The study is published in the April 1, 2008, issue of Neurology, the medical journal of the American Academy of Neurology.

We found a three-to-four-fold higher overall prevalence of cerebral microbleeds compared to other studies, according to study author Monique M.B. Breteler, MD, PhD, with the Erasmus MC University Medical Center in Rotterdam, the Netherlands. These findings are of major importance since cerebral microbleeds likely reflect cerebrovascular pathology and may be associated with an increased risk of cerebrovascular problems.

Cerebral microbleeds are lesions that can be seen on brain scans, such as an MRI brain scan. The lesions are deposits of iron from red blood cells that have presumably leaked out of small brain vessels.

For the study, 1,062 healthy men and women who were an average age of 70 underwent an MRI to scan for the presence of cerebral microbleeds. Of the participants, 250 were found to have cerebral microbleeds.

The study found overall prevalence of cerebral microbleeds was high and increased with age from 18 percent in people age 60 to 69 to 38 percent in people over age 80. People with the e4 allele of the APOE gene, which is known to increase the risk of Alzheimer's disease and of cerebral amyloid angiopathy, had significantly more microbleeds than people without this genetic variant.

We also found that the risk factors for cerebral microbleeds appear to vary according to the location of the microbleed, said Breteler. Our results show people with high blood pressure and a history of smoking had microbleeds in a different location in the brain than people with the APOE e4 allele, suggesting different causes for microbleeds in different locations.

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"These new variants, along with other recent genetic findings, provide a window into disease causation that may be our best hope for the next generation of therapeutics. By pinpointing particular pathways involved in diabetes risk, these discoveries can empower new approaches to understanding environmental influences and to the development of new, more precisely targeted drugs," said NHGRI Director Francis S. Collins, M.D., Ph.D., who is a co-author of the study. Dr. Collins' laboratory is a participant in the Finrisk 2002 and Finland-United States Investigation of NIDDM Genetics (FUSION), which were among the studies that contributed data to the new analysis. FUSION is funded by NHGRI?s Division of Intramural Research and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

Researchers said more work is needed to understand the impact of their discovery that a genetic variant called JAZF1 appears to be involved in diabetes as well as prostate cancer. One of the study?s lead authors, Eleftheria Zeggini, Ph.D., of the University of Oxford, said, "This is now the second example of a gene which affects both type 2 diabetes and prostate cancer. We don?t yet know what the connections are, but this may have important implications for the future design of drugs for both of these conditions."

The research was conducted by the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) consortium, which brought together many groups active in the field of diabetes research. In the Nature Genetics paper, DIAGRAM researchers combined the data from three previously published genome-wide association studies in an effort to boost the statistical power of their searches ” an approach that scientists refer to as meta-analysis. The strategy paid off, enabling researchers to identify six genetic variants associated with type 2 diabetes that had gone undetected in the smaller, individual studies.

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