“Recent studies have found associations between beta-2 microglobulin and heart disease,” said Pamela Rist, Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts. “However, less is known about the association between beta-2 microglobulin and ischaemic stroke.”
The researchers looked at women with a mean age of 61 years enrolled in the Nurses’ Health Study who provided blood samples between 1989 and 1990 and who had no history of stroke or cancer. Participants were asked to complete questionnaires about their lifestyle and medical history every 2 years.
To learn more about beta-2 microglobulin and any possible link to stroke, the researchers measured the protein levels in 473 study participants who later had an ischaemic stroke as well as 473 participants of the same age who did not have a stroke. They were also matched based on other factors that could affect stroke risk, such as whether they smoked or used hormone treatments. The strokes occurred an average of 9 years after the start of the study.
Results showed that participants who later had an ischaemic stroke had higher levels of beta-2 microglobulin than those who did not have a stroke. The average level of the protein was 1.86 mg/L in those who had ischaemic strokes, compared with 1.80 mg/L in those who did not have a stroke.
The researchers divided the participants into 4 groups based on their levels of the protein. Those in the highest quarter of beta-2 microglobulin levels were 56% more likely to have a stroke than those in the bottom quarter. In the top quarter, 163 of the 283 women had strokes, compared with 106 of the 227 women in the bottom quarter.
The results were adjusted for other factors that could affect stroke risk, such as physical activity, high blood pressure and diabetes.
Rist said that limitations of the study are that it was conducted mainly among white women and that it could not examine any changes in protein levels.
“Given the high rate of disability from stroke, it is important to identify people who may be at higher risk of this disease,” she said. “This protein could be a marker that might help us in the fight against stroke. Further studies are needed to determine if beta-2 microglobulin levels can be modified through lifestyle changes.”
SOURCE: American Academy of Neurology