Breastfeeding and risk of febrile seizures in infants: The Japan Environment and Children's Study.

OBJECTIVE: Our study was conducted to examine the association between breastfeeding and febrile seizures (FS) in the first year of life.

METHODS: We used data from a birth cohort study, the Japan Environment and Children's Study (JECS). In a self-administered questionnaire, we asked participants the duration of breastfeeding and whether their children were diagnosed as having FS during their first 12 months. We estimated the association of duration and exclusiveness of breastfeeding with the FS by using multiple logistic regression analysis.

RESULTS: Of 84,082 children, 995 (1.2%) were diagnosed as having FS by the age of 12 months. The prevalence of FS was higher in children who were breastfed for shorter duration. Multiple logistic regression analysis showed that, compared with children breastfed for less than 1 month, those breastfed for 4-6 months and 7-12 months had lower risks of FS (adjusted odds ratio [aOR], 0.65 [95% confidence interval {CI}, 0.42-0.99]; aOR, 0.66 [95% CI: 0.45-0.96], respectively). Moreover, compared with infants who received both breast milk and formula milk for 6 months, infants who were breastfed exclusively for 6 months had lower risk of FS (aOR: 0.78 [95% CI: 0.64-0.95]).

CONCLUSIONS: Our results suggest that breastfeeding has a protective effect against FS in the first year of life.