Smoking may significantly increase the risk of hearing loss, a study of more than 50,000 participants over 8 years has found. Researchers from Japan's National Center for Global Health and Medicine analysed data from annual health checkups, which included audio testing performed by a technician and a health-related lifestyle questionnaire completed by each participant. They examined the effects of smoking status (current, former, and never smokers), the number of cigarettes smoked per day, and the duration of smoking cessation on the extent of hearing loss.