Researchers say that as obesity in America has risen dramatically in recent years -- and smoking rates have declined -- the contribution of obesity to the burden of disease and shortening of life has increased while smoking's role has decreased.
The study showed that from 1993 to 2008, the proportion of smokers among U.S. adults declined by 18.5% while the proportion of obese adults increased 85%.
Using information from nationwide annual health-related quality-of-life surveys conducted during the same time period, researchers calculated the Quality-Adjusted Life Years (QALYs) lost due to these two major health risk factors.
The results, published in the American Journal of Preventive Health, show that smoking-related QALYs lost remained relatively stable during this time period at 0.0438, or 16 days of healthy life lost per adult population.
Meanwhile, as the obesity epidemic increased the quality-of-life problems caused by obesity increased and accounted for 0.0464 QALYs lost.
Researchers say smoking had a bigger impact on deaths while obesity had a bigger effect on illness.
"Because of the marked increase in the proportion of obese people, obesity has become an equal, if not greater contributor to the burden of disease than smoking," write researcher Haomiao Jia, PhD, of Columbia University, and colleagues. "Such data are essential in setting targets for reducing modifiable health risks and eliminating health disparities."