While people in Japan, Canada, and other nations are enjoying significant gains in life expectancy every year, most counties within the United States are falling behind, according to a new study by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington (Washington, USA). Between 2000 and 2007, more than 80% of counties fell in standing against the average of the 10 nations with the best life expectancies in the world, known as the international frontier.  Lead researcher and IMHE Director Christopher Murray observes that: “When compared to the international frontier for life expectancy, US counties range from being 16 calendar years ahead to more than 50 behind for women. For men the range is from 15 calendar years ahead to more than 50 calendar years behind. This means that some counties have a life expectancy today that nations with the best health outcomes had in 1957.”  Five counties in Mississippi have the lowest life expectancies for women, all below 74.5 years, putting them behind nations such as Honduras, El Salvador, and Peru. Four of those counties, along with Humphreys County, MS, have the lowest life expectancies for men, all below 67 years, meaning they are behind Brazil, Latvia, and the Philippines. As well, large disparities exist nationwide, as women fare more poorly than men. The researchers found that women in 1,373 counties – about 40% of US counties – fell more than five years behind the nations with the best life expectancies. Men in about half as many counties – 661 total – fell that far.  The researchers suggest that the relatively low life expectancies in the US cannot be explained by the size of the nation, racial diversity, or economics. Instead, the authors point to high rates of obesity, tobacco use, and other preventable risk factors for an early death as the leading drivers of the gap between the US and other nations.  Concluding that: “The US has extremely large geographic and racial disparities, with some communities having life expectancies already well behind those of the best-performing nations, the researchers urge that: “Efforts to address these issues will need to tackle the leading preventable causes of death.”