Some risk factors for type 2 diabetes - such as obesity and family history of the condition - are well established. But in a new study, researchers from France explore the possibility that a person's risk of developing type 2 diabetes may be influenced by their blood type.
According to the research team, including Dr. Guy Fagherazzi of the Center for Research in Epidemiology and Population Health at the Gustave Roussy Institute in France, past studies have investigated the association between blood type and stroke, finding people with blood type AB are at higher risk.
In one study that found such an association, the researchers note there was also a higher number of diabetes cases among individuals with blood type AB. Other studies - although small - have reported similar findings. This led them to investigate the link between blood type and diabetes in a larger cohort.
Dr. Fagherazzi and colleagues analyzed data from 82,104 women who were a part of the French E3N study - a cohort of almost 100,000 female teachers that began in 1990.
From an analysis of health questionnaires the women completed, the team identified 3,553 women who received a diagnosis of type 2 diabetes between 1990 and 2008. Blood samples from the women were collected between 1995 and 1997.
Women with blood type B+ at 35% higher risk of type 2 diabetes
The results of the analysis - published in the journal Diabetologia - revealed that women with blood type A were 10% more likely to develop type 2 diabetes than women with blood type O, while women with blood type B were 21% more likely to develop the condition.
- Type 2 diabetes is the most common form of diabetes
- The condition occurs when the pancreas is unable to use insulin effectively, causing high blood glucose
- Type 2 diabetes is more common in African Americans, Latinos, Native Americans and Asian Americans/Pacific Islanders.
Women with blood type AB were found to be at 17% higher risk of type 2 diabetes than those with blood group O, but the researchers say this result was "not statistically significant."
The team then assessed the women's risk of diabetes by their Rhesus factor - the presence of Rhesus antigens in the blood. However, they found there was no difference in type 2 diabetes risk between those who were Rhesus positive (R+) and those who were Rhesus negative (R-).
Next, the team assessed the risk of type 2 diabetes by both women's blood type (A, B, AB or O) and Rhesus factor. Each possible combination was compared with blood group O negative (O-), as this is classed as a universal blood group because it has no A, B or Rhesus antigens present.
The researchers found that women who were blood group B positive (B+) were 35% more likely to develop type 2 diabetes than those with blood group O-. Women with blood group AB+ were at 26% higher risk of type 2 diabetes, those with blood group A- were at 22% higher risk and those with blood group A+ were at 17% increased risk.
The team says their findings for blood groups O-, B- and AB- were not statistically significant.
Commenting on their results, Dr. Fagherazzi says:
"Our findings support a strong relationship between blood group and diabetes risk, with participants with the O blood type having a lower risk of developing type 2 diabetes.
Therefore, the effects of blood groups should be investigated in future clinical and epidemiological studies on diabetes. Further pathophysiological research is also needed to determine why the individuals with blood type O have a lower risk of type 2 diabetes."
However, the team suggests a number of potential factors that might explain their findings. For example, they point out that blood grouping is linked to specific molecules related to type 2 diabetes. Another study has associated blood type with gut bacteria composition, which may be linked to type 2 diabetes.
Study author Dr. Françoise Clavel-Chapelon - also of the Center for Research in Epidemiology and Population Health at the Gustave Roussy Institute - acknowledges the fact that their study population only included women but notes that no biological mechanisms were identified that suggest their findings were sex-dependent.
"Information on the participants was self-reported, but this is unlikely to substantially affect the results," he adds.
Last month, Medical News Today reported on a study by researchers from the Harvard School of Public Health in Boston, MA, suggesting increased yogurt consumption could reduce the risk of type 2 diabetes.