Later Diabetes Risk Rises With Midlife Weight Gain, Measures of Central Adiposity

June 25, 2010

June 25, 2010 (Chicago, Illinois) Weight gain as well as familiar, easily obtained measures of central adiposity in middle-aged and elderly adults can point to increased risk of developing diabetes in later years, both overall and in both women and men specifically, suggests a prospective analysis based on the participants in the Cardiovascular Health Study [1].

In a cohort of more than 4000 people drawn from four communities across the US who were followed for a median of about 12 years, body-mass index (BMI), weight, fat mass, and waist-to-hip ratio and waist-to-height ratio at age 65 were significant predictors of incident diabetes. "For each measure, there was a graded increase in the risk of diabetes, with increasing quintiles of adiposity," write the authors, led by Dr Mary L Biggs (University of Washington, Seattle), in the June 23/30, 2010 issue of the Journal of the American Medical Association.

The hazard ratio for incident diabetes ranged from about 2 to 6 for participants in the highest compared with the lowest quintile for each separate measure of adiposity for the entire population. Interestingly, the risk increase remained significant but was attenuated for the oldest participants, those >75 years.

"We've known from a number of really large studies that adiposity is related to the risk of diabetes in young and middle-aged adults, but there really was very limited information in the older groups. I think most people assumed that the relationship was the same, but we weren't entirely sure," Biggs told heartwire . "There was some preliminary evidence, but I think this is a more comprehensive look."

She said the current analysis "reaffirms" that weight gain during middle age ups the risk of later diabetes, "and the results also suggest that maintaining an optimal weight during older age is important for minimizing the risk of diabetes at older ages."

The group prospectively followed changes in measures of body fat and its distribution (based on anthropometrics and bioimpedance data) in 4193 men and women aged 65 years or older at baseline and at three-year intervals. The participants, from communities in North Carolina, Maryland, California, and Pennsylvania, were enrolled from 1989 to 1993 and followed until 2007. Incident diabetes, identified in 339 participants, was defined as use of diabetes medications or a fasting blood glucose >126 mg/dL.

"It didn't really matter which measure we looked at, the people in the highest 20% in the distribution of each of these measures had an increased risk of diabetes compared with those in the lowest," Biggs said. That was true overall and for women and men separately.

Hazard Ratio* (95% CI) for Risk of Incident Diabetes, Highest Quintile of Adiposity Measures vs Lowest Quintile

Adiposity measure Women, n=2457 Men, n=1736 All participants
BMI 3.7 (2.3-6.2) 5.6 (2.7-11.4) 4.3 (2.9-6.5)
BMI at age 50 3.2 (1.9–5.5) 2.6 (1.5–4.3) 3.0 (2.0–4.3)
Weight 3.5 (2.1-5.7) 6.0 (2.9–12.2) 4.2 (2.8–6.4)
Fat mass 3.3 (2.0–5.6) 5.2 (2.5–10.7) 4.0 (2.6–6.0)
Waist circumference 3.6 (2.2–6.0) 5.1 (2.7–9.9) 4.2 (2.8–6.2)
Waist/hip ratio 1.9 (1.1–3.2) 3.1 (1.8–5.5) 2.4 (1.6–3.5)
Waist/height ratio 3.6 (2.2–5.9) 3.9 (2.2–7.1) 3.8 (2.6–5.5)

*Adjusted for age, race (African American vs non–African American), current smoking status, physical activity, diet score, and alcohol consumption

Participants who gained at least 9 kg from age 50 (that is, before baseline, based on self-reported weight) to the study's baseline had an adjusted hazard ratio (HR) for diabetes of 3.2 (95% CI 2.0–5.1) if their BMI was <25 at age 50, 4.0 (95% CI 2.5–6.4) if their BMI was 25 to 29 at age 50, and 5.0 (95% CI 2.5–10.0) if their BMI was at least 30 at age 50.

But among those who were at least 75 years of age, the risk of incident diabetes among those with the highest measures was attenuated by about one-half compared with younger participants.

Hazard Ratio* (95% CI) for Risk of Incident Diabetes, Highest Tertile of Adiposity Measures vs Lowest Tertile, by Age <75 Years vs >75 Years

Adiposity measure Age <75, n=2840 Age >75, n=1353
BMI 4.0 (2.8–5.7) 1.9 (1.0–3.6)
BMI at age 50 3.0 (2.2–4.2) 1.3 (0.7–2.3)
Weight 3.2 (2.3–4.5) 1.5 (0.9–2.7)
Fat mass 3.5 (2.4–4.9) 1.3 (0.7–2.5)
Waist circumference 3.5 (2.5–4.9) 1.6 (0.9–2.9)
Waist/hip ratio 2.3 (1.7–3.1) 1.3 (0.7–2.3)
Waist/height ratio 3.8 (2.7–5.4) 1.7 (1.0–3.1)

*Adjusted for age, race (African American vs non–African American), current smoking status, physical activity, diet score, and alcohol consumption

Biggs noted that the findings of increased diabetes risk even in middle-age and later contain an important public-health message, as older adults "have the highest risk of diabetes, they also have the highest and [fastest] growing rates of morbidity and mortality from cardiovascular disease. . . . And they're the fastest-growing segment of the population."

The study was primarily funded by the National Institutes of Health. The authors had no disclosures.


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