New research involving nearly 140,000 postmenopausal women reveals that measuring waist circumference alongside body mass index modestly improves the ability to predict mortality risk in older women.

The average waist size for U.S. women is 38.5 inches, indicating widespread abdominal obesity. Larger waist sizes are linked with increased risks of chronic diseases, like heart disease and diabetes.

While obesity remains a pressing public health threat, prevention and treatment are made difficult by the limits of the BMI to accurately measure excess adiposity, according to the study’s authors.