Prevalence and Characteristics of Tinnitus among US Adults
From: Am J Med. 2010 Aug;123(8):711-8
Tinnitus, derived from the Latin word tinnire meaning “to ring,” is the perception of noise in the absence of an acoustic stimulus. It is a common condition that is usually subjective, perceived only by the patient, and therefore diagnosis and monitoring rely on self-report. Data from the 1996 National Health Interview Survey (NHIS) showed tinnitus was experienced by approximately 35-50 million adults in the US, with 12 million seeking medical care, and 2-3 million reporting symptoms that were severely debilitating. Cases and proposed etiologies of tinnitus are clinically heterogeneous and, although several treatment options have been tried, no single cure exists for the condition.
Patients who experience tinnitus often report significant associated morbidities. Lifestyle detriment, emotional difficulties, sleep deprivation, work hindrance, interference with social interaction, and decreased overall health have been attributed to tinnitus. Although causative relations are yet unknown, patients with tinnitus can have increased risk for depression, anxiety, and insomnia.
A limited number of risk factors for tinnitus have been suggested, the best described of which include increasing age, hearing loss, and loud noise exposure. These associations merit further exploration in a large cohort. Furthermore, the relations between tinnitus and other demographic and health factors are minimally characterized in the current literature. Therefore, the authors examined the relation between tinnitus and several potential risk factors using data from the National Health and Nutrition Examination Survey (NHANES), a large nationally representative survey.
The overall prevalence of tinnitus in the US was 25.3%, corresponding to a national estimate of 50 million adults. This prevalence is consistent with the upper range of the overall estimate previously reported from the NHIS (35-50 million). Similar to data from the Beaver Dam cohort, the prevalence of tinnitus in our study increased with age until the age of 60-69 years, after which it decreased with increasing age. This inverse relationship between age and tinnitus in older age groups has been demonstrated in several previous studies. One possible mechanism for this observation is that tinnitus may be associated with other conditions that confer a selective mortality disadvantage among individuals with tinnitus. The possibility also exists, however, that late symptomatic improvement may be part of the natural history of tinnitus.
The results of this study showed that non-Hispanic blacks and Hispanics had lower prevalence of any and frequent tinnitus than non-Hispanic whites. Although decreased prevalence in hearing loss has been reported previously in non-Hispanic blacks and Hispanics compared with non-Hispanic whites, this study is the first to report this association between race/ethnicity and tinnitus. The fact that significant associations between race/ethnicity and tinnitus were maintained in participants without hearing impairment suggests a mechanism for tinnitus that is independent of hearing impairment.
The significant associations between tinnitus and smoking and hypertension in this study suggest that vascular disease might have a greater contribution to the etiology of tinnitus than previously reported. Associations between cigarette smoking and hearing loss have previously been suggested, but data on the association between smoking and tinnitus remains scant. The data from the authors showed that current and past smoking confer increased odds of experiencing tinnitus. Although multiple past studies have analyzed the relation between cardiovascular disease and tinnitus, information on the association between hypertension and tinnitus has, up to now, been limited to cases of pulsatile tinnitus from vascular etiologies. These cases likely represent a minority of patients with tinnitus, as most patients with tinnitus present with subjective, sensorineural tinnitus.
Loud noise exposure is generally considered an important risk factor for developing tinnitus. In this study, history of leisure-time, occupational, and firearm noise exposure were all associated with increased odds of tinnitus. The relation between noise exposure and frequent tinnitus, however, differed depending on the presence or absence of hearing impairment. Occupational noise exposure was associated with increased odds of frequent tinnitus in participants with hearing impairment, while leisure-time noise exposure was associated with increased odds of frequent tinnitus in participants without hearing impairment. Occupational noise exposure has been reported to be strongly associated with both tinnitus and hearing loss, possibly due to its chronic effects on inner hair cell, outer hair cell, and acoustic nerve function. However, after an acute acoustic trauma, tinnitus is reported in the initial stages in 90% of the cases, and often persists even when the hearing loss is temporary. The differential vulnerability of cochlear and central components to duration and intensity of noise exposure may explain the variability between tinnitus and hearing loss in noise-exposed subjects.
These results demonstrate an important relation between tinnitus and mental health, as both anxiety and major depressive disorder were associated with increased odds of tinnitus. Participants with a history of either major depressive disorder or generalized anxiety disorder had greater than twice the odds of reporting any tinnitus compared with those not affected by these disorders. In addition, participants with a history of generalized anxiety disorder had >6 times the odds of reporting tinnitus compared with unaffected participants. Although this study is the first nationally representative study to find an association between tinnitus and mental health disorders, numerous smaller studies have reported similar associations. The cause for these associations is not yet known. Tinnitus can result in sleep deprivation, decreased work productivity, and overall lifestyle detriment. These factors might cause psychological distress and bring about or worsen symptoms of anxiety and depression. Major depressive disorder and generalized anxiety disorder, on the other hand, may exacerbate tinnitus, and their treatment might alleviate tinnitus.
Several strengths and limitations of this study should be considered. Data from NHANES is comprehensive and nationally representative, drawing from a large and diverse sample of participants. The study is, however, cross-sectional, making causative relationships impossible to determine. Tinnitus is most often a subjective complaint without a means of objective diagnosis. Therefore, comparisons between participants and studies are difficult. But, during the period of this study, consistency was maintained in assessing the presence and quality of tinnitus among participants.
In conclusion, these results offer insight into the prevalence of tinnitus and identify potentially vulnerable groups. We have demonstrated that, although the prevalence of tinnitus is generally higher at older ages, it also is frequently reported in young adults. Likewise, the potential risk factors for developing tinnitus are significant even in the younger adults. Therefore, opportunities may exist to prevent tinnitus, starting at a younger age. As no known cure exists for tinnitus, it is important to investigate potentially modifiable risk factors for tinnitus. Future research should examine the prospective relations between smoking, hypertension, noise exposure, and mental health conditions and tinnitus.
Clinical Significance:
•Tinnitus is a very common and potentially disabling condition, but few risk factors for its development are currently known.
•The relations between tinnitus and other demographic and health factors are minimally characterized in the current literature.
•Because tinnitus currently has no known cure, identifying potentially vulnerable groups and establishing potential risk factors in a large, nationally representative study is important for decreasing the burden of this condition.
