Occupational Health and Safety Risks for the Aging Worker
Figure 24.2 Past, current, and projected median age of the US civilian labor force by gender, race, and ethnicity .
In addition to the aging of the baby-boom generation, other factors also underlie aging of the US workforce . The global population is aging; life expectancy has increased; and fertility rates have decreased. Furthermore, the economic downturn and changing policies related to retirement and benefits are causing older workers to stay in the workforce longer. 24.3 Health and Safety Risks of Older Workers
Exposed to Occupational StressorsAge-related changes in behavior and physiological and cognitive function are important factors in characterizing the risks posed to older individuals in occupational settings. While the majority of these age-related changes may most appropriately be described as declines in function, the aging population is a highly heterogeneous group, demonstrating significant variability in functional capacity. Chronological age does not accurately predict biological age, as declines in physiological and cognitive function are greatly influenced by genetics, nutrition, disease, medications, exercise, and other environmental factors [3, 4]. Nonetheless, approximately two of three Americans aged 65 years or older cope with multiple chronic health conditions, including arthritis, diabetes, asthma, chronic obstructive pulmonary disease (COPD), and heart failure . These diseases, as well as risk factors contributing to the development of chronic disease, significantly impact an individual’s ability to remain in the workforce and avoid work-related illness and injury. Additionally, in characterizing occupational health risks in older workers, it is important to recognize that early-and mid-life environmental and occupational exposures may affect the response of an individual to occupational stressors later in life. While some early-life exposures have a cumulative effect on a given health response or outcome, others may predispose an individual to experience more overt adverse responses from subsequent occupational exposures later in life [6-12]. Though not unique to the aging population, active members of the workforce are generally healthier than similarly aged non-working adults. In what is commonly referred to as the healthy worker effect, this phenomenon frequently confounds cross-
sectional epidemiologic studies that compare morbidity and mortality rates in workers with those of the less healthy general population, resulting in the appearance of lower rates in workers despite their potentially hazardous environmental or occupational exposures . The challenge to maintain better-than-average health in older workers, who constitute a substantial and growing at-risk population, is an important one and underscores the need to better understand the special occupational and safety risks faced by aging workers. These risks vary by occupation and industry and may be differentially influenced by disparate prevalence rates of chronic health conditions among older workers across industry sectors . While the greatest number of older adults are employed in manufacturing, retail, financial services, professional and business services, and educational and health services , the percentage of the labor force comprising workers aged 55 years and older is increasing in the majority of industry sectors (Table 24.1). 24.3.1 Occupational Chemical ExposuresAge-related changes in pulmonary function, body composition, hepatic volume and blood flow, xenobiotic metabolizing enzyme activity, and renal function affect the absorption, distribution, metabolism, and elimination of occupational toxicants that may alter the biologically effective dose reaching target organs in older adults [16, 17]. Further, these effects may be exacerbated by pre-existing chronic health conditions as well as myriad pharmaceutical agents used to treat these conditions . Consequently, similar exposures between younger and older adults may result in significantly different internal doses and total body burden of hazardous occupational pollutants. 24.3.2 Musculoskeletal Risk Factors
Loss of muscle mass and strength with age influences physical work capacity in older adults and increases the risk of muscle fatigue and falls . Combined with an age-related decrease in bone mineral density and architectural deterioration of bone, particularly among postmenopausal women, these falls increase the risk of bone fractures in older workers . In addition, owing
to declines in muscle strength, ligament elasticity, and joint and cartilage degeneration, older workers are potentially at increased risk of other work-related musculoskeletal disorders [21, 22]. 24.3.3 Hearing LossThe aging population is at high risk of developing hearing loss from both the normal aging process (presbycusis) and from nonoccupational noise sources, with a well-established monotonic increase in the prevalence of hearing loss with increasing age . While the most common occupational risk factor for hearing loss is noise exposure, occupational exposure to chemical solvents may also contribute to occupationally induced hearing loss [24-26]. Whatever the cause, hearing loss may have significant safety and work performance implications for the aging workforce, as multiple investigators have observed an increase in the risk of occupational injuries among workers with impaired hearing [27-30]. 24.3.4 Visual ImpairmentAs with hearing loss, decrements in visual function are extremely common in older adults due to a normal loss of visual acuity as well as prevalence of age-related eye diseases, including glaucoma, cataract, and macular degeneration . Though the epidemiologic evidence of an association between decrements in visual function and occupational injury is equivocal , impaired vision must be considered when evaluating potential risk factors in the workplace [30, 33]. 24.3.5 Cognitive FunctionSimilar to physiological function, age-related change in cognitive performance is characterized by a high degree of interindividual variability [34, 35]. However, in general, declines in recall, real-time processing, and novel problem solving (i.e., episodic memory and fluid intelligence) are observed with increasing age. On the other hand, maintaining acquired knowledge and processing familiar information (i.e., scientific memory and crystallized intelligence) tend to incrementally increase with age until beyond the age of
50 [35-38]. Although it would seem reasonable to speculate that age may be negatively associated with work performance due to cognitive decline, this has not been conclusively substantiated in the scientific literature. In addition, there is little empirical evidence demonstrating increased occupational health and safety risks among older adults due to a decline in cognitive ability or performance [27, 36]. Studies evaluating age-related change in cognitive function as a risk factor for occupational accidents have generally observed that declines in perceptual processing and decision making may be offset in older workers by experience and expertise [27, 39, 40]. However, the degree to which acquired skill and knowledge may compensate for age-related changes in cognitive function has not been extensively studied and is likely to vary greatly by occupation . 24.3.6 Age-Related Differences in Occupational Illness
and InjurySomewhat paradoxically, older workers who, for the reasons described in the preceding text, are more susceptible to adverse health effects resulting from exposures to occupational stressors, experience lower rates of occupational illness and injury compared to younger adults [2, 36, 41]. Although not completely understood, this may be explained in part by age-related advantages in experience and expertise, safety and health awareness, motivation, and opportunities for employment in lower-risk, that is, managerial and administrative, occupations. However, there is a positive association between age and time away from work as a result of occupational illness or injury, signifying that relative to their younger counterparts older workers tend to experience more severe occupational illness and injury and require more time for recovery (Fig. 24.3) [2, 42, 43]. It would therefore reasonably follow, and has been consistently demonstrated, that older workers experience higher rates of fatal injuries in the workplace relative to younger workers [36, 44]. 24.4 Importance of Prolonging the Work Ability
and Wellness of Older WorkersMaintaining the health, wellness, and work ability of older workers is an increasingly important priority [2, 45]. There are important
reasons for this. Older workers are becoming a progressively greater part of the workforce. Thus, maintaining their ability to work productively and effectively-“work ability”—is critical to older workers and to their employers. Work ability reflects the balance between a person’s resources (e.g., health, functional abilities, education, competence, values, attitudes) and work demands. A questionnaire-based work ability index was initially developed in Finland but has now been used in many countries. Early studies of municipal em-ployees over 45 years of age showed that, over an 11-year period, the work ability index declined significantly in 30% of workers, re-mained relatively unchanged in 60%, and improved among 10%. Factors related to management, ergonomics, and lifestyle were as-sociated with both decline and improvement. A better work abil-ity index has been associated with a longer work life and improved quality of a person’s active period after retirement . Thus, there might be great benefit realized through interventions to preserve work ability.