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Blood Test May Predict Diabetes Risk

Scientists have identified 5 molecules in the blood that can foretell diabetes risk years before typical signs of the disease appear. The finding might help to identify at-risk people who could take steps to delay or halt the disease.

Diabetes is marked by unusually high levels of blood sugar. The sugar is normally converted into energy with help from the hormone insulin. Diabetes occurs when the body can’t properly produce or use insulin.

Type 2 diabetes, the most common form of the disease, develops gradually over many years. By the time it’s diagnosed, the insulin-producing cells in the pancreas may already be damaged. Several factors are known to raise the risk for diabetes, including excess weight and inactivity. But a more accurate indicator, such as molecular biomarkers in the blood, could lead to more targeted interventions.

Drs. Thomas J. Wang and Robert E. Gerszten and colleagues at Massachusetts General Hospital and Boston University analyzed blood samples gathered as part of the Framingham Offspring Study, a long-term community-based study sponsored by NIH’s National Heart, Lung and Blood Institute (NHLBI). The new analysis was funded in part by NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

Of more than 2,400 participants with no signs of diabetes in the early 1990s, about 200 went on to develop type 2 diabetes during the 12 years of follow-up. The original blood samples from this latter group were analyzed and compared to samples from age-matched participants who did not develop diabetes but had similar risk factors.

The scientists used an approach called metabolomics, which focuses on the unique mix of chemicals, called metabolites, that reactions throughout the body leave behind. These chemical fingerprints can provide clues to the body's health.

The researchers used new technologies to rapidly measure the levels of 61 amino acids and other metabolites in the blood samples. The results were reported in the March 20, 2011, advance online edition of Nature Medicine.

The researchers found that elevated levels of 5 amino acids — isoleucine, leucine, valine, tyrosine and phenylalanine — seemed to predict a future diagnosis of diabetes. High levels of these amino acids were detected up to 12 years before onset of disease. Further analysis showed that a combination of 3 amino acids was an even better predictor of diabetes risk. The scientists confirmed their results by analyzing blood samples from more than 300 participants in an independent study of cancer and diet.

Even in participants closely matched for traditional risks factors, such as obesity, these amino acid levels could help differentiate people at greatest risk. Participants with the highest levels of the 3 most predictive amino acids were 4 to 5 times more likely to develop diabetes than those with the lowest levels.

"These findings could provide insight into metabolic pathways that are altered very early in the process leading to diabetes," says Wang. "They also raise the possibility that, in selected individuals, these measurements could identify those at highest risk of developing diabetes so that early preventive measures could be instituted."

— by Vicki Contie