The risks of smoking are well documented. Now research from Japan shows that exposure to tobacco smoke both prenatally and postnatally may raise the risk of hearing problems in children. The population-based retrospective cohort study in Paediatric and Perinatal Epidemiology followed more than 50,000 children from Kobe, Japan, born between 2004 and 2010. It investigated the association of maternal smoking during pregnancy and exposure to tobacco smoke at age 4 months with hearing impairment at age 3 years in children.
Of the included children, 3.8 percent were exposed to smoking only during pregnancy; 3.9 percent were exposed only to second‐hand smoke at 4 months; and 0.9 percent were exposed to tobacco smoke during pregnancy and at 4 months. Hearing impairment prevalence at age 3 years was 4.6 percent.
The authors reported that compared with children not exposed to tobacco smoke prenatally and at 4 months, children exposed to:
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only maternal past smoking during pregnancy had a 26 percent increased relative risk of hearing impairment
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only second-hand smoke at 4 months had a 30 percent increased relative risk
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only smoking during pregnancy had a 68 percent increased relative risk
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smoking during pregnancy and second-hand smoke at 4 months had a 2.4-times increased relative risk
They caution pregnant mothers not to smoke during pregnancy and in front of children.