Subjects: Behavioral health
In the last 3 decades, Americans have reaped enormous health benefits by smoking less, but have lost ground due to weight gain and obesity, and their negative impacts on health. Ever wonder how these competing trends interact with each other?
Susan Stewart of Harvard University and colleagues tried to answer this question by forecasting life expectancy for a nationally representative 18-year-old assuming that recent trends in smoking and weight gain continued for the next decade or so.
The scientists estimated cigarette smoking trends over the last 30 years using data from the National Health Interview Survey, and BMI data from the National Health and Nutrition Examination Survey.
It turned out that the negative effects of increasing body mass index swamped the positive effects of cigarette smoking declines.
Specifically, continued declines in cigarette smoking would increase the life expectancy of an 18-year-old by 0.31 year by the year 2020. However, continued escalations in BMI would cut life expectancy by 1.02 years over the same period of time, with an overall net loss in life expectancy 0.71 years.
The scientists did mention that other factors such as better nutrition and education are likely to generate a very modest increase in life expectancy despite the impact of obesity, at least through 2020.
But at some point, the authors concluded, a failure to address continued increases in obesity could erode the steady gains made in health over the last century.
It’s “a bit of a wake-up call,” senior author Allison Rosen told the Los Angeles Times. “We have attributed so many of our health problems to smoking, and we’re getting health improvements from declines in smoking. But changes in the rates of obesity are starting to outweigh the declines in smoking.”
The write-up appears in the New England Journal of Medicine.