June 23, 2010 -- Obesity and weight gain increase the risk for diabetes in the elderly, but the association is not as strong after age 75 as it is for younger adults, a new study finds.
Researchers followed people over age 65 for more than a decade in one of the largest and longest studies ever to examine the impact of obesity and weight gain on diabetes risk in the elderly.
Overall, people in the study who weighed the most were two to six times as likely to develop diabetes during the follow-up as people who weighed the least.
People who were obese at age 50 and gained 20 pounds or more prior to entering the study were five times as likely to develop diabetes as people who were not overweight and did not gain weight.
The study appears in the June 23/30 issue of the Journal of the American Medical Association.
“We already knew it was important to maintain an optimal weight to lower diabetes risk, and this study finds that it remains important into old age,” lead researcher Mary L. Biggs, PhD, of the University of Washington, Seattle, tells WebMD.
The study included 4,193 adults aged 65 and older (median age was 73) followed for an average of 12.4 years. During the follow-up, 339 new cases of diabetes were identified.
Biggs and colleagues examined several measures of obesity, including body mass index (BMI) at study entry, BMI at age 50, weight, waist circumference, and waist-to-hip ratio.
All of these measures were strongly related to diabetes risk, as was weight gain after age 50, Biggs says.
Compared to people whose weight remained relatively stable, people who were normal weight before age 50 and who gained 20 pounds or more after age 50 and before entering the study had a threefold greater risk for developing diabetes during the follow-up.
Diabetes risk was four times greater for study participants who had the highest BMIs and biggest waist circumferences.
Compared to people whose waist size remained relatively unchanged, people whose waist grew by more than 4 inches over the follow-up period had a 70% higher risk of developing diabetes.
Among people older than 75 when they entered the study, those who were overweight or obese were twice as likely to develop diabetes.
“Obesity-associated risk does seem to wane some as people get older,” Biggs says. “But the important message was that there was still a relationship.”