Obesity after the age of 70 may not shorten a person’s life, but it may lead to more years of disability, a study shows.

Researchers found that among more than 7,100 U.S. adults age 70 and older, those who were obese had a life expectancy comparable to their leaner peers’. However, obese men and women spent more of their later years with some physical disability.

It’s unclear why Obesity does not seem to affect older adults’ life expectancy despite its link to greater physical limitations, according to the study’s lead author, Dr. Sandra L. Reynolds of the University of South Florida in Tampa.

The findings, she told, may reflect a “survivor effect.” That is, Obesity and its related ills may increase the risk of death at younger ages, while obese adults who reach the age of 70 and beyond may be no more likely to die than their thinner peers.

Also uncertain are the reasons for the greater disability found among obese elderly, according to Reynolds. She said she suspects one factor may be chronic inflammation in the body, a state thought to contribute to illnesses such as Heart disease. Obesity is also a risk factor for arthritis of the knee and hip, potentially disabling conditions.

Obese adults in the study did have high rates of High Blood Pressure, Diabetes and Arthritis, Reynolds and her colleagues note in a report published in the journal The Gerontologist.

The researchers based their findings on data from a study that followed 7,132 men and women age 70 and older for about 5 years. Overall, obese adults were somewhat less likely to die during the study period, but were more likely to develop a limitation that kept them from performing daily tasks.

For example, a 70-year-old woman could expect to live another 15 years, regardless of her weight. But, on average, an obese woman spent more than 7 of those years disabled, while leaner women suffered from a disability for less than 5 years. Similar differences were seen among men.

Few studies, Reynolds and her colleagues write, have looked at ways to reduce Obesity among older adults. But finding effective ways to do so, they conclude, “could have a major impact on disability rates in older adults.”

SOURCE: The Gerontologist, August 2005.