FRIDAY, Sept. 20 (HealthDay News) -- Older women's age and lifestyle habits may be associated with levels of a protein possibly linked with type 2 diabetes risk, researchers say.

There is growing evidence that relatively low levels of the protein -- called sex hormone binding globulin (SHBG) -- can indicate an increased risk of type 2 diabetes years in advance.

"By the time you are checking blood glucose it's too late, [because] you use that as a diagnostic criterion to define diabetes," Dr. Simin Liu, a professor of epidemiology and medicine at Brown University, said in a university news release. "This protein can predict your future risk six to 10 years down the line."

Liu and his colleagues looked at more than 13,000 postmenopausal women and identified non-genetic factors associated with levels of SHBG. They found that age, use of estrogen-replacement therapy, physical activity and consumption of caffeinated coffee were significantly higher in women with higher levels of the protein.

However, a high body-mass index -- a measurement of body fat based on height and weight -- was associated with low SHBG levels.

The findings were published online Sept. 18 in the journal Clinical Chemistry.

Liu's group had previously found that SHBG can predict type 2 diabetes risk and identified several genetic factors associated with SHBG levels, according to the release.

"Even though there are genetic influences, this protein doesn't necessarily stay unchanged in each of us throughout our lives," Liu said. "This protein seems to capture the cumulative effect between the gene and our environment in reflecting a metabolic state of our body, particularly in the liver, ultimately affecting diabetes risk."

Liu and his colleagues also found that there are no racial or ethnic differences among women in terms of SHBG levels.

SHBG is readily detectable in blood samples and testing could be used in preventive care for patients at risk for type 2 diabetes, Liu said.

He also suggested that experiments could be conducted to determine if changing lifestyle habits -- such as getting more exercise -- could change SHBG levels over time and reduce a person's risk of diabetes.

More information

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