Breastfeeding and risk of febrile seizures in the first 3 years of life: 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 3 years of life.

Methods: We analyzed the dataset of the Japan Environment and Children's Study (JECS), which is a birth cohort study undertaken to elucidate the influence of environmental factors on children's health during the fetal period and early childhood. Information on feeding duration and feeding pattern, as well as information on febrile seizures, were obtained from questionnaires sent to mothers/caregivers. We categorized a child as having experienced FS if the child was reported as having been diagnosed with FS in the first 3 years. Modified Poisson regression with a robust error variance was used to estimate the effect of duration of breastfeeding and the risk of FS.

Results: Of the 84,321 children included in the analysis, 6264 (7.4%) were reported to have experienced FS at least once in the first 3 years of life. Multivariate analyses showed that the risk of FS during the first 3 years of life tended to decrease as the duration of breastfeeding increased. Male sex and frequent fever episodes were also associated with an increased risk of FS.

Conclusions: Continued breastfeeding until 2 years of age, the most susceptible age for FS, had a small but protective effect on FS.