| Abstract: | Objectives. We examined factors that influence health-related quality of life (HRQOL) among individuals aged 50 years and older with and without functional limitations.Methods. We analyzed data from the 2009 Behavioral Risk Factor Surveillance System to assess associations among demographic characteristics, health care access and utilization indicators, modifiable health behaviors, and HRQOL characterized by recent physically and mentally unhealthy days in those with and those without functional limitations. We defined functional limitations as activity limitations owing to physical, mental, or emotional health or as the need for special equipment because of health.Results. Age, medical care costs, leisure-time physical activity, and smoking were strongly associated with both physically and mentally unhealthy days among those with functional limitations. Among those without functional limitations, the direction of the effects was similar, but the size of the effects was substantially smaller.Conclusions. The availability of lower cost medical care, increasing leisure-time physical activity, and reducing rates of cigarette smoking will improve population HRQOL among older adults with and without functional limitations. These factors provide valuable information for determining future public health priorities.Disability affects a substantial portion of the population, and the prevalence of disabilities increases with age. Adults with disabilities represent 31% of those aged 55–64 years and 52% of those aged 65 years and older.1 Annual disability-associated health care expenditures have been estimated at almost $400 billion, or 27% of all US adult health care expenditures in 2006,2 making this an important economic issue for public health.Disability definitions have evolved over the past 2 centuries because of the medical profession’s changing attitudes regarding health care treatment of individuals with disabilities and changing societal perspectives, including the destigmatization of attitudes and beliefs regarding disability and increased support for designing environments that encourage independent living.3,4 Recently, advocates for a social model of disability5,6 have argued that disability results from functional impairment and limitations that are the result of social, cultural, and environmental factors. Expanding this more integrated conceptualization of disability, the World Health Organization published the International Classification of Functioning Disability and Health (ICF) in 2001.7 The ICF depicts disability as resulting from the interaction of a person’s functional impairment with environmental factors to create limitations. The ICF provides a framework for considering health and disability at the individual and population level across the entire lifespan and provides an important step forward for assessing the relationships among disability, environment, and health outcomes.The shift in focus in public health to health promotion and quality of life is advancing quickly because of increases in life expectancy and the increasing number of individuals living with chronic diseases. Furthermore, as the population of the United States continues to age, the public health community has become more focused on understanding how to improve health-related quality of life (HRQOL) among individuals with multiple chronic conditions and disabilities.8 HRQOL is a multidimensional population health outcome that supplements more traditional measures of mortality and morbidity and is useful because it provides broad summary measures of perceived health.9,10 HRQOL constructs include measures of physical health, mental health, and social functioning.11,12 These measures have the potential to bridge boundaries between disciplines and among social, mental, and medical services. For example, Health and Human Services’ Healthy People 2020 initiative has provided overarching goals that emphasize the desire to create high quality lives for individuals with disabilities, including the creation of social and physical environments that promote optimal health, and has recommended the use of HRQOL measures to assess progress in this area.13When depicting the nature of the relationships among disability, functional limitations, and HRQOL, it is important to consider the perspective of the individual evaluating the health outcome. Previous studies have shown significant differences between self-report and proxy reports for individuals with disabilities.14,15 For example, 1 study found that more than 50% of adults with serious and persistent disabilities reported good or excellent HRQOL despite living a daily life that other individuals might regard as less than optimal.15 This apparent contradiction between self-reported health and assessment of health by others was named “the disability paradox.” This paradox emphasizes the importance of self-report for determining HRQOL. The disability paradox can be explained, in part, by the fact that quality of life and well-being do not involve merely the absence of illness and disability. Indeed, many people with disabilities or illness experience a fine quality of life, and, conversely, many who are not ill or infirm still do not flourish. Furthermore, although self-report is generally the preferred method for measuring HRQOL,10,16 another concern in measuring HRQOL among people with longstanding functional limitations is that some popular measures of HRQOL include function domains in their summary measures of HRQOL. Consequently, these measures will reduce scores of HRQOL related to functional limitations among those who may otherwise perceive their HRQOL to be very good, resulting in an HRQOL score that is artificially low.17,18 This concern has been documented for the Rand Medical Outcomes Study Short Form–36 health survey as a measure of HRQOL19 derived from differential item analyses. These differential item analysis estimates appear to be smaller for the Centers for Disease Control and Prevention (CDC) Healthy Days measures of HRQOL.20In a seminal article on understanding the structure of perceived health (more recently referred to as HRQOL) among older Americans, Johnson and Wolinsky21 developed a conceptual and statistical model to understand the relationships among 4 primary components of health: disease, disabilities, functional limitations, and perceived health. As part of their causal model, functional limitations are considered, in part, to result from disabilities and are a useful way for classifying how a particular disability has affected an individual.22Measuring HRQOL can assist in determining the burden of disabilities and chronic diseases and can provide valuable new insights into the relationships between HRQOL and risk factors. We investigated which risk factors and public health policies should be considered for improving HRQOL among those with and those without functional limitations. On the basis of the conceptual definitions the ICF presented, the theoretical model presented by Johnson and Wolinsky,21 and the health services model of Andersen,23,24 we assessed the associations between HRQOL and predisposing factors (age, race/ethnicity, and marital status), enabling factors (health care coverage, medical care cost issues, and health care utilization), and modifiable health behaviors (smoking, nutrition, and leisure-time physical activity) among individuals aged 50 years and older with and without functional limitations. We derive our definition for functional limitations from Healthy People 2010 surveillance objectives. The definition represents the standard questions and classifications used for the CDC Behavioral Risk Factor Surveillance System (BRFSS). This definition combines general limitations in function owing to disability or health conditions and adds the use of assistive technology to capture those who may not report limitations because these aids obviate the body limitation. Asking respondents about attribution to disability and health conditions especially helps include older adults with disability, who might otherwise ascribe their limitations to aging. We hypothesized that poor HRQOL would be associated with lower rates of health care coverage, difficulties with cost for medical care, higher smoking rates, poor nutrition, and less leisure-time physical activity. We also hypothesized that the factors that influence HRQOL would differ for those with functional limitations from those without. On the basis of the results of these analyses, we have identified promising future directions for public health prevention and research. |
