Life expectancies in the United States lag behind some other high-income countries less because of things Americans are doing now than because of behaviors they have engaged in in the past.
Specifically, U.S life expectancies are lagging because of smoking. According to a report released by the National Research Council in January, heavy smoking in the past five decades is shortening American lifespans today.
“I think the report puts together a variety of evidence to answer a question that hadn’t really been asked before,” said Samuel Preston, PhD, co-chair of the council’s Panel on Understanding Divergent Trends in Longevity in High-Income Countries.
Over the past 25 years, life expectancy at age 50 in the United States has been increasing, but at a much slower rate than in some other high-income countries. According to National Center for Health Statistics 2007 data, the average life expectancy at birth today is 75.3 years for men and 80.4 years for women. To contrast, in Japan men live to an average age of 79.2 years and women to 86 years, as of 2006.
A group of seniors dances at a wellness center in Washington, D.C., in July 2010. While the average life expectancy for Americans is 77.9 years, the nation lags behind some other high-income countries because of factors such as past smoking.
Photo by Jahi Chikwendiu, courtesy The Washington Post/Getty Images
Researchers attribute the slower rate of increase — for women in the United States the increase was about 40 percent smaller than in other countries — to widespread smoking 30 to 50 years ago.
Over the period 1950 to 2003, the gain in life expectancy at age 50 was 2.1 years lower among U.S. women, compared with the average of nine other high-income countries, the report said. Women in the United States, on average, will live 5.7 years longer now than they would have in 1950. In the other nine countries, women are living an average of 7.8 years longer than in 1950.
“The damage caused by smoking was estimated to account for 78 percent of the gap in life expectancy for women and 41 percent of the gap for men between the United States and other high-income countries in 2003,” the report said.
Smoking rates in the United States are not nearly as high now as they were in the 1950s and 1960s, particularly for women, Preston said.
“American women led the world for years (in smoking),” Preston told The Nation’s Health.
And now, their life expectancy is increasing at a much slower rate than in other high-income nations.
Researchers also used smoking data to predict how life expectancy will be affected over the next two to three decades. Life expectancy for men will likely begin to improve “relatively rapidly” in coming decades because of reductions in smoking in the last 20 years, they said.
For women it is a different story. Women’s smoking behavior peaked later than men’s, so declines in mortality will likely remain slow for the next 10 years.
“What’s clear is that smoking histories matter, and smoking histories can’t be instantaneously reversed when you stop smoking,” Preston said.
The report also points to obesity as a possible contributer to the difference in U.S. life expectancy, but the authors said the links are less clear. However, the report said that if the obesity trend in the United States continues, it may offset the longevity improvement expected from reductions in smoking.
Mary Kleinman exercises in Pikesville, Md., in March 2010. If U.S. obesity trends continue, they may offset life expectancy gains that are predicted to occur in coming decades, a report found.
Photo by Melanie Stetson Freeman, courtesy Christian Science Monitor/Getty Images
The relationship between obesity levels and obesity risks “bears watching as an important factor in future longevity trends in the United States,” the authors wrote.
“We’re in the midst of a major increase in obesity, which could have long-term effects in itself,” Preston said.
The panel also examined whether differences in countries’ health care systems could explain the divergence in life expectancy over the past 25 years. It found that the United States’ lack of universal access to health care has increased mortality and reduced life expectancy, but Medicare entitlements for those older than 65 make lack of universal care a smaller factor.
Photo courtesy Gary Phillips, iStockphoto
“For main causes of death at older ages — cancer and cardiovascular disease — available indicators do not suggest that the U.S. health care system is failing to prevent deaths that would elsewhere be averted,” the report said.
In fact, Preston said the United States has better cancer detection and survival rates than most other high-income countries. Survival rates following a heart attack are also favorable in the United States, he said.
“Where something has gone awry is in prevention of diseases,” he said. “The (United States) has a very high incidence of chronic disease, though we seem to treat them very well once they occur. We’re not preventing some diseases as effectively as many of our peers.”
The report notes that smoking and obesity are “products of broad social and economic context,” in the United States, including residences and workplaces that encourage driving, levels of affluence that support large numbers of automobiles, low gasoline taxes and a climate and soil in part of the country that is conducive to growing tobacco.
The authors said that such factors are more common among people of lower social status and those who are less likely to have lifetime access to health care.
The report, “Explaining Divergent Levels of Longevity in High-Income Countries,” is available at www.nap.edu.
- Copyright The Nation’s Health, American Public Health Association
