WASHINGTON, Aug. 10 (Xinhua) -- Individuals with a large waist circumference appear to have a greater risk of dying from any cause over a nine-year period, according to a report in the August 9/23 issue of U.S. journal Archives of Internal Medicine.
Having a large waist circumference has previously been associated with inflammation, insulin resistance, type 2 diabetes, abnormal cholesterol levels and heart disease, according to background information in the article. This may be because waist circumference is strongly correlated with fat tissue in the viscera -- surrounding the organs in the abdomen -- which is thought to be more dangerous than fat tissue under the skin.
Researchers at the American Cancer Society examined the association between waist circumference and risk of death among 48, 500 men and 56,343 women aged 50 and older (median or midpoint age, 69 years in men and 67 years in women). All had participated in the Cancer Prevention Study II Nutrition Cohort, for which they completed a mailed questionnaire about demographic, medical and behavioral factors in 1992 or 1993 and provided information about weight and waist circumference in 1997.
Deaths and their causes were tracked through the National Death Index until Dec. 31, 2006, while a total of 9,315 men and 5,332 women died during this timeframe.
After adjusting for body mass index (BMI) and other risk factors, very large waists (120 centimeters or 47 inches or larger in men, and 110 centimeters or 42 inches or larger in women) were associated with approximately twice the risk of death during the study period.
A larger waist was associated with higher risk of death across all categories of BMI, including normal weight, overweight and obese. However, among women, the association was strongest for those at a normal weight.
"The reason for the stronger association between waist circumference and mortality among women with low BMI in our study is unclear," the authors write. "Future detailed analyses of the relationship between waist circumference and visceral adipose tissue or measures of insulin resistance within categories of BMI could identify biological reasons for potential differences in the strength of the association between waist circumference and mortality."