摘要：Objectives. We examined associations between longitudinal neighborhood poverty trajectories and preterm birth (PTB). Methods. Using data from the Neighborhood Change Database (1970–2000) and the American Community Survey (2005–2009), we categorized longitudinal trajectories of poverty for California neighborhoods (i.e., census tracts). Birth data included 23 291 singleton California births from the Maternal and Infant Health Assessment (2003–2009). We estimated associations (adjusted for individual-level covariates) between PTB and longitudinal poverty trajectories and compared these to associations using traditional, cross-sectional measures of poverty. Results. Compared to neighborhoods with long-term low poverty, those with long-term high poverty and those that experienced increasing poverty early in the study period had 41% and 37% increased odds of PTB (95% confidence interval [CI] = 1.18, 1.69 and 1.09, 1.72, respectively). High (compared with low) cross-sectional neighborhood poverty was not associated with PTB (odds ratio = 1.08; 95% CI = 0.91, 1.28). Conclusions. Neighborhood poverty histories may contribute to an understanding of perinatal health and should be considered in future research. Compared with infants born full-term, those born preterm are at increased risk for neonatal and infant mortality, as well as respiratory, intestinal, immune, neurological, cardiovascular, hearing, and vision problems that can appear in childhood and adulthood. 1–4 Despite decades of research on the determinants of preterm birth (PTB), its causes remain poorly understood and little progress in prevention has been made. Individual factors such as maternal age, current income, education, and health behaviors do not fully account for the high prevalence of PTB (12% of US live births in 2010), 5,6 raising questions about whether broader contextual factors, such as an individual’s neighborhood environment, may also influence birth outcomes. 7,8 Many studies have found relationships between neighborhood characteristics and birth outcomes, even after adjustment for individual-level factors. 7,8 Hypothesized mechanisms through which neighborhood environments may influence birth outcomes include social factors (e.g., social organization and norms, crime, racial segregation, and residential stability), availability of resources (e.g., health care, food, tobacco and alcohol, quality education, recreational activities, and police protection), and physical attributes (e.g., exposure to pollution, toxins, and noise; exposure to advertising; and housing conditions). 7 Adverse neighborhood environments (i.e., those characterized by attributes such as high crime, limited access to resources, and poor housing conditions) are generally closely aligned with socioeconomic disadvantage, which many studies use as an indicator of a potentially health-damaging neighborhood environment. A growing body of literature demonstrates that low neighborhood socioeconomic status (SES) is associated with increased odds of PTB. 9–12 These studies—as well as most studies examining associations between neighborhood characteristics and health—have typically used measures of neighborhood disadvantage from 1 point in time (usually the most recent US Census or inter-Census estimates). These cross-sectional measures, however, fail to reflect the fact that neighborhood environments are formed over decades as a result of dynamic economic, social, and political forces. 13 For example, neighborhoods that have experienced decades of socioeconomic disadvantage may differ from neighborhoods that have experienced more recent socioeconomic decline with respect to the social factors, availability of resources, and physical attributes that may influence birth outcomes. Compared with shorter-term socioeconomic disadvantage, long-term disadvantage may be correlated with a greater lack of infrastructure, more racial segregation, or higher crime, factors associated with poor birth outcomes. 14–16 Similarly, neighborhoods with a history of socioeconomic advantage will likely differ from those that have only recently experienced economic growth. Neighborhood economic improvement may lead to increased private and public investment, perceived safety, and access to resources such as health care and healthy food, 17,18 but it may also act as a stressor for families struggling to cope with rising rents and property taxes, and incoming residents may be less invested in the social structure of the neighborhood. 19 To date, little research has attempted to measure the long-term socioeconomic characteristics of neighborhoods and link them with health outcomes. We aimed to (1) describe longitudinal trajectories of neighborhood poverty using neighborhood-level data from 1970 to 2009 and (2) compare associations between longitudinal and cross-sectional measures of neighborhood poverty and PTB in a statewide survey of postpartum women.
