Infant feeding practices and autism spectrum disorder in US children aged 2-5 years: the national survey of children's health (NSCH) 2016-2020.

Objective: To investigate the relationship between infant feeding practices and autism spectrum disorder (ASD) among children aged 2-5 years in the United States (US).

Methods: Data from the 2016-2020 National Survey of Children's Health, a nationally representative cross-sectional survey, were utilized for this study. Questionnaires were administered to parents of children aged 2-5 years to gather information on ASD diagnosis, infant feeding practices, and demographic factors (e.g., child sex, ethnic group, and maternal age at birth). Logistic regression with sample weights was employed to assess the association between infant feeding practices and ASD, while controlling for demographic variables. Polynomial regression models were used to examine trends in exclusive breastfeeding and ever breastfeeding rates among children with and without ASD.

Results: A total of 35,050 children aged 2-5 years were analyzed, including 616 diagnosed with ASD, after excluding participants with missing information on breastfeeding and ASD diagnosis. Of these children with ASD, 76.6% (n = 472) had a breastfeeding history, with 67.5% (n = 416) engaged in partial breastfeeding and 9.1% (n = 56) exclusively breastfed. Adjusted odds ratios for each additional month of breastfeeding compared to never being breastfed were 0.98 (95% CI, 0.96-1.01). The adjusted odds ratios for breastfeeding durations of > 0-6 months, > 6-12 months, > 12-24 months, and > 24 months were 0.81 (95% CI, 0.50-1.31), 0.65 (95% CI, 0.36-1.18), 0.81 (95% CI, 0.44-1.49), and 0.48 (95% CI, 0.23-1.01), respectively. Compared to children who were never breastfed, the adjusted odds ratio for children who were ever breastfed was 0.74 (95% CI, 0.47-1.18). Among children with ASD, the proportion of ever breastfeeding declined from 82.0% in 2017 to 64.3% in 2020, while exclusive breastfeeding decreased from 12.0% in 2016 to 4.2% in 2020.

Conclusions and relevance: Although no significant association was found between infant feeding practices and ASD among US children aged 2-5 years, the rates of breastfeeding, particularly exclusive breastfeeding, were suboptimal among children with ASD. This highlights the need for specific policies and practices to promote and support breastfeeding among parents of children with ASD or those at high risk of having a child with ASD.