Maintaining normal waist circumference can help prevent COPD

Individuals with a large waist circumference may face a higher risk of developing chronic obstructive pulmonary disease (COPD), according to a study published July 7 in CMAJ (Canadian Medical Association Journal).

Lead researcher Gundula Behrens, PhD, department of Epidemiology and Preventive Medicine, University of Regensburg, Germany, and colleagues studied the relationship between obesity and physical activity to the incidence of COPD among more than 100,000 middle-aged to elderly men and women living in the United States.

The researchers collected data on waist circumference and level of physical activity from 113,279 participants of the National Institutes of Health–AARP Diet and Health Study who did not have COPD, cancer or heart disease at the beginning of the study (1995 to 1996).

They estimated associations between waist circumference, physical activity, and subsequent diagnosis of COPD between 1996 and 2006, with extensive adjustment for smoking and other potential risk factors for COPD.

People with a large waist circumference (43.5 inches (110 cm) or over in women and 46.5 inches (118 cm) or over in men) had a 72% increased risk of COPD as compared to people with a normal waist circumference. In contrast, individuals who were physically active five times or more per week had a 29% decreased risk of COPD as compared to their physically inactive counterparts.

“Established primary means of COPD prevention include avoidance of exposure to tobacco smoke, air pollution, and occupational dust damaging the lungs,” Behrens said. “Our study suggests that COPD may be additionally prevented by maintaining a normal waist circumference and following recommended levels of physical activity. Physicians should encourage their patients to follow the waist circumference and physical activity guidelines.”

According to the World Health Organization (WHO), women should keep their waist circumference below 35 inches (88 cm) and men below 40 inches (102 cm). Men and women should engage in 30 to 60 minutes of moderate-intensity physical activity at least 5 times per week or 20 to 60 minutes of vigorous-intensity exercise at least three days per week, as suggested by the American College of Sports Medicine.

“Maintaining a normal waist circumference and recommended levels of physical activity may decrease the risk of COPD,” Behrens said.

While excessive visceral fat and lack of physical activity have previously been linked to accelerated progression of COPD among patients with established disease, their relations to the first occurrence of COPD had remained unclear, according Behrens.

“No previous study had examined the relationship between abdominal adiposity and COPD incidence, and previous data on physical activity and COPD were limited,” Behrens said. “Our prospective study is the first to investigate waist circumference in relation to COPD and the largest to explore the association between physical activity and COPD.”