Blog | Tuesday, January 25, 2011

QD: News Every Day--America's longevity gap blamed on smoking, obesity


Americans spent more on health care than other countries and still lag in longevity, largely due to smoking and obesity. How much so was laid out by the National Institute on Aging, which estimated smoking caused 78% of the gap in life expectancy for women and 41% of the gap for men between the U.S. and other high-income countries (European Union, Australia and New Zealand, and Japan) in 2003.

Smoking was much more widespread 50 years ago in the U.S. than in Europe or Japan, the report states. Americans smoked more, and also more intensively. Consequences are still playing out in today's mortality rates. From 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 (5.7 vs. 7.8 years gained, respectively).

Reprinted with permission from Explaining Divergent Levels of Longevity in High-Income Countries, 2011 by the National Academy of Sciences, Courtesy of the National Academies Press, Washington, D.C.Trend in highest recorded level of male life expectancy achieved versus trend in life expectancy in the United States. Data from Oeppen and Vaupel (2002) [Supplemental tables]; Human Mortality Database (http://www.mortality.org/ [accessed December 8, 2010]).

Because there appears to be a lag of two to three decades between smoking and its peak effects on mortality, how smoking will affect life expectancy can be predicted for the next 20 to 30 years. Life expectancy for men in the U.S. is likely to improve relatively rapidly in coming decades because of reductions in smoking in the last 20 years, the report says. For U.S. women, whose smoking behavior peaked later than men's, declines in mortality are apt to remain slow for the next decade.

Reprinted with permission from Trend in highest recorded level of female life expectancy achieved versus trend in life expectancy in the United States. Data from Oeppen and Vaupel (2002) [Supplemental tables]; Human Mortality Database (http://www.mortality.org/ [accessed December 8, 2010]).

Obesity may account for a fifth to a third of the shortfall of life expectancy in the U.S. relative to the other countries studied, although there is still a good deal of uncertainty in the literature regarding possible trends. For example, while lung cancer deaths are a reliable marker of the damage from smoking, no clear-cut marker exists for obesity.

Increasing obesity in the U.S. may offset the longevity improvements expected from reductions in smoking. However, recent data suggest that the prevalence of obesity in the U.S. has leveled off, and some studies indicate that the mortality risk associated with obesity has declined.

Lack of universal access to health care in the U.S. also has increased mortality and reduced life expectancy, the report says, though this is a less significant factor for those over age 65 because of Medicare. Available indicators for cancer and cardiovascular disease, the main causes of death at older ages, do not suggest that the U.S. health care system is failing to avert preventable deaths. In fact, cancer detection and survival appear to be better in the U.S. than in most other high-income nations, and survival rates following a heart attack also are favorable.

Over the last 25 years, life expectancy at age 50 in the U.S. has been rising, but at a slower pace than in many other high-income countries, such as Japan and Australia. This difference is particularly notable given that the U.S. spends more on health care than any other nation. The National Institute on Aging asked the National Research Council to examine evidence on its possible causes.