August 21, 2012
Less Smoking Trumps More Obesity
Since the 1950s and 1960s, the number of cigarettes smoked in the United States has plummeted by one-half but the number of obese Americans has tripled.
So which megatrend has a greater impact on U.S. health and life expectancy? Remarkably, the winner is the positive effect of the decline in smoking. And the additional longevity, as fewer Americans light up, will continue to play out at least through 2040, according to new research.
“The advantages of smoking reductions are expected to outweigh the disadvantages of increases in obesity for both sexes,” according to findings by University of Pennsylvania sociologist Samuel Preston and his colleagues at UPenn’s Population Studies Center and at Emory University’s Department of Global Health.
The declining popularity of smoking has driven down deaths due to lung cancer to 18 percent of all U.S. deaths. But currently obesity is nearly running neck and neck, causing 16 percent of all deaths.
“We have a horse race going on,” said Christopher Ruhm of the University of Virginia’s Batten School of Leadership and Public Policy, who commented on Preston’s paper at the Retirement Research Consortium’s conference in Washington earlier this month. “The winner of the horse race is that the smoking effect is going to dominate.” (The Center for Retirement Research, which sponsors this blog, is a consortium member.)
Estimates of longevity, in this particular case, should be viewed with caution. The mortality impact isn’t easy to calculate, Ruhm and Preston said, because many conflicting things are going on at the same time. For example, although obesity is rising, cholesterol-lowering statins and blood pressure medications are reducing the risk that any individual will die from obesity.
Also, the effects of cigarette smoking are extremely difficult to measure, because mortality depends on so many factors, including the length of time someone smokes and how many cigarettes they smoke per day – or whether they smoke filter cigarettes or not.
The positive impact on men of these combined effects is greater than for women. For 40-year-old men living today, their U.S. life expectancy is about 78. By 2030, due to the combined impact on men of changes in smoking and obesity patterns, they will live eight months longer; by 2040, that will increase from eight to 11 months. These estimates do not account for the impact of factors other than smoking and obesity that also affect how long people live.
Women, who were slower to cut back on smoking and have done so to a lesser degree than men, will experience those health benefits later. Women who are now 40 have a longer life expectancy than men – age 82 – but obesity patterns will actually decrease that life expectancy slightly through 2020.
By 2030, however, the beneficial effects of smoking reductions will begin to dominate and will cause women’s longevity to rise slowly, by more than one month. By 2040, their longevity gains will be more pronounced – more than six months– as smoking’s decline continues to improve women’s health.
Full disclosure: The research cited in this post was funded by a grant from the U.S. Social Security Administration (SSA) through the Retirement Research Consortium, which also funds this blog. The opinions and conclusions expressed are solely those of the blog’s author and do not represent the opinions or policy of SSA or any agency of the federal government.