According to a new study, there is not necessarily a correlation between having a high body mass index (BMI) and an increased mortality risk. This research adds to the growing body of data showing that BMI alone is not a reliable predictor of health outcomes.
Study determined impact of high BMI
- The journal PLOS One study examined data from upwards of 550,000 adults in the U.S. to determine the association between body mass index (BMI) and mortality from any cause.
- Those with a BMI between 22.5 and 34.9 did not have a significantly higher risk of dying than those with lower BMIs.
- This also held true for younger adults – those with BMIs between 22.5 and 27.
Generally, if your BMI is 25 or more, you are considered overweight; if it’s 30 or more, you are obese.
To determine BMI, you simply divide the weight of an individual by the square of their height. For decades, this has been the standard method for determining whether or not a person’s weight presents a danger of developing diabetes or cardiovascular disease. However, many medical experts have argued that BMI ignores important details like a person’s body fat percentage and the fact that the risk of disease varies greatly between ethnic groups and sexes.
The American Medical Association has passed a resolution urging doctors to consider more characteristics when determining a patient’s health, such as waist size, fat distribution, and genetics and not only a high BMI.
Dr. Aayush Visaria, a resident in internal medicine at Rutgers Robert Wood Johnson Medical School and a co-writer of the new study, says the results back up the revised guidelines.
“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 remarked.
He also mentioned that waist circumference may be a more reliable indicator, as the study matched people with the same body mass index but varying waist circumferences and showed that the latter was related to a greater likelihood of death.
However, those with a BMI of 30 or higher had a significantly higher chance of dying. BMIs between 27.5 and 29.9 were also related, with approximately 20% increased risk among younger adults.
Previous studies have uncovered flaws in using BMI to determine obesity and weight-related illness risk. Almost 50% of the participants in a 2016 research who were classified as overweight – and 29% who were classified as obese – were found to be healthy from a metabolic perspective. On the flip side, more than 30% of those with weights taken as ‘normal’ were actually metabolically unhealthy.
Dr. Fatima Stanford, an obesity medicine expert at Massachusetts General Hospital, emphasized that the BMI thresholds spanning overweight and obesity fail to take into consideration racial and cultural disparities. For instance, some studies have shown that Asians may be at greater risk than the overall population for acquiring metabolic disorders like diabetes and hypertension, while having a BMI that is below the general level.
