Body Fat Linked to Diabetes Risk in Older People

To avoid Type 2 diabetes, seniors may need to watch their weight just as closely as younger individuals do, a prospective cohort study showed....

Among individuals 65 and older, several measures of adiposity and weight gain were associated with a greater risk of developing Type 2 diabetes during follow-up, according to Mary Biggs, PhD, of the University of Washington School of Public Health and Community Medicine in Seattle, and colleagues.

The hazard ratios ranged from 1.9 to 6.0 when broken down by sex.

Self-reported body mass index at age 50 and weight gain from age 50 to study baseline were both also associated with risk of incident diabetes. "We found it surprising that the relationship between adiposity or body fat and diabetes was so strong among older adults," Biggs said.

"I think the results affirm the importance of weight control during middle age and suggest that weight control remains important into older ages in terms of reducing diabetes risks."

Although overweight and obesity are well-recognized risk factors for Type 2 diabetes among young and middle-age individuals, the relationship has not been well studied in older adults, according to the researchers.

So they turned to the Cardiovascular Health Study, which prospectively followed 4,193 men and women who were at least 65 and free of diabetes at baseline from 1989 to 2007. The participants came from four counties in North Carolina, Maryland, California, and Pennsylvania.

At baseline, mean age of participants was 72 and their mean BMI was 26 kg/m2 for both men and women; 45% had prediabetes (fasting glucose of 100 to 125 mg/dL).

Through a median follow-up of 12.4 years, there were 339 incident cases of Type 2 diabetes, defined as use of diabetes medication or a fasting glucose of at least 126 mg/dL.

With increasing quintiles of various measures of adiposity, there was a corresponding greater risk of developing diabetes, with no significant differences by sex or race.

All multivariate models were adjusted for age, sex, race, smoking, alcohol consumption, physical activity, and dietary factors.

The magnitude of the increased risk associated with various measures appeared to fade with age, with about half the risk in individuals 75 and older compared with those 65 to 74. However, the interaction with age was significant only for BMI at age 50 and at baseline and for fat mass.

There are several possible reasons risk might be increased to a lesser extent in older individuals, according to the researchers.

"Among older adults, standard anthropometric measures may not adequately quantify body fat due to age-related changes in body composition, including decreases in skeletal muscle mass and height," they wrote.

In addition, among older individuals, regional fat distribution may be more important in the etiology of diabetes than absolute fat mass, the pathophysiology of diabetes may differ, and selective survival may be involved. Changes in body weight were also associated with diabetes risk.

Compared with individuals who had a weight fluctuation of no more than about 4 pounds, those who gained 20 or more pounds from age 50 to baseline or 13 pounds or more from baseline to the third follow-up visit had a two- to threefold increased risk of developing diabetes.

"Results of this study affirm the importance of maintaining optimal weight during middle age for prevention of diabetes and, while requiring confirmation, suggest that weight control remains important in reducing diabetes risk among adults 65 years of age and older," the researchers wrote.