A large, long-term follow-up study revealed that obesity at middle age can lead to heart disease even when obvious risk factors, such as high blood pressure (BP) and high cholesterol, are absent. The study, out of Chicago's Northwestern University, included 17,643 people whose body mass index (BMI) and cardiovascular risk factors were assessed at midlifeconsidered to be between the ages of 31 and 64between 1967 and 1973. They were followed through 2002, and their rates of hospitalization and death from coronary heart disease (CHD), cardiovascular disease, and diabetes were assessed. The study group was subdivided into 5 groups: nonsmokers with normal BP whose cholesterol was <200 mg/dL without the aid of medication (low risk); nonsmokers not on medication but with slightly elevated BP and cholesterol (moderate risk); and those with 1, 2, or 3 risk factors of high BP, high cholesterol, and active smoking (intermediate, elevated, and highest risk). Study groups were further divided by their BMInormal, overweight, or obese. Moderate-risk, obese patients had twice the risk of CHD death and hospitalization after age 65, compared with their normal- weight counterparts. Among the low risk group, obesity increased the CHD death and hospitalization rates by 1.43- fold and 4.25-fold, respectively. Both groups had a 7-fold increase in diabetes risk if patients were obese. In the intermediate-, elevated-, and highest-risk groups, being overweight was associated with poor health but not to the magnitude that obesity supports. Lead author Lijing L. Yan, PhD, MPH, said that she was surprised at how "just one BMI measurement in midlife could so strongly predict outcomes in older age."
Ms. Farley is a freelance medical writer based in Wakefield, RI.