Weighing the contributions of material and social area deprivation to preterm birth.

Evidence suggests that individual socioeconomic status is a better predictor of preterm birth (PTB) than other individual social characteristics, but it is not clear if socioeconomic (material) area context is likewise more strongly related to PTB than social area characteristics. We compared material and social area deprivation to determine which was more strongly associated with PTB. Live singleton births from Québec, Canada were obtained for 1999-2006 (N = 581,898). PTB was defined as <37 completed gestational weeks. Two composite indices representing area-level material and social deprivation were used in Cox proportional hazards regression models to compute hazard ratios (HR) and 95% confidence intervals (CI) for PTB, accounting for individual-level characteristics including maternal education. Results indicated that PTB rates were higher for areas with high material (7.1%) and social (6.8%) deprivation than those with low material (5.5%) and social (5.9%) deprivation. Adjusted hazards of PTB were slightly greater for material deprivation than social deprivation. These findings indicate that material area deprivation is marginally more strongly associated with PTB than social deprivation, but it is not clear that interventions to prevent PTB should focus on material deprivation any more than on social area deprivation.