Scientists say they have discovered a definitive link between certain lifestyle and demographic factors and a potential biomarker to determine the risk of type 2 diabetes, according to a study published in the journal Clinical Chemistry.

Researchers from the US and Japan say their latest research builds on previous studies that show how low levels of a protein called sex hormone binding globulin (SHBG) can be an indication of increased risk for metabolic syndrome and type 2 diabetes years in advance.

For the study, led by Dr. Simin Liu, the research team measured the levels of SHBG in 13,547 women who were a part of the national Women’s Health Initiative.

The researchers also measured non-genetic factors that could be linked to their SHBG levels. These included:

  • Age
  • Reproductive history
  • Usage of exogenous estrogen
  • Body mass index (BMI)
  • Physical activity
  • Alcohol consumption
  • Coffee intake
  • Smoking
  • Other dietary factors.

Results of the analysis revealed that age, use of estrogen replacement therapy, physical activity and coffee consumption were significantly higher in women with higher SHBG levels. However, women with a high BMI were linked to low SHBG levels.

Although the research team had previously found that SHBG levels are able to predict the risk of type 2 diabetes, and that several mutations in the genetic coding for the protein are also predictive factors, they say this research shows protein does not necessarily remain unchanged throughout our lives.

Dr. Liu, professor of epidemiology and medicine at Brown University, says:

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.”

Additionally, the research showed that the significant associations of SHBG in women did not vary between ethnic groups.

“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,” says Dr. Atsushi Goto, first author of the study and endocrinologist at the Japanese Diabetes Research Center of the National Center for Global Health and Medicine in Tokyo.

Dr. Liu says that it is important to track lifestyle and demographic links with SHBG levels, as they give doctors a point of reference on what SHBG levels could exist in patients.

The research could also lead to potential new interventions, as BMI, physical activity, estrogen therapy and coffee intake can all be adjusted. Dr. Liu notes that by knowing these factors are linked to the biomarker, this suggests changing these elements of lifestyle could, in turn, adjust levels of protein over time, therefore affecting the risk of diabetes.

Furthermore, the researchers note that the findings could help to explain possible physiological links between lifestyle factors and risk of type 2 diabetes.

They point out that previously, regular coffee consumption and lower BMI have been linked to lower risk of the condition. However, these most recent findings suggest that SHBG levels may intermediate between these links.

Liu says this may be because the protein is produced in the liver and therefore influences the body’s metabolism.

Dr. Liu says he is in support of the idea that the monitoring of SHBG levels should be added to the standard of preventive care for patients who are at risk of type 2 diabetes, as SHBG levels are already detectable through blood tests.

“By the time you are checking blood glucose it’s too late, [because] you use that as a diagnostic criterion to define diabetes,” he adds.

“Our argument is that you can go to the doctor’s office and check this protein that can predict your future risk 6 to 10 years down the line.”

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