CI, 0.96–0.98). In conclusion, consideration of climatic factors can provide new insights into the risk of PTB as a result of exposure to PM 2.5 during pregnancy. [ABSTRACT FROM AUTHOR]

A growing body of literature reports associations between exposure to particulate matter with diameter ≤2.5 μm (PM 2.5) during pregnancy and birth outcomes. However, findings are inconsistent across studies. To assess the association between PM 2.5 and birth outcomes of fetal growth in a cohort with high prevalence of siblings by multilevel models accounting for geographical- and mother-level correlations. In Israel, we used Maccabi Healthcare Services data to establish a population-based cohort of 381,265 singleton births reaching 24–42 weeks' gestation and birth weight of 500–5000 g (2004–2015). Daily PM 2.5 predictions from a satellite-based spatiotemporal model were linked to the date of birth and maternal residence. We generated mean PM 2.5 values for the entire pregnancy and for exposure periods during pregnancy. Associations between exposure and birth outcomes were modeled by using multilevel logistic regression with random effects for maternal locality of residence, administrative census area (ACA) and mother. In fully adjusted models with a mother-level random intercept only, a 10-μg/m3 increase in PM 2.5 over the entire pregnancy was positively associated with term low birth weight (TLBW) (Odds ratio, OR = 1.25, 95% confidence interval, CI: 1.09,1.43) and small for gestational age (SGA) (OR = 1.15, 95% CI: 1.06,1.26). Locality- and ACA-level effects accounted for <0.4% of the variance while mother-level effects explained ∼50% of the variability. Associations varied by exposure period, infants' sex, birth order, and maternal pre-pregnancy BMI. Consideration of mother-level variability in a region with high fertility rates provides new insights on the strength of associations between PM 2.5 and birth outcomes. • New evidence from the Middle East – a region with scarce data. • Maternal exposure to PM2.5 was associated with fetal growth outcomes. • Associations were clearer when mother-level clustering in the data was accounted for. • Associations were modified by infant's sex, birth order and maternal pre-pregnancy BMI. • Associations were highest for low socio-economic status and for third trimester of pregnancy. [ABSTRACT FROM AUTHOR]