NEW ORLEANS — JAMA (Journal of the American Medical Association) Network Open reported in July 2019 that, “normal-weight central obesity in women was associated with excess risk of mortality, similar to that of women with BMI-defined obesity with central obesity.”
The research study - the Association of Normal-Weight Central Obesity with All-Cause and Cause-Specific Mortality Among Postmenopausal Women – sought to determine how central (abdominal) obesity might be associated with mortality risk, based on other body phenotypes types.
These findings, notes JAMA, “underscore the need for future public health guidelines to include the prevention and control of central obesity, even in individuals with normal BMI.”
BMI (body mass index) – your weight in kilograms divided by your height in meters squared – “is the standard measure used to define obesity in clinical and public health guidelines.” However, BMI has an inherent limitation in that it does not distinguish body shape or body fat distribution.
Researchers from University of Iowa, Albert Einstein College of Medicine, Bronx, New York, Kaiser Permanente, Northern California, Fred Hutchinson Cancer research Center, Seattle, Washington, University of California, San Diego, and numerous other institutions state that central obesity – visceral abdominal obesity – has been associated with a higher risk of death irrespective of BMI status.
The ranges for BMI include normal weight at 18.5 to 24.9, overweight at 25 to 29.9, obese 30 or greater, while central obesity in females was defined as having a waist circumference (WC) equal to or greater than 88 centimeters (35 inches).
The study – using the Women’s Health Initiative (WHI) population from 40 clinical center in a randomized clinical trial or an observational study - recruited postmenopausal women (156,624) aged 50 to 79 from 1993 to 1998.
At baseline, height, weight, WC, BMI, age, race/ethnicity, educational and activity level, smoking status, alcohol intake, total energy intake, overall diet quality, and past hormone usage, were assessed.
Mortality status was obtained from death certificates, medical records, and the National Death Index for all-cause mortality, cardiovascular disease, and cancer.
Normal-weight, central obesity was, “associated with a higher risk of all-cause, cardiovascular disease, and cancer mortality compared with normal-weight without central obesity,” which caused the researches to comment that, “normal-, central obesity is an underrecognized, high-risk phenotype for mortality.
It was concluded that, “our results highlight the inability of BMI alone to distinguish body shape or body fat distribution, the misclassification of risk because of adiposity that occurs when using BMI as a proxy for fat mass, and the importance of measuring central obesity even among people with normal weight.”
Furthermore, “our results demonstrated that WC can be used in combination with BMI to better stratify patients for mortality risk.”