*It may be that the explosion of chronic diseases during the twentieth century is now taking a toll on American life expectancy. In 2007, the CIA World Factbook ranked the United States forty-fifth for life expectancy at birth, below countries like Israel, Jordan, Bosnia, and Bermuda. Future gains in life expectancy depend largely on how much we can extend life among the elderly—exceedingly difficult, when you consider that the incidence of diabetes in people over seventy-five is projected to increase 336 percent during the first half of this century.