A new study has found that smoking may significantly increase the risk of both high-frequency and low-frequency hearing loss and the risk of hearing loss could significantly decrease if one quit smoking.

A new study suggests that smoking affects the ability to hear both high and low frequency sounds. "These results provide strong evidence to support that smoking is a causal factor for hearing loss and emphasise the need for tobacco control to prevent or delay the development of hearing loss," said lead author Huanhuan Hu from the National Centre for Global Health and Medicine in Japan.

For the study, published in the journal Nicotine and Tobacco Research, researchers included 50,195 people, aged between 20 to 64 years and free of hearing loss. The researchers 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. The participants were followed up for a maximum of eight years. 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.

During follow-up, 3,532 individuals developed high-frequency hearing loss, and 1,575 developed low-frequency hearing loss. 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 researcher said. The increased risk of hearing loss decreased within five years after quitting smoking, the researcher added. "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," Hu said.