Preconception Diet Quality Is Associated with Birth Weight for Gestational Age Among Women in the Hispanic Community Health Study/Study of Latinos

Background: The nutritional status of women in the preconception period is of paramount importance due to its role in reproduction. Objective: Our aim was to assess overall diet quality during the preconception period and its association with infant birth weight adjusted for gestational age (GA). Design: This is an observational longitudinal cohort of Hispanic people living in the United States. Participants/setting: Data are from the Hispanic Community Health Study/Study of Latinos baseline (2008-2011) and second clinic examinations (2014-2017). Included are the first 497 singleton live-born infants among the 2,556 women (younger than 45 years) who attended the second visit. Field sites were located in Miami, FL; Bronx, NY; Chicago, IL; and San Diego, CA, and represent individuals with heritage from Cuba, Dominican Republic, Mexico, Puerto Rico, and Central and South America. Main exposure: Diet assessment included two 24-hour recalls from baseline. The 2010 Healthy Eating Index (HEI-2010) was used to measure diet quality, with higher scores indicating better quality. Statistical analyses performed: Complex survey linear regression estimated the association between HEI-2010 scores (continuous variable and categorized into tertiles) and birth-weight z score and birth weight for GA percentile. Results: Mean (standard deviation) age of women was 25.8 (5.2) years and 36.4% were classified as underweight or normal weight, 30.0% were overweight, and 33.6% had obesity at baseline. Mean (standard deviation) HEI-2010 score was 56.5 (13.4), and by weight classifications was 54.4 (14.1) for underweight or normal weight and 57.7 (12.8) for overweight or obesity. Median (interquartile range) birth-weight z score was 0.5 (interquartile range [IQR], –0.2 to 1.3) overall and 0.2 (IQR, –0.5 to 1.0), 0.6 (IQR, –0.2 to 1.3), and 0.5 (IQR, –0.2 to 1.4) for the first, second, and third HEI-2010 tertile, respectively. Median birth weight for GA percentile was 68.2 (IQR, 40.2 to 89.7) overall, and 56.8 (IQR, 29.6 to 85.0), 71.5 (IQR, 42.8 to 90.0), and 70.1 (IQR, 42.9 to 91.2) by HEI-2010 tertile. In adjusted models, the highest tertile of the HEI-2010 score was associated with a higher birth-weight z score and birth weight for GA percentile, and the continuous HEI-2010 score was only associated with birth weight for GA percentile. Preconception body mass index (calculated as kg/m²) did not modify these associations. Conclusions: Overall diet quality, as measured by the HEI-2010, in the preconception period is associated with infant birth weight adjusted for GA among US Hispanic and Latina women.