Mediterranean-style diet and adverse pregnancy outcomes by race and nativity in a large multiracial US Birth Cohort

Background: Adverse pregnancy outcomes (APOs) cause neonatal morbidity and mortality and heighten the risk of long-term cardiovascular diseases. This study investigated APO disparities within a cohort of racially and ethnically diverse, low-income urban women, focusing on the intersectionality of race, ethnicity, and nativity status in relation to Mediterranean-style diet (MSD) adherence. Methods: Data were derived from the Boston Birth Cohort which is a large cohort of racially and ethnically diverse urban low-income women who were recruited from October 1998 to February 15, 2016, at Boston Medical Center. MSD scores (MSDS) were based on food questionnaires administered 24 to 72 hours postpartum. We performed logistic regression to examine the association of the MSDS with composite and individual APOs in the cohort and across racial/ethnic and nativity groups. Results: Among 8470 women (mean [standard deviation {SD}] age: 28.2 [6.5] years), 47% were Black and 29% were Hispanic. Compared with those in the lowest MSDS tertile, women in the highest tertile had 28% lower odds of any APO (adjusted odds ratio [aOR]: 0.72; 95% confidence interval [CI]: 0.64-0.81); 22% lower odds of any preeclampsia, eclampsia, or hemolysis, elevated liver enzymes, and low platelet syndrome (aOR: 0.78; 95% CI: 0.64-0.95); 28% lower odds of gestational diabetes (aOR: 0.72, 95% CI: 0.59-0.87); 17% lower odds of preterm birth (aOR: 0.83; 95% CI: 0.73-0.94); and 24% lower odds of low birth weight (aOR: 0.76; 95% CI: 0.67-0.87). APO prevalence was higher in the lowest tertile (US-born: 55%; foreign-born: 45%) than in the highest tertile (US-born: 48%; foreign-born: 38%). In the subgroup analysis, higher MSD adherence during pregnancy was associated with lower APO odds among both US-born and foreign-born Black women. Conclusions: Increased MSD adherence is associated with lower odds of developing any APO and individual APOs. Despite nativity-related disparities in individual race and ethnicity groups, the MSD should be considered when assessing and mitigating APO risk.