Many people happily welcome the prospect of a longer life but with one, not so small condition: “So long as I am healthy!” Now a new study of elderly Americans finds that, no matter your race or gender, the number of years in which you may expect to live disability-free is on the rise.

Understanding that an increasing number of people have been living longer, researchers from Harvard University and the National Bureau of Economic Research decided to examine whether the extra time is quality time, so to speak: has disability and morbidity increased along with lifespan?

One of the primarily difficulties when attempting to assess these factors is that seniors live diverse lives: some live with their children, others in institutions, and still others on their own. Most studies dwell on one group or another, which may significantly skew the results. Another issue when surveying seniors is that ‘health’ may be defined in different ways. Should the research simply assess whether seniors are living disease-free? Or should physical functioning be included in the evaluation? Finally, timing is an important but problematic issue in any discussion of health. Diagnosis of a life-threatening illness in the final year of life is very different from receiving the same diagnosis much earlier; how can this be measured when considering the health of the elderly?

Taking all of these considerations into account, the researchers decided to use the Medicare Current Beneficiary Survey (MCBS), as they believed it would be most representative. Because of the large sample size, with over 10,000 individuals annually, the MCBS allowed for a comprehensive view of the elderly population between 1991 and 2009 while also including morbidity measures during that same period.

Daily Living

Most senior care providers categorize “activities of daily living” (ADL) as basic, routine tasks that people need to perform each day. Being able to do so, without assistance, is not only a measure of physical function but also a measure of well-being. Generally, health professionals consider these essential tasks to consist of eating, bathing, brushing teeth, dressing, walking, and more. Another set of tasks is known among professionals as “instrumental activities of daily living” (IADL) and this list of less basic though very necessary duties of self-care generally includes preparing meals, maintaining the home, managing finances, shopping, using the telephone, and using transportation.

The researchers found that among seniors during the years from 1991 to 2009, the incidence of very severe impairments — limitations in ADLs or IADLs — fell for those not near the end of life, as did the more severe functional limitations.

“People have more diseases than they used to, but the severe disablement that disease used to imply has been reduced,” the researchers wrote. So, despite the fact that overall disease prevalence may be rising and that many seniors experience less severe functional limitations, such as the ability to bend or kneel, more people are living more years in which they can perform ADL and IADL without assistance.

“Our major conclusion is that time spent in poor physical functioning is being increasingly compressed into the period just before death,” the researchers wrote.

Specifically, they found about 80 percent of seniors near death have at least one major condition, yet this percentage has been relatively constant over the time of the study. The most common major disease is heart disease (38 percent), while cancer affects about 25 percent, as does Alzheimer’s disease, pulmonary disease, and the recoverable acute conditions of heart attack and stroke.

General Improvement

Similarly, functional limitations (bending, for instance, or kneeling) remained relatively constant over time, declining by only 2.7 percent between 1991 and 2009. However, the prevalence of people living with ADL or IADL impairments declined quite dramatically: 22 percent, between 1991 and 2009, with somewhat greater declines for ADL disability than IADL disability. Furthermore, the authors found that this decline in disabled life expectancy was similar across all races, though greater for women than for men. That said, men are also living disability-free for longer.

Disease-free survival increased among seniors during the years between 1991 and 2009 as well, although so did survival with a major disease. Of the total increase in life expectancy of 0.7 years that occurred during the studied period, 0.6 years was associated with disease-free survival while 0.1 years was associated with additional life with major disease.

Considering the positive gains in disability-free life and disease-free survival, the authors questioned why this has occurred. “How much of this trend is a result of medical care versus other social and environmental factors?” the authors wrote. Acknowledging the current results do not speak to this issue, they suggest questions of causality be pursued in subsequent research.

 

Source: Cutler DM, Ghosh K, Landrum MB. Evidence for Significant Compression of Morbidity In the Elderly U.S. Population. National Bureau of Economic Research. 2013.