March 6, 2009 -- Inflating that "spare tire" around your waist may put the
squeeze on your lungs, a new French study shows.
Scientists have long suspected abdominal obesity to pose its own health risks, aside from those
of being overweight. Abdominal obesity is a component of metabolic syndrome, which also includes a low level of
HDL "good" cholesterol, an elevated level of triglycerides (blood fats), elevated blood pressure,
and elevated blood sugar. People with at least three of the components are
considered to have metabolic syndrome. Having metabolic syndrome increases
one's risk of developing heart
disease, stroke, and diabetes.
The current study shows that metabolic syndrome is also associated with
impaired lung function. Further, abdominal obesity -- compared to the other
factors -- is most tightly linked to the lung function impairment.
Researchers in France recruited more than 120,000 people. They performed a
physical exam with blood tests, and checked demographic information, smoking status, measured their waistlines, and tested
their lung function.
Those with metabolic syndrome were about 1.4 times more likely to have lung
function impairment. But researchers were surprised by the findings in people
with abdominal obesity.
People with excess belly fat were twice as likely to have impaired lung
function. This was true even if their weight was normal. Previously, experts believed only
severe obesity contributed to decreases in lung function.
Researchers aren't sure what the relationship is between big bellies and bad
breathing. The effect could be mechanical: a large belly might restrict the
diaphragm and make it harder for lungs to expand. Or, the extra fat could
increase inflammation in the body, somehow harming the lungs.
Abdominal obesity is defined most often as a waistline greater than 35
inches for women, and 40 inches for men. More than half of American adults
today have bellies this size or larger. The average French man in the study had
a 35-inch waist, at an average age 46. The average French woman's waist was
about 30 inches at the same average age.
The study appears in the American Journal of Respiratory and Critical