Researchers from Boston-based Brigham and Women’s Hospital found women with higher caffeine intake have lower risk of tinnitus, described as ear ringing and buzzing.
More than 65,000 women aged 30 to 44 and without tinnitus were recruited in 1991 when the study began. The participants were asked to complete lifestyle and medical history questionnaires every two years and food frequency questionnaires every four years.
After 18 years of follow-up researchers identified 5,289 cases of tinnitus from the questionnaires returned in 2009.
They found that among women who consumed 450-499 mg/d (approximately five 8-ounce cups of coffee per day) the incidence of reported tinnitus was 15% lower compared to women with a low caffeine intake (less than 150 mg/day, approximately one and a half 8-ounce cups of coffee).
The majority of caffeine consumed among the women was from coffee and the results did not vary by age.
“We observed a significant inverse association between caffeine intake and the incidence of tinnitus among these women,” said Gary Curhan, senior author of the study and a physician-researcher in the Channing Division of Network Medicine at Brigham and Women's Hospital.
"The reason behind this observed association is unclear. We know that caffeine stimulates the central nervous system, and previous research has demonstrated that caffeine has a direct effect on the inner ear in both bench science and animal studies," he added.
Researchers noted that further evidence is needed to make any recommendations about whether the addition of caffeine would improve tinnitus symptoms.
American Journal of Medicine
Published online ahead of print DOI http://dx.doi.org/10.1016/j.amjmed.2014.02.033
A Prospective Study of Caffeine Intake and Risk of Incident Tinnitus
Authors: Curhan G. and S., Glicksman, J.