Public health officials and organizations have disseminated health messages regarding the dangers of obesity. However, these have not produced the desired effect.
In this study, researchers from the United States estimated the expected number of years of life lost (YLL) due to overweight and obesity across the life span of an adult.
The team used data from several sources to derive YLL estimates for adults aged 18 to 85 years:
- US Life Tables (1999).
- Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994).
- First National Health and Nutrition Epidemiologic Follow-up Study (NHANES I and II; 1971-1992).
- NHANES II Mortality Study (1976-1992).
The researchers used body mass index (BMI) integer-defined categories (i.e. <17, 17 to <18, 18 to <19, 20 to <21, 21 to 45, or 45).
A BMI of 24 was used as the reference category.
|Obesity in white men, aged 20 to 30 years, may represent up to a 22% reduction in expected remaining life span.|
|Journal of the American Medical Association|
The team determined the difference between the number of years of life expected if an individual were obese versus not obese. This was designated YLL.
The researchers observed marked race and sex differences in estimated YLL.
Among whites, the team identified a J- or U-shaped association between overweight or obesity, and YLL.
They determined that the optimal BMI (for greatest longevity) was approximately 23 to 25 for whites, and 23 to 30 for blacks.
They also found that for any given degree of overweight, younger adults generally had greater YLL than did older adults.
The maximum YLL for white men aged 20 to 30 years with a severe level of obesity (BMI >45) is 13. This figure is 8 YLL for white women aged 20 to 30.
For men, this represents up to a 22% reduction in expected remaining life span.
However, among black men and women older than 60 years, overweight and moderate obesity were generally not associated with an increased YLL. The team found that only severe obesity resulted in YLL in this situation.
In contrast, blacks at younger ages with severe levels of obesity had a maximum YLL of 20 for men, and 5 for women.
Dr Kevin Fontaine's team concluded, "Obesity appears to lessen life expectancy markedly, especially among younger adults".