Exposure to smoking before and after birth linked to hearing impairment in toddlers

The prevalence of hearing impairment at age three years was 4.6 per cent. Compared with children not exposed to tobacco smoke prenatally and at four months, children exposed to only maternal past smoking during pregnancy had a 26 per cent increased relative risk of hearing impairment, children exposed to only second-hand smoke at four months had a 30 per cent increased relative risk, those exposed to only smoking during pregnancy had a 68 per cent increased relative risk, and those exposed to smoking during pregnancy and second-hand smoke at four months had a 2.4-times increased relative risk.

“Although public health guidelines already discourage smoking during pregnancy and in front of children, some women still smoke during pregnancy and many young children are exposed to second-hand smoke,” said senior author Koji Kawakami, Kyoto University, in Japan. “This study clearly shows that preventing exposure to tobacco smoke during pregnancy and postnatally may reduce the risk of hearing problems in children. The findings remind us of the need to continue strengthening interventions to prevent smoking before and during pregnancy and exposure to second-hand smoke in children.”

Reference: Calistus Wilunda, Satomi Yoshida, Shiro Tanaka, Yuji Kanazawa, Takeshi Kimura, Koji Kawakami. Exposure to tobacco smoke prenatally and during infancy and risk of hearing impairment among children in Japan: A retrospective cohort study. Paediatric and Perinatal Epidemiology, 2018; DOI: 10.1111/ppe.12477