Overweight live longer, according to Metastudie

Meta-study: Overweight with higher life expectancy than normal weight

01/02/2013

Overweight people live longer than people with normal weight, so the surprising result of a specialist magazine „Journal of the Medical American Association“(JAMA) published meta-study by US and Canadian researchers. The scientists had evaluated the mortality risk related to the different categories of body mass index (BMI) in 97 previous studies and found that people with a simple overweight (BMI between 25 and 30) had a lower mortality, than normal weight. According to the researchers, the same applies to obesity (obesity) of the first category (BMI 30 to 35), while the extreme forms of the second and third categories of obesity (BMI 35 to 40, BMI greater than 40) were associated with a drastically increased mortality.

Although extremely obese people, according to the scientists die much earlier than normal weight, but this does not apply to people with overweight and moderate obesity. Indeed, individuals with a BMI between 25 and 30 actually have a 6 percent lower mortality risk than normal weight, write the researchers of the US Health Authority „Centers for Disease Control and Prevention“ (CDC), the National Cancer Institute (USA) and the University of Ottawa (Canada). Even with obesity of the first category (BMI 30 to 35), the mortality risk is five percent lower than normal weight. On the other hand, the mortality risk for extreme obesity (BMI above 35) increases by as much as 29 percent, the scientists report „JAMA“.

Correlation between body weight and mortality risk
The researchers based their meta-analysis on data from approximately 2.9 million patients from 97 previous studies. More than 270,000 deaths were therefore included in the current investigation. The nearly three million subjects came for the most part from North America, South America, Europe and Asia. The general claim that obesity is associated with an increased mortality risk can no longer be maintained given the now published data analysis. However, the question arises why the overweight or slightly obese have a longer life expectancy than normal weight. 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 physicians, thus identifying potentially life-threatening illnesses much earlier. On the other hand, the fat pads also served as energy reserves that benefit the overweight and moderately obese people in certain diseases.

Overweight associated with numerous health risks
However, according to CDC head Thomas Frieden, the current study results should not obscure how unhealthy obesity actually is. Although the mortality risk for overweight and moderate obesity is lower than normal weight, the increased body weight is associated with an increased risk of diabetes, cardiovascular problems (eg, 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 go hand in hand with increased mortality. (Fp)

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Picture: neroli