Adults who carry most of their excess weight
around the middle may be at particular risk
of high blood pressure, new research shows.
In a 10-year study
of Chinese adults, researchers found that
those whose waistlines expanded over the years
showed a similar increase in blood pressure.
Moreover, even young men and women who were
abdominally obese at the start of the study,
or who became so over time, were more likely
to be diagnosed with high blood pressure.
The findings appear in the American Journal
of Hypertension.
Research has shown that "apple-shaped" people
are at greater risk of heart disease and type
2 diabetes than those whose extra pounds dwell
largely on the hips and thighs. Studies have
also suggested that general obesity raises
the risk of high blood pressure, or hypertension.
But it hasn't been clear whether abdominal
obesity, per se, can cause hypertension, Dr.
Chen-Huan Chen, the study's senior author
stated.
This study may be the first to "clearly show"
that abdominal obesity predicts future hypertension,
regardless of a person's current blood pressure
or overall body weight, said Chen, a professor
of medicine at National Yang-Ming University
in Taipei, Taiwan.
It is possible, he noted, for a person to
have a very large waistline but not weigh
enough to be considered generally obese.
For their study, Chen and his colleagues
followed 2,377 men and women age 30 and up
for 10 years, during which time one-quarter
developed high blood pressure. Those with
large waistlines at the outset had a higher
risk than their slimmer counterparts, as did
people who became abdominally obese during
the study period.
Even in a group of healthy adults ages 30
to 43 years, the researchers found that those
whose waistlines expanded also saw their blood
pressure increase.
Abdominal obesity often exists as part of
a cluster of conditions known collectively
as metabolic syndrome -- the other components
being abnormal cholesterol levels, hypertension
and insulin resistance, a precursor to type
2 diabetes.
It's a complex collection of heart risks,
and it's not fully clear which problem might
cause the others. But the current findings
support the theory that abdominal obesity
is the "true culprit" that spurs the development
of insulin resistance, and then other components
of metabolic syndrome, according to Chen.
If that's the case, he noted, "it is obvious
that the most important thing to do is to
prevent abdominal obesity, not just obesity."
There's no single definition of abdominal
obesity, but in general, the waist sizes used
to define metabolic syndrome are 35 inches
or more for women and 40 inches or more for
men.
SOURCE: American Journal of Hypertension,
August 2006.
