Risk Factors Contributing to Sensorineural Hearing Loss in Adults
Hearing loss is one of the most common problems in adults over 50 years of age. The National Institute of Aging estimates that 35% of adults between 65 and 74 years old have significant hearing loss. About 15% of the 45 to 64 year-old group have hearing loss.
Factors contributing to hearing loss include noise exposure, ototoxic drugs, cardiovascular disease, smoking, family history of hearing loss and aging.
It is difficult to determine the effects of age on hearing separate from other factors. Wiley, et al. (2001) attempted to do so in a study of 355 individuals between the ages of 48 and 65 years. The authors also reviewed previous investigations of known factors.
Several studies of adults investigated hearing in individuals living in relatively noise-free cultures. In general, these individuals have better hearing than their counterparts in industrialized societies. However, even in these noise-free environments, older adults have more hearing loss than younger adults.
A number of studies have found a link between cardiovascular disease and hearing. For example, a study of 1200 men found that men classified as borderline hypertensive were 32% more likely, and those with systolic blood pressure of 160 mm Hg or greater were 74% more likely to have significant hearing loss.
Smoking has been implicated to have an effect on hearing loss in a number of investigations. In a study of nearly 4000 individuals, Cruickshanks et al. (1998) found smokers are 1.7 times more likely to have significant hearing loss.
A family history of hearing impairment has long been identified as a high risk factor for congenital hearing loss and for age-related hearing loss.
Gender has a small but significant effect on hearing at certain frequencies. The researchers cautioned that noise exposure may not have been accounted for sufficiently. Recreational noise exposure may have contributed to the gender effect if men are exposed to more recreational noise than women.
Aging appears to have a small but significant effect on hearing, even when other known factors are absent. For both men and women, hearing thresholds for the 56 to 65 years old group were 5 to 10 dB poorer than for the 48 to 55 year old group. There was a clear tendency for the greater effect to occur in the higher frequencies, which are more related to speech clarity than speech loudness.
These data suggest that aging is a contributing factor to hearing loss even when other known factors are absent. Men have slightly poorer high-frequency hearing than women, although part or all of this difference may be due to unreported exposure to toxic noise levels.
Role of Primary Care Physician
The primary care physician is the most important source of information about hearing healthcare, according to a survey of more than 3,500 adults commissioned by the American Academy of Audiology.
Nearly two-thirds of respondents with acknowledged hearing loss listed their primary care physician as their most important source of information about their hearing healthcare needs. Family/friends were a distant second, with 38% listing them as an important source of information.
“The primary care physician is the most important source of information about hearing healthcare.”
The American Academy of Family Physicians has highlighted the need to identify patients with hearing loss. The Family Physician Panel of the Better Hearing Institute recommends that hearing screening be part of regular physical examinations. The U.S and Canadian Preventive Services recommend hearing screening of all patients age 55 or older.
The National Council on the Aging concluded:
“Physicians and other healthcare providers should encourage older people who are suspected of having a hearing loss to seek appropriate screening, diagnosis and treatment.”
The Physician Referral
Physician-referred patients are eight times more likely to be successful hearing aid users than those not physician-referred. Positive recommendations are especially important because of the common tendency for individuals to deny the presence of hearing loss, or to minimize its impact on themselves and their family.
Audiology Healthcare News Winter 2014.