Some types of disability are increasing in older obese Americans, even though recent improvements in cardiovascular health care have reduced the risk of disability in older normal-weight people, according to researchers at the University of Pennsylvania, Philadelphia.
Data from recent studies have suggested that the obese elderly population in the United States may have grown healthier since the 1960s, especially with the widespread use of lipid-lowering and antihypertensive drugs. “If the physiological manifestations of obesity are increasingly treatable, then some of the negative health effects of obesity may be in decline,” and obesity may be becoming less disabling, wrote researchers Dawn E. Alley, Ph.D., and Dr. Virginia W. Chang of the University of Pennsylvania, Philadelphia. On the other hand, they wrote, if improvements in health care are allowing obese people with chronic disease to live longer, then disability may be increasing in this population.
To examine whether the association between obesity and disability has changed over time, they assessed body mass index and disability in subjects aged 60 years and older, comparing data from the National Health and Nutrition Examination Surveys done in 1988–1994 (NHANES III) with data from the NHANES surveys of 1999–2004.
A total of 5,724 subjects from the earlier survey and 4,984 subjects from the later survey indicated whether they had no difficulty, some difficulty, much difficulty, or an inability to perform six tasks: walking one-quarter of a mile; walking up 10 steps without resting; stooping, crouching, or kneeling; lifting or carrying 10 pounds; walking between rooms on the same floor; and standing up from an armless chair. The subjects also reported on their ability to perform three activities of daily living: getting in and out of bed, eating, and dressing.
In the interval between the two NHANES studies, the prevalence of functional impairment did not change among normal-weight subjects, but it increased among obese subjects, from 37% to 42%. In a closer analysis that controlled for demographic characteristics, the odds of being functionally impaired rose 43% among the obese but showed no change among normal-weight subjects.
When the subjects were separated into categories of mild, moderate, and extreme obesity, they found that functional impairment had increased in all three. The overall increase in disability, therefore, was not solely because there are more people in the “extremely obese” category in later years, Dr. Alley and Dr. Chang said (JAMA 2007;298:2020–7).
Several obesity-related conditions were strongly associated with disability, including arthritis, diabetes, heart failure, MI, and stroke.
In an accompanying editorial, Dr. Edward W. Gregg of the Centers for Disease Control and Prevention, Atlanta, and Dr. Jack M. Guralnik of the National Institute on Aging, Bethesda, Md., said the most important finding in this study was that obese patients today are more likely to be disabled than obese patients were a decade earlier.
“This finding contrasts with the general reduction in disability reported for older adults” in the general population, they noted. “The authors speculate that this increased disability may be due to the average obese person of the current cohort having spent more years obese than in previous cohorts” and thus having more cumulative exposure to disability-inducing obesit (JAMA 2007;298:2066–7).
“It is also possible that because of declining mortality rates, the obese segment of the population is now composed of more people with multiple chronic conditions who in previous decades would have died at a younger age,” they wrote.