Overweight Adults Over 70 Have Lower Mortality Risk Than Seniors Of “Normal” Weight?
January 28, 2010
According to a new study published today in the Journal of The American Geriatrics Society, adults over 70 years who are classified as overweight are less likely to die over a 10-year period than adults who are in the normal weight range—results that question certain popularly held beliefs about weight. Researchers looked at data taken over a decade among more than 9,200 Australian men and women between the ages of 70 and 75 at the beginning of the study, who were assessed for their health and lifestyle as part of a study into healthy aging. (Australia is ranked the third most obese country, behind the United States and the United Kingdom.) Obesity and overweight are most commonly defined according to body mass index (BMI). The World Health Organization (WHO) defines four principal categories—underweight, normal weight, overweight and obese—the limits for which were primarily based on evidence from studies of morbidity and mortality risk in younger and middle-aged adults. Researchers say it’s unclear whether the overweight and obese cut-off points are overly restrictive measures for predicting mortality in older people. The Australian research uncovered that mortality risk was lowest for participants with a BMI classified as overweight—it was in fact 13 percent lower than for those with normal weight. The benefits were only seen in the overweight category, not in those people who are obese. "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?'" said lead researcher Professor Leon 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. Our study suggests that those people who survive to age 70 in reasonable health have a different set of risks and benefits associated with the amount of body fat to younger people, and these should be reflected in BMI guidelines." Separately, it’s worth noting that, while the same benefit in being overweight was true for men and women, being sedentary doubled the risk of death for women, whereas it only increased the risk by a quarter in men. Being overweight is one thing, but not getting exercise swings the pendulum far in the other direction, at least for women.