Health and Death Risks Underestimated for Extremely Obese Women

Health and Death Risks Underestimated for Extremely Obese Women

http://www.seniorjournal.com/NEWS/He...thAndDeath.htm


July 5, 2006 - The health risks for women who are extremely obese may
be underestimated as a new study indicates they have a higher
prevalence of hypertension, diabetes, and high cholesterol than women
at lower levels of obesity, which increases the risk of death.
Interestingly, however, they found obesity creating less risk among
older white women, according to a study in the July 5 issue of JAMA.

Obesity diagnosis and treatment are typically based on body mass index
(BMI) of at least 30. BMI is calculated as weight in kilograms divided
by height in meters squared.

However, three categories of obesity are defined: obesity 1 (30-34.9);
obesity 2 (35-39.9); and extreme obesity (40 and greater). (A 5'4"
person would have a BMI of 40 if they weighed 233 lbs).

The latter 2 categories, sometimes termed severe obesity, are reported
to be increasing especially rapidly in the United States, according to
background information in the article. From 1986 to 2000, prevalence of
BMI of 30 or higher approximately doubled, while that of BMI of 40 or
higher quadrupled and that of BMI of 50 or higher increased 5-fold. In
2000, 2.8 percent of all U.S. women, and 6 percent of black women
reported measurements consistent with extreme obesity.

Estimates of obesity-related risks in women have generally been based
on weight data that preceded the increase in extreme obesity. It has
been unclear whether health risk increases or plateaus as body weight
increases throughout the obese range.

Kathleen McTigue, M.D., M.S., M.P.H., of the University of Pittsburgh,
and colleagues conducted a study to examine the relationship between
weight category and risk of death and coronary heart disease (CHD) in a
large population-based sample of U.S. women, focusing on risk across
degree of obesity.

The researchers analyzed data on incident death and cardiovascular
outcomes by weight status in 90,185 women recruited from 40 U.S.
centers for the Women's Health Initiative-Observational Study who
were followed-up for an average of 7.0 years (Oct. 1993 to Aug. 2004).

The researchers found that extreme obesity prevalence differed with
race/ethnicity, from 1 percent among Asian and Pacific Islanders to 10
percent among black women.

"In this diverse population-based sample of older women, we found
that obesity was linked with considerable health risk and that
accounting for degree of excess weight is important in understanding
weight-related health risk. Overall, extremely obese women were more
likely to die over the average 7.0 years of follow-up than were women
in other examined weight categories. Modeling analyses adjusted for
age, smoking status, educational achievement, U.S. region, and physical
activity level showed that weight-related risk for all-cause mortality,
CHD mortality, and CHD incidence did not differ by race/ethnicity.

"There was a positive trend in all-cause mortality risk and CHD
incidence with increasing weight category. This trend had borderline
significance for CHD mortality among black women, likely reflecting
sample size limitations. Much of the obesity-related mortality and CHD
risk was mediated by diabetes, hypertension, and hyperlipidemia [high
cholesterol levels].

"In white women, as other studies have found, weight-related all-cause
mortality risk was modified by age, with obesity conferring less risk
among older women. (At each decade of baseline age, rates of all-cause
mortality were higher in the obese vs normal BMI weight categories.
However, the relative increase in mortality rates with weight category
decreased with age.)

"Smoking may modify weight-related risk in black women, but further
study is needed to understand the nature of this relationship," the
authors write.

"Our findings have important clinical and policy implications. The
escalating prevalence of extreme obesity may exacerbate the health
effects and health-related expenditures resulting from the U.S. obesity
epidemic. Calculating the weight-related risks of morbidity and
mortality based on findings in earlier population samples, which tended
to reflect lower degrees of obesity, may underestimate the risks for
extremely obese individuals and overestimate the risks for mildly obese
individuals in diverse groups," the researchers write.

"More accurately assessing weight-related health risk may both
improve policy decisions about obesity and assist women in making
informed decisions about their health."

Editor's Note: The Women's Health Initiative program is funded by the
National Heart, Lung, and Blood Institute, U.S. Department of Health
and Human Services. Dr. McTigue was supported by a grant from the
National Institute of Diabetes and Digestive and Kidney Diseases.

http://www.seniorjournal.com/NEWS/He...thAndDeath.htm