Health
Effects of Overweight/Obesity
The health risks
associated with obesity are summarized in the Surgeon
General's Call To Action To Prevent and Decrease Overweight and Obesity
(html
for health risks section).
Obesity is a major
risk for several of the key health problems on this website,
diabetes
hypertension
high cholesterol
osteoarthritis
asthma
as well as many
others, including several types of cancer, gall bladder disease,
and disability. Health care would be much less expensive and more
effective if we were all slimmer.
Body
Mass Index and Mortality
In
a 14-year prospective study of more than one million adults in the United
States, death from all causes increased with body mass indexes (BMI)
greater than 23.5 to 24.9 for men or 22.0 to 23.4 in women. The greatest
effects were seen among nonsmokers without a history of disease. Those
with the highest BMIs had a roughly two-fold increase in risk of premature
mortality. The effects were greater among whites than blacks and were
greater among men than women. Nevertheless, a risk associated with increasing
BMI was apparent for all groups [Calle et al, N Engl J Med 1999, PubMed].
This study confimed previous findings that excess body weight increases
the risk of death from any cause and from cardiovascular disease regardless
of age [Stevens et al, N Engl J Med 1998, PubMed].
In
a more recent prospective study of 900,000 U.S. adults [Calle et al,
N Engl J Med 2003, PubMed],
increased body weight (assessed as BMI) was associated with an increased
risk of cancer. The heaviest (those with BMI of 40 or more) had death
rates from all cancers combined that were more than 50 percent higher
than those of normal weight. Based on the current patterns of overweight
and obestiy in the United States, the authors estimated that 14% of
all cancer deaths in men and 20% of all cancer deaths in women could
be attributed to overweight and obesity.
Data
from the Nurses Health Study [Hu et al, N Engl J Med 2004, PubMed]
suggest that excess body weight (BMI higher than 25) and physical inactivity
are independent risks for premature mortality.
More
recently, Flegal et al [JAMA 2005, PubMed]
published evidence suggesting that overweight (BMI 25 to 29.9) may not
be a risk for premature mortality, but these unexpected results may
have been due to the effects of Rx treatment for high cholesterol or
high blood pressure, which is more common among heavier patients. (This
study controlled for smoking but not for Rx drug use.) This explanation
was noted by the authors, and supported up by an accompanying article
in the same issue [Gregg et al, JAMA 2005, PubMed].
