Life-course neighbourhood opportunity and racial-ethnic disparities in risk of preterm birth.

BACKGROUND: Neighbourhood opportunity, measured by poverty, income and deprivation, has been associated with preterm birth, however little is known about the contribution of early-life and life-course neighbourhood opportunity to preterm birth risk and racial-ethnic disparities. We examined maternal early-life and adult neighbourhood opportunity in relation to risk of preterm birth and racial-ethnic disparities in a population-based cohort of women under age 30.

METHODS: We linked census tract poverty data to 2 generations of California births from 1982-2011 for 403 315 white, black, or Latina mothers-infant pairs. We estimated the risk of preterm birth, and risk difference (RD) comparing low opportunity (≥20% poverty) in early life or adulthood to high opportunity using targeted maximum likelihood estimation.

RESULTS: At each time point, low opportunity was related to increased preterm birth risk compared to higher opportunity neighbourhoods for white, black and Latina mothers (RDs 0.3-0.7%). Compared to high opportunity at both time points, risk differences were generally highest for sustained low opportunity (RD 1.5, 1.3, and 0.7% for white, black and Latina mothers, respectively); risk was elevated with downward mobility (RD 0.7, 1.3, and 0.4% for white, black and Latina mothers, respectively), and with upward mobility only among black mothers (RD 1.2%). The black-white preterm birth disparity was reduced by 22% under high life-course opportunity.

CONCLUSIONS: Early-life and sustained exposure to residential poverty is related to increased PTB risk, particularly among black women, and may partially explain persistent black-white disparities.