Being Sedentary Doubles the Mortality Risk for Women

Antoaneta Sawyer, Ph.D.

As I frequently state in my articles on metabolic syndrome and obesity-body mass index (BMI) is an important marker for people who are either overweight or obese and especially who are aging.

Resent article published on line (January 27) in the Journal American Geriatric Society postulates that “the BMI may be overly restrictive for older people, who tend to have obesity as a consequence of decreased metabolism due to aging.”
Obesity is known as the global 21st century epidemic that affects people of both sexes and it is more prevalent in advanced age. We already know its negative consequences on preliminary aging and mortality.

The study goal was to assess all-cause and cause-specific mortality associated with underweight (BMI, <18.5),>Health in Men Study and the Australian Longitudinal Study of Women's Health, 4677 men and 4563 women aged 70 to 75 years were selected in 1996 and followed up for up to 10 years. The study outcomes were to find out what is the relative risk for all-cause mortality and specific mortality related to cardiovascular disease, cancer, and chronic respiratory disease.

Astonishingly enough the researchers concluded that overweight elderly have similar mortality to normal-weight elderly (Flicker, 2010). The overweight participants had lowest mortality risk, with risk for death for overweight participants 13% less than for normal-weight participants (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.78 - 0.94). Obese and normal-weight participants had similar risk for death (HR, 0.98; 95% CI, 0.85 - 1.11). Across all levels of BMI, being sedentary doubled the mortality risk for women (HR, 2.08; 95% CI, 1.79 - 2.41) but was associated with only a 28% greater risk for men (HR, 1.28; 95% CI, 1.14 - 1.44).

Author’s conclusions were the following, “Overweight older people are not at greater mortality risk, than those who are normal weight, and there is little evidence that dieting in this age group confers any benefit; these findings are consistent with the hypothesis that weight loss is harmful."

Despite the study has few limitations and for example e.g. the design of this study is purely observational, lack of generalization to older people who are oldest old and frail and at risk for death, measurement of height and weight only once at study entry, use of BMI as a surrogate measure of body fat, reliance on self-reported height and weight, Leon Flicker believes that “These results lend further credence to claims that the BMI thresholds for overweight and obese are overly restrictive for older people," and that “Being sedentary is associated with significantly greater risk of mortality in women than in men. Of course, a greater risk was found for extreme “morbid” obesity, when the study author concludes, "Mortality risk must be balanced by the potential loss of physical function associated with morbid obesity”.

Reference:

Leon Flicker et al. Overweight Elderly Have Similar Mortality to Normal-Weight Elderly. J Am Geriatr Soc. Published online (January 27, 2010); Print publication 2010, 58, 234-41.