It is modeled on the famous Framingham Heart Study, which helped spot cholesterol and other risk factors for heart disease.

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Participants came from the Framingham Heart Study, a large study that has been going on since 1948 to look at heart disease risk factors in Framingham, Massachusetts.

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Elderly women who lose that much height that fast have a 21% higher risk of hip fracture, said the study, which examined data from over 3, 000 adults from the Framingham Heart Study.

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Studies in this area have made use of large, defined cohorts, such as the Framingham Heart Study, to document risk factors in healthy populations, which are then followed for decades to see who develops heart disease.

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Because the Framingham Heart Study is not a randomized controlled trial, it's still not clear if vitamin D is the real reason for the link (the vitamin's levels could drop in unhealthy people for other reasons), or if taking a supplement would lower the risk.

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Meantime, leaders of the Framingham study say they are intrigued by digital's potential role in heart research.

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