Considerable improvements have been made in the health of the population of the United States in the last three decades owing to healthy living interventions, specifically a reduction in smoking. However, during the same period, substantial increases in the incidence of overweight and obesity have adversely impacted the health of the same population. A new study in the New England Journal of Medicine (NEJM) reports that the negative effects of the obesity epidemic, if it continues, will virtually destroy the positive gains made by smoking cessation and prevention programs.

The authors of the NEJM study forecasted life expectancy and quality-adjusted life expectancy for a representative 18-year old, assuming that current trends in obesity and smoking continue. In most of the scenarios examined, the negative effects of overweight and obesity outweighed the positive effects of a decline in the rates of smoking. The average 18-year old today would gain 0.31 years of life expectancy owing to the decline in smoking; at the same time, he will lose more than 1 year owing to the rise in overweight and obesity. Overall, the authors concluded that the average 18-year old today would lose 0.71 years of life, or 0.91 quality-adjusted years, by the year 2020. If all adults in the United States became nonsmokers of healthy weight by 2020, the life expectancy of the average 18-year old would increase by almost 4 years, or more than 5 quality-adjusted years.

The increase in overweight and obesity has increased dramatically in the last 30 years, but the prevalence differs among gender, race, and age cohorts. The prevalence of obesity is approximately 35% among white men, black men, and white women, but is 55% among black women. The mean age of obese men and women is also rising, to 49 years among white and 44 years among blacks. The population of the United States is gaining years and pounds, and the disability and health care burden associated with an aging obese population are significant.

Everyone knows smoking kills; nonsmokers live up to 10 years longer than smokers. However, smoking does not cause the disability that comes with overweight and obesity. While obesity does not lead to quite the same decrease in life expectancy — 6 to 7 years on average, the quality of the life is significantly decreased compared to people of healthy weight. Overweight and obese people will spend 3 to 5 years of their life with significant disability owing to obesity-related conditions and have reduced functioning in their activities of daily living.

Still, one study concluded that unhealthy living is unhealthy living, regardless of whether that living is related to smoking or obesity. People who make unhealthy lifestyle choices will have a lower life expectancy than healthy-living cohorts, even if they eliminate smoking and obesity. Other vices, as well as unmodifiable factors like race, gender, and age, contribute to life expectancy and quality of life.

Both smoking and obesity are unhealthy lifestyle choices and are risk factors for a large burden of disease. By the year 2020, smoking is expected to decline by 21%, but 45% of the population will be obese. Targeted medical and public health interventions to control the obesity epidemic are needed to reclaim the gains made in healthy living through smoking cessation and prevention programs.

References

Lubetkin, E., & Jia, H. (2009). Health-Related Quality of Life, Quality-Adjusted Life Years, and Quality-Adjusted Life Expectancy in New York City from 1995 to 2006 Journal of Urban Health, 86 (4), 551-561 DOI: 10.1007/s11524-009-9344-9

Stewart, S., Cutler, D., & Rosen, A. (2009). Forecasting the Effects of Obesity and Smoking on U.S. Life Expectancy New England Journal of Medicine, 361 (23), 2252-2260 DOI: 10.1056/NEJMsa0900459

Reuser, M., Bonneux, L., & Willekens, F. (2009). Smoking Kills, Obesity Disables: A Multistate Approach of the US Health and Retirement Survey Obesity, 17 (4), 783-789 DOI: 10.1038/oby.2008.640

Wang, Y., Colditz, G., & Kuntz, K. (2007). Forecasting the Obesity Epidemic in the Aging U.S. Population** Obesity, 15 (11), 2855-2865 DOI: 10.1038/oby.2007.339

van Baal, P., Hoogenveen, R., de Wit, G., & Boshuizen, H. (2006). Estimating health-adjusted life expectancy conditional on risk factors: results for smoking and obesity Population Health Metrics, 4 (1) DOI: 10.1186/1478-7954-4-14