LAUSR

Weight gain in the first six months of life is a predictor of future obesity with rapid infant weight gain (RIWG) (change > 0.67 SD in weight for age Z score from birth to 6 months of age), a strong predictor for obesity at age 5. We recruited a multi-racial birth cohort of primarily Latinx mothers and newborns at two San Francisco hospitals. Dried blood spots were taken from infants for leukocyte telomere length (LTL) analysis. Multivariable models were used to evaluate risk factors for RIWG, weight for age Z score (WAZ) change and WAZ at 6 months including gestational and/or pre-existing hypertension and LTL. Separate models were run for term infants ( > = 37 weeks). Slightly over one third of infants (35.76%) had RIWG (total N = 330). Hypertension in pregnancy and/or pre-existing hypertension (OR 2.16, 95%CI 1.05–4.45) and birthweight Z score (OR 0.42, 95%CI 0.28–0.63) were associated with RIWG. Similarly, maternal hypertension was positively and birthweight Z score was negatively associated with WAZ score change (Coeff = 0.37, 95%CI 0.08–0.70; Coeff=-0.47, 95%CI -0.61-(-)0.34 respectively). LTL at birth was also positively associated with WAZ score change (Coeff = 0.41, 0.04–0.78). Birthweight Z score was associated with WAZ score at 6 months (OR 0.55795%CI 0.43–0.71) as was maternal hypertension (Coeff = 0.36 (95% CI, 0.06–0.66)). In our primarily Latinx cohort, there were similar risk factors for RIWG and WAZ change from birth to 6 months of age. Pre-existing and/or gestational hypertension was associated with RIWG and WAZ change. Longer LTL at birth may be a marker of greater WAZ change.