PROVIDENCE, R.I. [Brown University] Over the last decade researchers have amassed increasing evidence that relatively low levels of a protein called sex hormone binding globulin (SHBG) can indicate an elevated risk of type 2 diabetes and metabolic syndrome years in advance.
In a collection of studies described in a new paper, published online Sept. 18 in the journal Clinical Chemistry, Dr. Simin Liu, professor of epidemiology and medicine at Brown, led an effort to measure SHBG levels in 13,547 women who take part of the national Women's Health Initiative. The team comprehensively investigated nongenetic factors associated with levels of the protein. The researchers found that age, use of estrogen replacement therapy, physical activity, and caffeinated coffee drinking were significantly higher with higher SHBG levels. On the other hand, a high body-mass index (BMI) correlated with low SHBG levels.
Liu's group had previously established that SHBG can predict type 2 diabetes risk and identified several mutations in the genetic coding for the protein that are also predictive.
"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."
The researchers also made another important finding: SHBG's significant associations in women did not vary by ethnic group.
"This is the largest study conducted to date that shows that ethnic-specific differences concerning SHBG levels if any are not significant enough to warrant an ethnic specific reference for potential clinical application of this protein for diabetes risk stratification," said Dr. Atsushi Goto, first author and an endocrinologist at the Japanese Diabetes Research Center of the National C
|Contact: David Orenstein|