According to new research, being slightly underweight is possibly associated with a higher risk of mortality than being overweight or obese, which increases the risk of death by anywhere between 22 percent and 91 percent — compared to the first. much more The findings, published February 9 in the journal Population Studies, counter prevailing wisdom that excess weight increases mortality only in extreme cases.
The statistical analysis of nearly 18,000 people also highlights the pitfalls of using body mass index (BMI) to study health outcomes, providing evidence that the go-to metric can potentially bias conclusions. With those biases in mind, it’s estimated that 1 in 6 American deaths is related to being overweight or obese.
“Existing studies underestimate the mortality consequences of living in a country where cheap, unhealthy food has become increasingly accessible and sedentary lifestyles have become the norm,” said study author Ryan Masters, associate professor of sociology at CU Boulder. ” “This study and others are beginning to uncover the true harm of this public health crisis.”
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Challenging the obesity paradox, while many studies show that heart disease, high blood pressure and diabetes (which are often associated with being overweight) increase the risk of mortality, very few have shown that higher BMI The mortality rate is higher in the groups.
Instead, in what some call the “obesity paradox,” most studies show a U-shaped curve: the “overweight” category (BMI 25–30) surprisingly has the lowest mortality rates. Those in the “obese” range (30-35) have little or no risk over the so-called “healthy” range (18.5-25). And both “underweight” (under 18.5) and extremely obese (35 and over) have an increased risk of death. There are actually some survival benefits to being overweight,” said Masters, a social demographer who has spent his career studying mortality.
“I am skeptical of these claims.” He noted that BMI, which doctors and scientists often use as a measurement of health, is based only on weight and height and does not take into account body composition or how long a person has lived. overweight. “It’s a reflection of stature at a time,” Masters said. category of “obese”.
“It’s not fully capturing all the nuances and the different sizes and shapes that bodies come in.” On data of 17,784 people including 4,468 deaths. They found that a full 20 percent of the sample described as “healthy” weight had been in the overweight or obese category in the prior decade. When isolated, this group had a significantly worse health profile than the same category of people whose weight was stable. Masters pointed out that carrying excess weight throughout life can lead to diseases, which paradoxically lead to rapid weight loss. If BMI data is captured during this time, it may skew the results of the study.
“I would argue that we are artificially increasing the risk of mortality in the low-BMI category by including people who have a high BMI and have recently lost weight,” he said. Meanwhile, 37 percent of those with an overweight and obese BMI of 60 percent had a lower BMI than in the prior decade. Notably, those who had recently gained weight had a better health profile.
“The health and mortality consequences of high BMI are not like a light switch,” Masters said. “An expanding body of work is suggesting that the results are duration-dependent.” By including people who have spent most of their lives in the higher BMI categories with lower BMI weights, previous studies inadvertently made higher BMIs less risky, he said. When they looked at differences in fat distribution within BMI categories, they also found that the variations made a huge difference in reported health outcomes.
Collectively highlighting a public health problem, the findings confirm that studies have been “significantly affected” by biases related to BMI. Crunching the numbers again without these biases, they found not a U-shape but a straight upward line, with the lowest mortality risk among those with a low BMI (18.5-22.5). In contrast to previous research, the study found no significant increase in mortality for the “underweight” category.
While previous research estimated that 2 to 3 percent of deaths among American adults were due to a high BMI, their study puts the toll at eight times higher. Masters said he hopes the research will alert scientists to be “extremely cautious” when drawing conclusions based on BMI. But he also hopes the work will draw attention to what he sees not as a problem for individuals alone to solve but as a public health crisis stemming from an unhealthy or “obese” environment in America. Let’s see in
“For cohorts born in the 1970s or 1980s who have lived their entire lives in this obesogenic environment, the prospects for healthy aging in old age just don’t look good,” he said. “I hope this work can influence high-level discussions about what we can do about it as a society.”