Annals of Long Term Care

Roughly two-thirds of American adults are “overweight” or “obese” by World Health Organization (WHO) standards, which defines these terms, along with “normal weight” and “underweight,” based on body mass index (BMI).

While studies have found that younger adults who meet the WHO criteria for “overweight” and “obese” run higher risks of serious health problems and mortality than their “normal weight” cohorts, whether the same is true of older adults has been less clear. Some research, in fact, has suggested that being overweight in later life may lower mortality risk.

A large-scale, long-term study in February’s Journal of the American Geriatrics Society—a study with implications for clinical care—sheds much needed new light on the matter.

The study’s lead author, Leon Flicker, MB, BS, PhD, FRACP, and colleagues, studied more than 9200 Australian men and women, all between age 70-75 years at the start of the study, for ten years or until death, whichever was sooner. After taking into account health, lifestyle, and other potentially confounding variables, the researchers found that “overweight” older adults had a lower risk of death from all causes, and from heart disease, cancer, and respiratory disease, than those meeting WHO criteria for “normal weight,” “underweight,” and “obese.” Overall, older adults who were categorized as “overweight” had a 13% lower 10-year mortality rate than those classified as “normal weight.”

"Concerns have been raised about encouraging apparently overweight older people to lose weight, and as such, the objective of our study was to examine the major unresolved question of 'what level of BMI is associated with the lowest mortality risk in older people?'" says Dr. Flicker, of the University of Western Australia. "These results add evidence to the claims that the WHO BMI thresholds for overweight and obese are overly restrictive for older people. It may be timely to review the BMI classification for older adults.”

The clinical implications: Weight loss does not appear to be a healthy goal for “overweight” older adults, and may actually be harmful. However, exercising regularly does seem to be a healthy goal in later life, regardless of weight. Being sedentary, the researchers found, boosted 10-year mortality rates 25% for the men in the study and doubled it for women.

To help older adults start and continue exercise regimens that are right for them, the American Geriatrics Society (AGS) Foundation for Health in Aging (FHA) has published an easy-to-understand resource on exercise in later life. The Physical Activity Resource, found at www.healthinaging.org/agingintheknow/chapters_ch_trial.asp?ch=11, is just one of the helpful offerings on the FHA’s Aging in the Know website, www.healthinaging.org/agingintheknow. The website includes a wealth of health information for older persons, and all content can be downloaded, printed, and shared at no cost.