Geriatric Otology: Population Health and Clinical Implications

Basic Principles of Aging

Aging is commonly viewed as a single process rather than a collection of complex processes. At the simplest, Hazzard's Geriatric Medicine and Gerontology , one of the primary texts for geriatricians, defines aging as, “a process that turns young adults into distinctly less healthy old ones” and is characterized by its coordinated and malleable nature. Aging consists of organ-specific changes and diseases, such as age-related hearing loss and vestibular dysfunction, along with geriatric syndromes, such as frailty and falls, that cross organ systems and disciplines and can complicate diagnosis and treatment. The mechanisms underlying these changes, diseases, and syndromes relate to changes in the body's ability to maintain homeostasis across physiologic systems. This dysregulation involves changes, from the subcellular to the organ level, that result in increased vulnerability to disease. Deficits accumulate over one's life span and manifests as disease. Variable rates of accumulated deficits account for individual differences in biologic versus chronologic age.

Aging is a biologic, psychological, and social process and must be viewed from a life course perspective. For example, as biologic and physical deficits accumulate during the life course, individuals also gain knowledge, skills, and resilience, as well as accumulate behavioral resources and psychological reserves through life experiences. Health and well-being throughout the life course depend on sociodemographic characteristics, environmental and social resources and constraints, individual health behaviors, psychological influences, and biologic pathways. This comprehensive and holistic view of aging and health characterizes geriatrics and gerontology, and the care of older adults, including geriatric otologic care, must broadly reflect these domains. This chapter first reviews current understanding of the state of older adults and aging in the United States and then reviews two common age-related otologic conditions and takes a public health perspective to explore the epidemiology, implications, and emerging approaches needed to address these conditions.

Epidemiology of Aging

Advances in public health have extended life expectancy and translated to a rapidly growing older adult population. In 2011, the first of the Boomer generation began to turn 65 years old, and the proportion of the U.S. population older than 65 years is growing more rapidly than the population younger than 65 years, which reflects decreases in birth rates and reductions in mortality, particularly among the oldest old. From 2010 to 2050, the population of older adults is expected to double from 40 million to almost 84 million older adults, and the steepest increase is expected between 2010 and 2030 when the population older than 65 years will grow to more than 20%.

In addition to aging, the U.S. population is becoming increasingly diverse. When considering the overall population, the United States is expected to become a majority-minority by 2043, when non-Hispanic whites will no longer represent the majority. Among adults 65 years and older, the transition to a majority-minority population is not expected to occur for the next 40 to 50 years. However, the older population will become increasingly diverse over the ensuing decades, and this change emphasizes the need to consider the spectrum of older adults and their varied needs, including those of geriatric otologic patients.

Over the past seven decades, the United States has made enormous strides in the overall educational attainment of older adults. For example, in 1950, only 15.3% of older men had completed 4 years of high school compared with 78.9% in 2010; and women experienced a similar improvement in education level. However, differences in educational attainment by race/ethnicity exist, particularly given that most current older adults received their education prior to the Civil Rights Act of 1964. Such differences in education have significant impact on individual's health and health behaviors, such as hearing health care. Health literacy demonstrates the critical role education can play in health. Considering all demographic age groups within the United States population, older adults by far have the lowest levels of health literacy. Older adults as a group have the highest proportion of persons with “below basic” proficiency, and only 3% of older adults have a “proficient” level of health literacy. Inadequate health literacy is generally accepted as less than a 6th grade reading level, which has important ramifications when the mean reading level of hearing aid manuals and training materials is almost at a 10th grade reading level.

Similar to findings among adults in general, income and rates of poverty vary among older adults by race/ethnicity, but marital status, sex, and age carry added significance. The lowest income levels are among nonmarried African-American and Hispanic older adults and among the oldest, those 80 years and older, and the highest rates of poverty are among African-American and Hispanic women. Although poverty remains a priority in improving the health of older Americans, great improvements have been made in reducing poverty among older adults, with the expansion of social security and the introduction of Medicare, whereas previously more than a third of older adults lived in poverty. For most older adults, social security accounts for the largest share of income, but low-income older adults live almost exclusively on social security. The average monthly benefit to retired workers in 2016 was $1360, in contrast to the average cost of bilateral hearing aids at $4700.

