Life spans in the U.S. lags behind its major high-income industrial peers largely due to Americans’ long history of smoking as well as to rising rates of obesity, according to a new report from the National Research Council (NRC).

In the U.S., life expectancy at birth was 80.8 years for women and 75.6 years for men in 2007. In France, life expectancy for women was 84.4 years and 77.4 for men. In Japan, it was almost 86 years for women and 79.2 for men.

“This difference is particularly notable given that the U.S. spends more on health care than any other nation,” the study noted.

The role of smoking plays an interesting role – although lighting up was much more common in the U.S. than in Europe or Japan three to five decades ago, the health consequences are only now showing up in national mortality rates.

“Smoking appears to be responsible for a good deal of the differences in life expectancy, especially for women,” the NRC said in a press release. “The habit also has significantly reduced life expectancy in Denmark and the Netherlands, two other countries with lower life expectancy trends than comparable high-income countries.”

Since there appears to be a lag of two to three decades between smoking and its maximum impact on mortality, NRC estimates that over the next 20 to 30 years the life expectancy for men in the U.S. “is likely to improve relatively rapidly... because of reductions in smoking in the last 20 years.

However, for U.S. women, whose smoking behavior peaked after that of the men, any fall in mortality rates are likely to remain slow for the next decade.

In a similar vein, life expectancy in Japan is expected to improve less rapidly because of that nation’s high recent rates of smoking.

The report also finds that obesity had a significant influence on lagging life expectancies in the U.S.

“While there is still uncertainty in the literature about the magnitude of the relationship between obesity and mortality, it may account for a fifth to a third of the shortfall in longevity in the U.S. compared to other nations,” NRC stated.

“And if the obesity trend in the U.S. continues, it may offset the longevity improvements expected from reductions in smoking.”

However, NRC noted, it appears 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.”

Life expectancy is the U.S. has also been reduced by the lack of universal access to health care -- although this is not quite as big a factor for the elderly (above 65) since they have access to Medicare.