As far as the life expectancy difference between the sexes, Xu says it's not clear whether genetics plays a role, but behavior probably does. "Men usually take more risks, and they participate in risky outdoor activities like climbing and scuba diving," he says. "Also, teenage boys do more high-risk activities, and they get in more car wrecks, than girls."
Among other findings of the 2012 mortality report:
•The age-adjusted death rate for the USA decreased 1.1% from 2011 to 2012 to a record low of 732.8 per 100,000 population. The report attributes much of the recent improvement in both death rates and life expectancy to reductions in deaths from such major illnesses as heart disease, cancer and stroke.
"I think the health of the U.S. population is improving," Xu says. "The death rates for heart disease and cancer, the two leading causes of death that account for 46.5% of all deaths, have been falling since 1999."
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•The 10 leading causes of death in 2012 were the same as in 2011: heart disease, cancer, chronic lower respiratory diseases, stroke, unintentional injuries, Alzheimer's disease, diabetes, influenza and pneumonia, kidney disease and suicide. Those 10 causes accounted for 73.8% of all deaths in the USA.
However, from 2011 to 2012, age-adjusted death rates declined significantly for 8 of the 10 leading causes of death. The rate for suicide rose and the rate for unintentional injuries was unchanged.