Meta-study: overweight people with a longer life expectancy than normal-weight people
Obese people live longer than people of normal weight, according to the surprising result of a meta-study published in the journal "The Medical American Association" (JAMA) by US and Canadian researchers. The researchers had evaluated the risk of mortality in relation to the different categories of the body mass index (BMI) in 97 previous studies and found that people with simple overweight (BMI between 25 and 30) had a lower mortality rate than normal people. The same applies, according to the researchers, to obesity in the first category (BMI 30 to 35), while the extreme forms in the second and third obesity categories (BMI 35 to 40; BMI greater than 40) were associated with a drastically increased mortality rate.
Scientists say that extremely obese people die much earlier than normal people, but this does not apply to people who are overweight and have moderate obesity. For example, researchers with the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (USA) and the University of write that people with a BMI between 25 and 30 actually have a six percent lower mortality risk than normal-weight people Ottawa (Canada). Even with obesity in the first category (BMI 30 to 35), the mortality risk is five percent lower than with normal weight people. On the other hand, the risk of mortality in extreme obesity (BMI over 35) increases by a full 29 percent, the scientists report in “JAMA”.
Relationship between body weight and mortality risk The researchers based their meta-analysis on the data from around 2.9 million patients from 97 previous studies. Accordingly, more than 270,000 deaths were considered in the current investigation. The almost three million subjects came mostly from North America, South America, Europe and Asia. The general assertion that obesity is associated with an increased risk of mortality can no longer be maintained given the data analysis that has now been published. However, the question arises as to why the overweight or slightly obese have a longer life expectancy than normal people. The researchers explain this on the one hand with the more frequent visits to the doctor. For example, those affected would be examined more often by a doctor, which means that potentially life-threatening diseases are discovered much earlier. On the other hand, the fat pads also served as energy reserves that benefit overweight and moderately obese people with certain diseases.
Obesity linked to numerous health risks According to the director of the CDC, Thomas Frieden, however, the current study results should not obscure how unhealthy obesity actually is. Even if the mortality risk for overweight and moderate obesity is lower than for normal weight, the increased body weight is associated with an increased risk of diabetes, cardiovascular problems (e.g. heart attack, high blood pressure, coronary heart disease) and cancer as well as several other health problems. For the approximately 30 percent of US citizens who are obese according to the CDC, there is still an increased health risk here - even if this does not necessarily have to be associated with increased mortality. (fp)
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