Abstract Body: Background: Breastfeeding is linked with single indicators of maternal and child cardiovascular health (CVH), but its association with comprehensive childhood CVH as defined by AHA Life’s Essential 8 (LE8) criteria is unclear. We investigated whether breastfeeding duration and exclusivity were associated with early childhood CVH.

Methods: We analyzed data from mother-child dyads in the Environmental influences on Child Health Outcomes (ECHO) Cohort and with data on breastfeeding and child CVH outcomes at age 3-8 years. Breastfeeding duration was categorized as never/<1 month [reference], 1 to <6 months, 6 to <12 months, and ≥12 months, and secondarily, exclusive breastfeeding duration as never [reference], <3 months, 3 to <6 months, and ≥6 months. The outcome was a modified LE8 using available BMI, blood pressure, diet, sleep, and secondhand smoke data and analyzed as a continuous composite score and dichotomized as high CVH (LE8 ≥80) vs moderate/ low CVH (LE8<80). Modified Poisson regression models were used, with multiple imputation for missing covariates and adjustment for maternal age at birth, parity, education, employment, pre-pregnancy BMI, hypertensive disorders of pregnancy or gestational diabetes, cesarean delivery, and gestational age at birth.

Results: The cohort included 5,278 maternal-child dyads (median child age 5.7 years [IQR:4.7-6.9]); 38.5% never/ breastfed for <1 month, 16.4% 1 to <6 months, 25.1% 6 to <12 months and 20.0% for ≥12 months; and 29.9% exclusively breastfed for <3 months, 16.8% 3 to <6 months, and 11.7% ≥6 months. Mean LE8 score was 82.5 (SD:14.5), and 62.4% had high CVH. Compared to never/<1 month of breastfeeding, children breastfed for 6 to <12 months (mean diff: 2.16; 95% CI:1.00–3.32) and ≥12 months (mean diff: 3.66; 95% CI:2.26–5.07) had higher LE8 scores and greater likelihood of high CVH (aRR:1.21; 95% CI:1.06–1.39 and aRR:1.31; 95% CI:1.13–1.52, respectively) (TABLE 1). Exclusive breastfeeding for 3 to <6 months and ≥6 months was associated with higher LE8 scores (mean diff: 1.97; 95% CI:0.66–3.29 and mean diff: 3.36; 95% CI:1.85–4.87, respectively), and increased likelihood of high CVH (aRR:1.18; 95% CI:1.01–1.37 and aRR:1.30; 95% CI:1.11–1.52, respectively) (TABLE 2).

Conclusions: Longer duration of any or exclusive breastfeeding was associated with higher LE8 scores in early childhood. These results from across the US underscore breastfeeding as a modifiable early-life exposure with potential CVH benefits.