CDC: Waistlines still growing

Americans may have stopped putting on pounds, but their waistlines are still expanding, according to a new analysis from the Centers for Disease Control and Prevention.

The average waist circumference of U.S. adults has increased by about 3 percent since the end of the last century.

In 1999 and 2000, the waists of Americans who were at least 20 years old measured 37.6 inches around. By 2011 and 2012, that figure had grown to about 38.8 inches, CDC researchers report in today’s edition of the Journal of the American Medical Association.

Those figures are age-adjusted averages, but the trend applies to pretty much all demographic groups, the report says. Men and women both saw “significant increases” in waist circumference, as did “non-Hispanic whites, non-Hispanic blacks and Mexican Americans.” Waistlines of Asian Americans may have grown too, but the CDC didn’t start collecting data on them as a group until 2011.

Overall, the proportion of Americans suffering from abdominal obesity rose from 46.4 percent in 1999-2000 to 54.2 percent in 2011-2012, according to the study. (These figures were adjusted for age as well.)

The data on bigger waists come from the National Health and Nutrition Examination Survey, an ongoing study that combines physical examinations with in-depth interviews.

Interestingly, NHANES data were cited in February by another group of CDC researchers who declared that American obesity rates have experienced “no significant changes” between 2003-2004 and 2011-2012. That study, which was also published in JAMA, focused on body mass index.

“At a time when the prevalence of obesity may have reached a plateau, the waistlines of U.S. adults continue to expand,” the new report concludes.

While BMI is used to assess whether a person has enough excess body fat to be considered overweight or obese, the waist circumference measurement can help doctors predict whether that extra weight translates into serious health problems.

“If most of your fat is around your waist rather than at your hips, you’re at a higher risk for heart disease and Type 2 diabetes,” according to the National Heart, Lung and Blood Institute, part of the National Institutes of Health. Those risks kick in for women with a waist size above 35 inches and men with a waist size above 40 inches.