Abstract
BACKGROUND: Autism spectrum condition (ASC) is a neurodevelopmental disorder characterized by persistent difficulties in social communication and repetitive behaviors. Emerging evidence suggests that early nutrition, particularly reduced breastfeeding exposure, may be associated with an increased risk of ASC. However, this evidence is limited, especially in non-Western populations. METHODS: We conducted an unmatched case-control study in Saudi Arabia to investigate the association between breastfeeding practices and ASC. Data were collected through an online questionnaire from mothers of children with and without ASC. Cases were children with a confirmed ASC diagnosis, and controls were neurotypical children without a diagnosis of ASC. Breastfeeding exposure was categorized according to the World Health Organization definitions (from highest to lowest exposure) as follows: exclusive, predominant, partial, or no breastfeeding. Logistic regression models were used to estimate odds ratios (OR) with 95% confidence intervals (CI). RESULTS: Between 1 October 2024 and 25 January 2025, a total of 283 participants (126 cases and 157 controls) were recruited. A dose-response relationship was observed, where decreased breastfeeding exposure was associated with progressively higher odds of ASC (OR for trend: 1.58; 95% CI 1.24, 2.01). In univariable analyses, using exclusive breastfeeding as the reference category, partial breastfeeding was associated with increased odds of ASC (OR: 2.49; 95% CI 1.40, 4.42). Similarly, children who were not breastfed had significantly higher chance of ASC than the reference category (OR: 3.46; 95% CI 1.47, 8.13). The strength of these associations was attenuated after multivariable adjustment but remained statistically significant (OR: 2.28; 95% CI 1.22, 4.25 for partial versus exclusive breastfeeding and OR: 2.86; 95% CI 1.12, 7.26 for no breastfeeding versus exclusive breastfeeding). CONCLUSIONS: Our findings suggest that reduced breastfeeding exposure is associated with increased odds of ASC. However, these results should be interpreted cautiously, considering the inherent limitation of case-control studies and the potential of reverse causality.