Genetic testing not useful for predicting Type 2 diabetes, study suggests

Ethnicity, family history and baseline blood sugar levels are better indicators, the lead researcher says.

Ethnicity, family history and baseline blood sugar levels are better indicators, McMaster doctor says

A man with diabetes consults a medical assistant in Seattle, Wash. A new study suggests that genetic testing is not the best way to predict who will develop the disease. (AP Photo/Ted S. Warren)

Genetic testing isn't the best way to predict who will develop Type 2 diabetes, a new study suggests.

An international team of researchers arrived at this conclusion after tracking health outcomes for more than 15,000 people on four different continents over and three-year period.

The researchers looked at whether 16 genetic markers that are believed to be related to Type 2 diabetes in Caucasians played a role in the development of the disease for people of other ethnicities, particularly, South Asians and self-identified Latinos. 

"The association between the genetic factor and diabetes was generally quite consistent across the ethnic groups," said Dr. Sonia Anand, a professor of medicine and epidemiology at McMaster University in Hamilton, Ont. and the study's principal investigator.

After making this discovery, the researchers, she said, wanted to find out  whether testing for these variants is an effective way to predict whether an individual will develop Type 2 diabetes.

"We said, 'How important is this genetic information? Is it better than the information we already use to predict diabetes, and that type of information includes things such as family history of diabetes? What the person's body weight is, do they have fat around the middle and things of that nature?' "

Dr. Sonia Anand is a a professor of medicine and epidemiology at McMaster University in Hamilton, Ont. (Supplied)

Poring over the data they gathered from study participants, the researchers discovered that other clinical factors were better predictors of who would end up developing the condition.

"At this point in time, we don't see that genetic information is useful to determine who will develop diabetes versus who will not in a large population," said Anand.

"It's probably just as effective for people to determine, their ethnicity, their fasting blood sugar and their family history."

Potential to turn genes 'on and off'

However, Anand didn't fully dismiss the value of genetic testing. She's working on a project to determine how the practice could help convince people who are risk of developing diabetes to adopt a healthy diet and exercise more.

Related: Pre-eclampsia, hypertension in pregnancy tied to higher diabetes risk

And she said the completed study, which was released on Friday in the journal Diabetes Care, would help researchers learn more about how to prevent and manage Type 2 diabetes.

"We have a number of ongoing studies looking at the interactions between genetic variables and lifestyle factors, like exercise and diet, and how these lifestyle factors may modify how the genes are expressed," Anand said.

"They have the potential of turning genes on and off, and that's a really exciting area of research which we are pursuing."