The six-year study involved 3,885 community dwelling people over age 65 in Chicago, IL. Of the participants, nearly 25 percent were obese with a body mass index (BMI) over 30, and 37 percent were overweight with a BMI between 25 and 29.9. Four cognitive tests were given at the beginning of the study and every three years thereafter over the six-year period.

The study found no significant changes in memory or cognitive function throughout the study for overweight or obese participants. In fact, participants who were underweight had more cognitive decline over time.

We do not know yet why being overweight or obese does not increase the risk for cognitive decline in old age, however being underweight may be a correlate of the initial stages of Alzheimer's disease, said study author Maureen T. Sturman, MD, MPH, Rush University Medical Center and John H. Stroger Hospital of Cook County in Chicago. While past studies have found obesity in middle age increases a person's risk for dementia or Alzheimer's disease, our findings show obesity in old age has no effect on a person's memory. These findings are consistent with previous studies showing that weight loss or low BMI in old age may be a precursor of cognitive decline or Alzheimer's disease.

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According to the researchers, because NCBI's dbGaP Web site permits investigators to review patterns of statistical significance within the unfiltered genetic association tests across the entire human genome, researchers around the world will be able to rapidly access and potentially replicate or refute findings from the FHS 100K study or develop new hypotheses for further research.

The NCBI web site has the added advantage of linking into dozens of other databases, thereby providing access to other relevant human and animal data. The free exchange of data will accelerate the discovery of pathways to human disease, said Emelia J. Benjamin, MD, ScM, a professor of medicine at BUSM and one of the contributing authors.

The Framingham Heart Study 100K project has investigated hundreds of phenotypes and as such it is among the largest genome-wide association studies of its kind, representing the first set of genome-wide association findings from the FHS, notes Christopher J. O'Donnell, MD, MPH, FHS, associate director and senior advisor to the NHLBI director for genome research. These results set the stage for the launch of a much larger and more powerful NHLBI-funded genome-wide association study in the FHS known as SHARe (SNP Health Association Resource), which will be available in the fall of 2007.

Together, these projects will provide a number of opportunities for scientists to take advantage of the wealth of data collected by FHS over several decades in an ethically responsible way, added Daniel Levy, MD, FHS director.

The Framingham Heart Study dataset is another example of the groundbreaking collaboration of researchers from Boston University Schools of Medicine and Public Health and from the NHLBI, said Karen Antman, MD, dean of BUSM and provost of Boston University Medical Campus. Our researchers make extraordinary contributions that continuously improve the well-being of people all over the world.

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