TOKYO: 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.
Even after adjusting for factors including occupational noise exposure, researchers noted a 1.2 to 1.6 increased risk of hearing loss among current smokers compared with never smokers.
While the association between smoking and high-frequency hearing loss was stronger than that of low-frequency hearing loss, the risk of both high- and low-frequency hearing loss increased with cigarette consumption.
The increased risk of hearing loss decreased within five years after quitting smoking.
"With a large sample size, long follow-up period, and objective assessment of hearing loss, our study provides strong evidence that smoking is an independent risk factor of hearing loss," said Huanhuan Hu of Japan's National Center for Global Health and Medicine.
"These results provide strong evidence to support that smoking is a causal factor for hearing loss and emphasize the need for tobacco control to prevent or delay the development of hearing loss," said Hu lead author of the study published in the journal Nicotine and Tobacco Research.