Years of Life lost Due to Obesity
Summary written by Kevin Fontaine, Ph.D.
It is well known that obesity promotes health problems and takes a toll on quality of life. As such, public health officials and organizations have disseminated health messages regarding the dangers of obesity, but they have not produced the desired effect. To address this, Fontaine and colleagues used population-based data to estimate the expected number of years of life lost (YLL) due to overweight and obesity across the life span of an adult (Journal of the American Medical Association 2003; 289:187-193).
Methods: Using data from the Third National Health and Nutrition Examination Survey (NHANES III), the NHANES I and II epidemiologic follow up study, the NHANES II Mortality Study and the 1999 U.S. Life Expectancy Tables, they calculated the difference between the numbers of years of life expected if an individual were obese versus not obese at a given age.
Results: The results were dramatic. They estimated that a 20-year-old white male with a body mass index (BMI) of 45 or more, the equivalent of a person who is 54″ and weighs over 260 lbs., is estimated to die 13 years sooner than a 20-year-old male who is not obese. A 20-year-old white woman with a BMI of 45 is estimated to lose 8 years. It was estimated that 2 to 5 years of life would be lost at more moderate levels of obesity (BMIs greater than 30: equivalent to a person who is 54 and weighs at least 174 lbs.). Results for African-Americans were somewhat different in that consistent reductions in life expectancy were not observed until BMIs were in the upper 30s. However, among African-Americans at younger ages with BMI of 45 or more, 20 years of live were estimated to be lost for men and 5 for women.
Conclusions: Obesity appears to significantly lessen life expectancy.
Editorial Comments: These results confirm what has been known for a long time: being obese is unhealthy. At a time when nearly 34 percent of the American population is obese and physicians are struggling to address the problem, information on the years of life lost due to obesity has the potential to impact patients health habits by presenting the very effects of being overweight in a way that patients can easily understand. However, it is important to note that estimates are just that approximations of the effects of obesity. The results do not account for other factors that influence life expectancy such as pre-existing disease, genetic factors, and socioeconomic characteristics. Thus, these estimates should be viewed a broad guidelines of the effect of obesity on life span. Nonetheless, they might be useful to physicians who often counsel their patients on the dangers of obesity. That is, these estimates that might motivate persons who struggle with their weight to make a concerted effort to lose weight and to maintain a healthier weight.