
WASHINGTON, Jan. 10 (UPI) -- People who are obese at middle age increase their risk of mortality and hospitalization in old age, compared to those of normal weight, a 38-year study shows.
"What is amazing, even after we have seen other studies showing similar findings, is the fact that one-time measurements over 30 years can be so predictive," said the study's lead author, Dr. Lijing L. Yan of Northwestern University and China's Peking University.
The study, in the new Journal of the American Medical Association, tested the body mass index of 17,643 men and women of varying weights between 1967 and 1973. Body mass indexes, or BMIs, measure a person's body fat based on height and weight.
The participants were divided into four categories of low to high risk, based on risk factors such as blood pressure and cigarette smoking. When the participants reached 65, researchers began to track their rates of hospitalization and mortality due to cardiovascular disease, coronary heart disease and diabetes.
The results showed the level of mortality and hospitalization spiked for overweight or obese participants, regardless of what risk category they were in.
There is no question obesity causes high blood pressure, high cholesterol and earlier onset of diseases such as type-2 diabetes. However, obesity research rarely focuses on midlife BMI and its relationship to health in later years. Yan's study adds to limited research indicating that overweight or obese people may suffer from additional health problems beyond already known risk factors.
In the study, obese participants at low risk for problems such as high blood pressure and high cholesterol were just as likely to die prematurely or become hospitalized as their obese counterparts with high risk. For example, the possibility of death from coronary heart disease increased by 43 percent in an obese group considered to have low risk factors, compared to those of a normal weight.
"This is what we thought all along," said Robert Eckel, president of the American Heart Association and professor at the University of Colorado at Denver and Health Sciences Center. Eckel wrote about obesity's deadly toll in a 1998 AHA "Call to Action" paper. "That's the message of this study -- when three major risks are taken into consideration, obesity adds to the risk. Being obese is not in your best interest."
However, Eckel warns the study has limitations, particularly since researchers tested the participants' BMI only once, in the 1960s or 1970s. The more than 30-year gap could allow for drastic changes in a participant's health, for instance. In addition, 87 percent of the participants were Caucasian, so it's unknown if the same results would apply to minorities.
Nonetheless, more studies are not needed to prove obesity's rampant growth in the United States, Eckel said. About 60 million U.S. adults are obese, according to the American Obesity Association.
The rate of overweight and obese people has skyrocketed in recent decades: the percentage of obese men in the United States doubled between 1988 and 1999, jumping from 14.1 to 25.8 percent.
The study should be a wake-up call to turn the country's attention to prevention and treatment, Eckel says. Eckel suggests that adults monitor their weight as they do potential diseases, such as cancer, and work to continually keep weight gain in check.
As the study concludes, strong support for wide, multi-faceted prevention of obesity, starting with children, is key in adding to existing progress in stopping cardiovascular disease and coronary heart disease. Yan pointed to the success of anti-smoking campaigns and national blood pressure and cholesterol reduction efforts as models for reversing the obesity epidemic.
"Our study is not in a vacuum," Yan said. "It is one more piece of evidence that people should pay more attention to their weight, even if they have their risk factors under control."
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E-mail: consumerhealth@upi.com
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