Study Finds High BMI Alone May Not Be Linked to Early Death
For decades, medical professionals have relied on body mass index (BMI) to measure a patient's propensity for disease and other weight-related health problems. The scale's credibility as a sole indicator of health has been called into question in recent years, and a new study reaffirms the belief that a high BMI alone might not be linked to early mortality after all.
The study published on July 5 declared that high BMI alone can't be considered a direct cause of mortality, and that it must be considered in tandem with other risk factors in adults. The report also concluded that more studies incorporating weight history, body composition, and morbidity outcomes need to be conducted to properly paint a full picture.
“The real message of this study is that overweight as defined by BMI is a poor indicator of mortality risk, and that BMI in general is a poor indicator of health risk and should be supplemented with information such as waist circumference, other measures of adiposity (fat), and weight trajectory,” study author Dr. Aayush Visaria, an internal medicine resident physician at the Rutgers Robert Wood Johnson Medical School, said of the findings, per CNN.
The results showed there was no significant increase in risk of death for subjects 65 years and older with BMIs between 22.5 and 34.9 independent of other risk factors. The same held true for younger adults with BMIs between 22.5 and 27.4. A BMI between 25 and 29.9 is considered overweight while 30 and above is considered obese.
Related: New BMI replacement is here: BVI
Visaria's caveat that other measures like waist circumference can help give insight into a person's health in relation to their weight aligns with a new policy adopted by the American Medical Association last month. The organization has begun advising physicians to use other metrics including waist circumference, fat distribution in the body, and genetic factors to assess a patient's health. Case in point: the study compared people with equal BMIs but different waist circumferences and found that bigger waists were associated with a higher risk of death overall.
The study does have some limitations, notably that it focuses on death as the negative outcome but doesn't examine the development of comorbidities like diabetes or heart disease that could lower quality of life or become future risk factors for premature death. It also did find a higher risk of death for adults under 65 with BMIs over 27.5, with rates rising significantly on the higher end of the scale as people developed significant levels of obesity.
The research upholds recent conclusions about BMI and adds to the chorus of voices pointing out the ineffectiveness of predicting health outcomes based on the outdated metric. "Our results are basically confirming a lot of other studies that have been done in recent years—not at this large of a level, but basically confirming that BMI by itself is really a poor indicator of health risk," Visaria told NBC News. Still, it's another brick in the foundation of the anti-BMI argument and a step toward making comprehensive health evaluations the norm.
