Clinical sepsis in neonates is responsible for the lower prevalence of developing allergy

BACKGROUND: The hygiene hypothesis proposes an association between the change in exposure to microbes and the increased incidence of atopic disease. The purpose of the present study was to perform a prospective epidemiological study of the effect of perinatal infection on the development of allergy. METHODS: Eight hundred and ten children were born at Umeda Gynecological Hospital in Yamaguchi prefecture in Japan between April 1997 and March 1998. A questionnaire survey on the development of allergic diseases was sent by mail in 2002. The presence or absence of neonatal infectious disease (clinical sepsis) and maternal complications during the gestational period and delivery, and the incidence of bacterial infection during the perinatal period, were investigated by examining hospital records. RESULTS: Data were obtained for 410 children (51%). One hundred and forty-eight children (36.1%) developed allergic diseases. Among children whose mothers had allergies, the percentage of children who developed allergic disease(s) was significantly lower in children who had had clinical sepsis in the neonatal period than in those without clinical sepsis (26.1% vs 49.7%, P < 0.03). CONCLUSIONS: Clinical sepsis in neonates might reduce the risk of developing allergic diseases in early childhood in children whose mothers have allergies.