LAUSR

Sudden Unexpected Infant Death (SUID) disproportionately affects non-Hispanic Black (NHB) and American Indian/Alaskan Native (AI/AN) infants, who have lower rates of breastfeeding than other groups. No existing literature investigates if breastfeeding explains disparities in SUID rates. Using 13,077,880 live birth certificates and 11,942 linked SUID death certificates from 2015-2018, we calculated odds ratios and adjusted risk differences (AdjRD) of SUID by not-breastfeeding across 5 racial/ethnic strata in the United States. We analyzed mediation by not-breastfeeding in the race/ethnicity-SUID association. The overall SUID rate was 0.91/1,000 live births. NHB and AI/AN infants had the highest disparity in SUID relative to non-Hispanic White (NHW) infants. Overall not-breastfeeding was associated with SUID, adjusted Odds Ratio (aOR) 1.14 (95% Confidence Interval [CI]: 1.10, 1.19), the AdjRD was 0.12/1,000 live births. The aOR of not-breastfeeding for SUID was 1.07 (95% CI: 1.00, 1.14) in NHB infants, and 1.29 (95% CI: 1.14, 1.46) in Hispanic infants. Breastfeeding minimally explained the higher SUID risk in NHB infants (2.3% mediated) and the lower risk in Hispanic infants (2.1% mediated) relative to NHW infants. Competing risks likely explain the lower aOR seen in NHB infants of not-breastfeeding on SUID, suggesting that social/structural determinants must be addressed to reduce racial disparities in SUID.