Obesity Erodes Smoking Cessation Gains in US

Over the past 15 years, smoking rates in the US have declined by 20%, whereas obesity rates have increased by 48%.

A new analysis published in the New England Journal of Medicine by Susan Stewart and colleagues from Harvard University, Boston, MA, forecasts the effect of trends in obesity and smoking on future U.S. life expectancy and quality-adjusted life expectancy.

The researchers used data from the past three decades to forecast future rates of obesity and smoking and estimate their effects on length and quality of life.

The net effect of the declines in smoking and the increases in BMI for an 18-year old is a reduction in life expectancy of 0.71 years and a reduction in quality-adjusted life expectancy of 0.91 years relative to the trend. This pattern of results is seen for every year between 2005 and 2020 and becomes more pronounced over time.

The calculations assume that if past trends continue, almost half the U.S. adult population will meet the WHO criteria for obesity by 2020 (currently the obesity rate already exceeds 35% in some states).

Obviously, these forecasts are at a population level and do not apply to a particular person who loses weight or stops smoking.

While these results do not imply that life expectancy will fall, they do suggest that as a result of increasing obesity rates life expectancy will rise less rapidly than it otherwise would.

While these are US data, there is little reason to assume that similar trends will not also be apparent in other countries including Canada.

Clearly, policy makers will likely now need to address obesity with the same vehemence as they did smoking – unfortunately, finding and implementing effective policies to reduce obesity makes smoking bans look like a walk in the park (no pun intended).

Edmonton, Alberta