There has been increasing recognition of the value of older adults aging in place, within their homes. The majority of older adults live in the community independently and in a suburban setting and have lived in their homes for at least 10 years. As older adults give up driving and transportation options decrease, particularly for older adults aging in a suburban or rural setting, these have important implications on their ability to seek clinic-based care and resources. As older adults age in place, marital status, specifically living alone, is a risk factor for social isolation and loneliness. The prevalence of older adults living alone is higher among women and increases with age. Geographic and social isolation, along with limited access to community support, may worsen the consequence of age-related hearing loss and vestibular dysfunction.

Functional limitations also greatly influence older adults’ willingness and ability to seek care, as well as their daily lives and health behaviors. The prevalence of functional limitations increases with age, including difficulty running errands alone and difficulty with mobility, such as walking and climbing stairs. Comorbidities also increase with age; the vast majority of adults 65 years and older have at least one chronic condition, and almost two-thirds have two or more competing health concerns. Daily routines filled with guideline-based care can consume hours of an older adults’ time and energy and may limit their ability and willingness to self-manage an additional chronic condition such as hearing loss or vestibular dysfunction.

In addition to increasing limitations of physical function, cognition changes with age. Important racial/ethnic differences exist in how cognitive impairment progresses with age. Almost half of African-American and Hispanic adults 85 years and older are cognitively impaired. Overall, one in three older Americans will die with a diagnosis of dementia. Age-related physical and cognitive changes are highly prevalent among geriatric patients and must inform the delivery of patient-centered otologic care, which traditionally involved mastering new technologies, attending regular clinic visits, and incorporating new health behaviors into daily routines.

Epidemiology of Age-Related Hearing Loss

Nationally representative samples of older Americans estimate that 23 million adults 70 years and older have a clinically significant hearing loss (better ear hearing pure tone average >25 dB HL), which equates to two-thirds of older adults. Age is the primary risk factor for age-related hearing loss, where the prevalence of hearing loss essentially doubles with each decade of life; for example, from a prevalence of 13% among Americans 40 to 49 years old to 29% among adults 50 to 59 years old and up to almost 90% among those 80 years and older ( Fig. 133.1 ). With an aging population, the number of older adults with hearing loss is expected to double and affect almost 50 million older Americans by 2060.

Beyond age, sex is a known risk factor for age-related hearing loss. Nationally representative studies and large prospective cohorts document higher rates of hearing loss among males compared with females, despite controlling for age and occupational noise exposure, with the differences most apparent at higher frequencies. Skin color is another risk factor for age-related hearing loss consistently supported by both nationally representative studies and large prospective cohorts. Skin pigmentation (reflected by skin color, Fitzpatrick skin type, or self-reported race/ethnicity) is correlated with the density of strial melanocytes in the cochlea and is considered protective for age-related hearing loss. Evidence supports differences in melanocytic functioning as a potential underlying mechanism. Cardiovascular risk factors for hearing loss, such as hypertension, diabetes, stroke, and smoking, have equivocal support, and nationally representative studies have not found a consistent significant association between age-related hearing loss and these risk factors.

Despite the prevalence of age-related hearing loss, the current understanding of the epidemiology is based on relatively few epidemiologic studies that include objective audiometric data. Historic prospective cohort studies, such as the Framingham Study and the Beaver Dam Study, provide estimates of the prevalence of age-related hearing loss and associated risk factors, but they are significantly limited in their representation of non-white older adults. The Health ABC Study cohort includes a more diverse sample, with more than one-third of the sample consisting of African-American older adults, and, by design, the National Health and Nutrition Interview Survey (NHANES) provides a nationally representative sample and a closer representation of the U.S. diversity of older adults. Although rates of age-related hearing loss are lower among females and racial/ethnic minorities, the relative lack of epidemiologic data on age-related hearing loss impacts the ability to document and address associated disparities in hearing health care.