US Waistlines Continue to Increase

The prevalence of abdominal obesity and average waist circumference increased among US adults from 1999 to 2012, according to a study in The Journal of the American Medical Association.

Waist circumference is a simple measure of total andintra-abdominal body fat. Although the prevalence of abdominal obesity has increased in the United States through 2008, its trend in recent years hasn't been known, according to background information in the article.

Earl S. Ford, MD, MPH, of the Centers for Disease Control and Prevention in Atlanta, and colleagues used data from seven two-year cycles of the National Health and Nutrition Examination Survey (NHANES) starting with 1999-2000 and concluding with 2011-2012 to determine trends in average waist circumference and prevalence of abdominal obesity among adults in the United States. Abdominal obesity was defined as a waist circumference greater than40.2 inches (102 cm) in men and greater than 34.6 inches (88 cm) in women.

Data from 32,816 men and nonpregnant women aged 20 or older were analyzed. The overall age-adjusted average waist circumference increased progressively and significantly, from 37.6 inches in 1999-2000 to38.8 inches in 2011-2012. Significant increases occurred in men (0.8 inch),women (1.5 inches), non-Hispanic whites (1.2 inches), non­Hispanic blacks (1.6 inches), and Mexican Americans (1.8 inches).

The overall age-adjusted prevalence of abdominal obesity increased significantly from 46.4% in 1999-2000 to 54.2% in 2011-2012. Significant increases were present in men (37.1% to 43.5%), women (55.4% to64.7%), non-Hispanic whites (45.8% to 53.8%), non-Hispanic blacks (52.4% to60.9%), and Mexican Americans (48.1% to 57.4%).

The authors wrote that previous data analyses from NHANES show that the prevalence of obesity calculated from BMI didn't changesignificantly from 2003-2004 to 2011-2012. "In contrast, our analyses using data from the same surveys indicate that the prevalence of abdominal obesity is still increasing. 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.

"Our results support the routine measurement of waist circumference in clinical care consistent with current recommendations as a key step in initiating the prevention, control, and management of obesity amongpatients."

Source: The Journal of the American Medical Association