Waistlines in US continue to swell, medical study says

The average US citizen's waistline has expanded over the past decade, adding about 2.5 cm of belly fat from 1999 to 2012, researchers said Tuesday.

The findings in The Journal of the American Medical Association are the first to show how the nation's obesity epidemic has translated into added paunch in recent years, and the study said the trend toward larger waistlines was "significant".

More than one-third of US adults - 34.9 percent, or 78.6 million people - are considered obese, according to the US Centers for Disease Control and Prevention. The condition raises the risk of heart disease, stroke, cancer and diabetes.

Those figures are based on body mass index, a ratio calculated from weight and height. Recent research has shown no change in obesity rates according to BMI from 2003 to 2004, and from 2011 to 2012.

But when CDC researcher Earl Ford and colleagues examined data about waist circumference from the same national health registries, dating from 1999-2012, they found that there was a definite trend toward bigger bellies in the US.

"Our analyses using data from the same surveys indicate that the prevalence of abdominal obesity is still increasing," said the report.

"The reasons for increases in waist circumference in excess of what would be expected from changes in BMI remain speculative, but several factors, including sleep deprivation, endocrine disruptors, and certain medications, have been proposed as potential explanations."

For the purposes of the study, abdominal obesity was defined as a waist circumference greater than 102 cm in men and greater than 88 cm in women.

From a pool of nearly 33,000 men and nonpregnant women 20 or older, the overall age-adjusted average waist circumference increased "progressively and significantly", from 95.5 cm in 1999 and 2000 to 98.6 cm from 2011 and 2012, the study said.

Men gained on average 2 cm and women added 3.8 cm, it said.

"The overall age-adjusted prevalence of abdominal obesity increased significantly from 46.4 percent in 1999-2000 to 54.2 percent in 2011-2012," the study added.

Men and women saw "significant increases", with male abdominal obesity increasing from 37 to 44 percent, and women going from 55 to 65 percent.

(China Daily 09/18/2014 page11)