Gaining a few more years of healthy life would be great for individuals, but expensive for Medicare, researchers say. iStockphoto.com hide caption

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Percentage of deaths each year due to neonatal disorders around the globe. Courtesy of the Institute for Health Metrics and Evaluation hide caption

itoggle caption Courtesy of the Institute for Health Metrics and Evaluation

Students paste red ribbons on a window to mark World AIDS Day in Nanjing, China, in 2006. Although many infectious diseases have declined in the country, the number of new HIV cases nearly quadrupled between 2007 and 2011. AP hide caption

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Health researchers say the proportion of people in their late 40s to 60s with diabetes, hypertension or obesity has increased over the past two decades. iStockphoto.com hide caption

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