Feb 28, 2023 07:00:00

``Obesity paradox'' is the end, or research results contrary to common sense that it is OK even if it is slightly overweight are reported

While obesity is known to be the cause of various diseases, mortality statistics show that overweight people tend to live longer, a phenomenon known as the '

obesity paradox .' I'm here. But a new study analyzing weight trends over nearly three decades shows that overweight and obesity are more dangerous than previously thought.

Sources and severity of bias in estimates of the BMI–mortality association: Population Studies: Vol 0, No 0
https://doi.org/10.1080/00324728.2023.2168035

Excess weight, obesity more deadly than previously believed | CU Boulder Today | University of Colorado Boulder
https://www.colorado.edu/today/2023/02/23/excess-weight-obesity-more-deadly-previously-believed

Many studies comparing the body mass index (BMI) obtained from height and weight and the risk of death have found that the risk of death in people with BMI values of ``low weight (less than 18.5)'' and ``extreme obesity (35 or more)'' While it is high, the risk of death for those who are overweight (25 or more and less than 30) is surprisingly low, and the risk of death for those who are 'obese (30 or more and less than 35)' is also lower than that for those who are 'healthy (18.5 or more and less than 25).' It has been shown that the

If you graph this, it will be a U-shaped curve, so it was traditionally said that ``the risk of death does not increase unless the BMI is extremely high, and being overweight has advantages in favor of survival.'' .

by James Heilman, M.D.

Ryan K. Masters, an associate professor of sociology at the University of Colorado at Boulder, is skeptical of this view. Mr. Masters said, 'Tom Cruise is 5 feet 7 inches (about 170 cm) tall, but at one time he weighed 201 pounds (about 91 kg) and was muscular, but when converted to BMI, it was treated as 'obesity' with 31.5. In addition to introducing the famous case of 'I'm overweight', BMI, which is often used by doctors as an indicator of health, only looks at weight and height at a certain point in time, and does not take into account

body composition and periods of overweight. pointed out.

To examine the impact this 'BMI pitfall' has had on previous research, Masters used data from the National Health and Nutrition Examination Survey (NHANES) from 1988 to 2015, We analyzed data from 17,784 individuals, including 4468 deaths.

As a result, a whopping 20% of 'healthy' weight people were in the 'overweight' or 'obese' group 10 years ago, compared to those whose weight had remained stable over time. It turned out that my health was quite bad. On the other hand, 37% of those whose BMI was 'overweight' and 60% of those whose BMI was 'obese' had lower BMI 10 years ago, and those who had recently gained weight were in good health.

Based on this result, by classifying cases in which people who were overweight in previous studies fell ill and lost a lot of weight as ``underweight,'' the health condition of thin people appeared to be poor, and conversely, Masters said that recently overweight people may have been categorized as 'overweight' and the health risks of obesity may have been underestimated.

In addition, this study also found that even if BMI was the same, health conditions differed greatly depending on how fat was distributed. When Mr. Masters recalculates without these BMI-related biases, the graph of mortality risk and BMI draws a straight upward line instead of a U-shape, and people with a BMI of 18.5 or more and less than 22.5 have the highest mortality risk. was found to be low. Also, unlike the results of previous studies, we did not find a phenomenon in which 'underweight' significantly increased the risk of death.

'The effects of high BMI on health and mortality risk aren't as obvious as flipping a switch,' Masters said. 'A growing body of research suggests these effects depend on how long you've been overweight. I will.”