Preterm Delivery in Relation to Neighbourhood-Level Adult Premature Mortality

To assess the influence of neighbourhood-level adult premature mortality on a woman's risk of preterm delivery (PTD).

We included 286 872 singleton live birth deliveries in Toronto, Ontario, between 2002 and 2011. The study exposure was neighbourhood premature mortality rate, expressed in quintiles (Q), among adults aged 20 to 49 years living within each of Toronto's 140 neighbourhoods. The primary study outcome was PTD at 24 to 36 weeks' gestation. Logistic regression analysis generated unadjusted ORs, adjusted ORs, and 95% CIs, controlling for maternal age, parity, marital status, material deprivation index Q, maternal and paternal birthplace, and infant sex.

For all 140 neighbourhoods, the mean rate of premature deaths was 0.66 per 100 females and 1.17 per 100 males aged 20 to 49 years. The rate of PTD increased linearly in relation to the neighbourhood rate of premature mortality among adult females, from 5.3 per 100 in Q1 with the lowest rate of premature mortality to 6.3 per 100 in Q5 (OR 1.22; 95% CI 1.13 to 1.31). The adjusted ORs were attenuated but remained significant (1.13; 95% CI 1.05 to 1.22). A similar pattern was demonstrated for the relation between neighbourhood premature mortality among adult males and PTD.

Women residing in neighbourhoods with high rates of premature adult mortality are at elevated risk of PTD, even after adjusting for measured socioeconomic factors that include marital status and material deprivation.