Neighborhood Disadvantage, Race and Ethnicity, and Postpartum Depression

IMPORTANCE: Postpartum depression (PPD) is a debilitating condition with higher rates among Black individuals. Increasingly, neighborhood disadvantage is being recognized as a contributor to poor health and may be associated with adverse postpartum mental health; however, associations between neighborhood disadvantage, race and ethnicity, and PPD have not been examined. OBJECTIVE: To investigate the association between neighborhood disadvantage and PPD and evaluate the extent to which these associations may differ by race and ethnicity. DESIGN, SETTING, AND PARTICIPANTS: This population-based cross-sectional study included 122 995 postpartum Kaiser Permanente Northern California members 15 years or older with a live birth between October 7, 2012, and May 31, 2017, and an address in the electronic health record. Analyses were conducted from June 1, 2022, through June 30, 2023. EXPOSURES: Neighborhood disadvantage defined using quartiles of the Neighborhood Deprivation Index (NDI), a validated census-based socioeconomic status measure; self-reported race and ethnicity ascertained from Kaiser Permanente Northern California electronic health records. MAIN OUTCOMES AND MEASURES: Multivariable Poisson regression was conducted to assess associations between neighborhood disadvantage, race and ethnicity, and a diagnosis of PPD. RESULTS: Of 122 995 included postpartum individuals, 17 554 (14.3%) were younger than 25 years, 29 933 (24.3%) were Asian, 8125 (6.6%) were Black, 31 968 (26.0%) were Hispanic, 47 527 (38.6%) were White, 5442 (4.4%) were of other race and ethnicity, and 15 436 (12.6%) had PPD. Higher neighborhood disadvantage and race and ethnicity were associated with PPD after covariate adjustment. Compared with White individuals, Black individuals were more likely to have PPD (adjusted relative risk [ARR], 1.30; 95% CI, 1.24-1.37), whereas Asian (ARR, 0.48; 95% CI, 0.46-0.50), and Hispanic (ARR, 0.92; 95% CI, 0.89-0.96) individuals and those identified as having other race and ethnicity (ARR, 95% CI, 0.90; 0.85-0.98) were less likely to have PPD. Associations between NDI and PPD differed by race and ethnicity (likelihood ratio test for interaction, χ(2)(12) = 41.36; P < .001). Among Black individuals, the risk of PPD was the greatest overall and increased with neighborhood disadvantage in a dose-response manner (quartile [Q] 2 ARR, 1.39 [95% CI, 1.13-1.71]; Q3 ARR, 1.50 [95% CI, 1.23-1.83]; Q4 ARR, 1.60 [95% CI, 1.32-1.93]; Cochrane-Armitage test for trend, P < .001). Neighborhood disadvantage was associated with PPD among Asian (Q2 ARR, 1.17 [95% CI, 1.04-1.31]; Q3 ARR, 1.20 [95% CI, 1.06-1.35]) and White (Q3 ARR, 1.14 [95% CI, 1.07-1.21]; Q4 ARR, 1.17 [95% CI, 1.09-1.26]) individuals and those of other race and ethnicity (Q3 ARR, 1.34 [95% CI, 1.09-1.63]; Q4 ARR, 1.28 [95% CI, 1.03-1.58]), but the magnitude of risk was lower. Neighborhood disadvantage was not associated with PPD among Hispanic individuals (eg, Q2 ARR, 1.04 [95% CI, 0.94-1.14]; Q3 ARR, 1.00 [95% CI, 0.91-1.10]; Q4 ARR, 0.98 [95% CI, 0.90-1.08]). CONCLUSIONS AND RELEVANCE: In this cross-sectional study of postpartum individuals, residing in more disadvantaged neighborhoods was associated with PPD, except among Hispanic individuals. Neighborhood disadvantage may be associated with racial and ethnic differences in postpartum mental health. Geographic targeting of mental health interventions may decrease postpartum mental health inequities.