Health and Nutrition

January 11, 2006

Obesity Today Means Fatal Heart Disease Tomorrow

Filed under: General Health — Doc Joe @ 8:12 pm

By Neil Osterweil , MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.

Source News Article: ABC News, Forbes, Miami Herald, USA Today

CHICAGO, Jan. 10 – People who are obese in middle age are far more likely to be hospitalized and to die of diabetes and heart disease in old age, even if they are currently free of cardiovascular-disease risk factors.

Researchers here who kept tabs on more than 17,000 men and women — some for nearly 40 years — found that those who were obese in middle age had twice to quadruple the risk of being hospitalized for coronary heart disease in old age than their normal-weight peers, according to a report in the Jan. 11 issue of Journal of the American Medical Association.

“In this predominantly white cohort who survived to age 65 years and older, persons who were overweight, and particularly those who were obese earlier in life (ages 31-64 years), had significantly higher risks of hospitalization and mortality in older age compared with persons of normal weight with similar other cardiovascular risk factors at baseline,” wrote Lijing L. Yan, Ph.D., M.P.H., of Northwestern University here and colleagues in other centers.

Although obesity is associated with cardiovascular risk factors such as diabetes, hypertension, and high serum cholesterol, “controversies persist as to whether excess weight has an additional impact on cardiovascular disease outcomes beyond its effects on established risk factors,” the authors wrote. “Direct evidence on this issue is scant.”

To assess whether body weight in middle age is associated with morbidity and mortality later in life, the investigators looked at data on 17,643 men and women who took part in the Chicago Heart Association Detection Project in Industry study.

This prospective study enrolled people at baseline between 1967 and 1973 and stratified them by cardiovascular risk factors. The participants ranged in age from 31 to 64 years, and all were free of coronary heart disease, diabetes, and major electrocardiographic abnormalities at study entry.

Participants were classified as low risk if they had blood pressure that was <120/< 80 mm Hg, serum total cholesterol level of < 200 mg/dL, and were not currently smoking. Those at moderate risk were nonsmokers with systolic BP 121-139 mm Hg, diastolic BP 81-89 mm Hg, and/or total cholesterol level 200-239 mg/dL.

Participants were also considered to be at moderate risk for cardiovascular disease if they had one or more of the following risk factors: Blood pressure at > 140/90 mm Hg, a total cholesterol level at > 240 mg/dL, and current cigarette smoking.

Body mass index (BMI) was classified as normal weight (18.5-24.9), overweight (25.0-29.9), or obese > 30).

The main outcome measures were hospitalization and death from coronary heart disease, cardiovascular disease, or diabetes beginning at age 65. The mean duration of follow-up was 32 years.

The investigators conducted multivariable analyses that adjusted for systolic blood pressure and total cholesterol levels. They found that among obese participants, the odds ratio at the 95% confidence interval for coronary heart disease death compared with those of normal weight in the same risk category was 1.43 (0.33-6.25) for the low risk group and 2.07 (1.29-3.31) for the moderate-risk group.

Obese patients in the low risk category were more than four times more likely to be hospitalized for coronary heart disease than low-risk normal-weight patients (OR 4.25, 1.57-11.5). Moderate-risk obese people were twice as likely to be hospitalized for coronary heart disease (2.04, 1.29-3.24).

Results were similar for other risk groups and for cardiovascular disease, but stronger for diabetes,” the authors noted. For example, obese people in the low-risk group were 11 times more likely to have diabetes listed on their death certificates than low-risk normal-weight people (OR 11.0, 2.21-54.5). In addition, obese people in the low-risk category were nearly eight times more likely to be hospitalized for diabetes (7.84, 3.95-15.6).

“These outcomes are important to investigate in an era of population aging marked by an unprecedented large number of older adults resulting from aging of the baby boomers and from dramatic improvements in life expectancy for the entire population,” the investigators wrote.

Several limitations to the study were pointed out by the authors. “Our results should be interpreted with caution, as numbers for some of the 15 risk and BMI subgroups were small,” they wrote. “Another limitation is the lack of repeated risk-factor measurements over time. The influences of midlife BMI on older-age morbidity could be partially mediated through its effects on the eventual occurrence of hypertension, hypercholesterolemia, and diabetes later in life.”

They added, “Nonetheless, our results underscore the importance of including BMI earlier in life in comprehensive risk assessment.”

Primary source: Journal of the American Medical Association
Source reference: Yan LL et al. Midlife Body Mass Index and Hospitalization and Mortality in Older Age. JAMA. 2006;295:190-198.

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