NEW YORK (GenomeWeb) – A new analysis of UK Biobank study participant data suggests that common genetic variants and recommended lifestyle factors can independently contribute to the risk of experiencing a stroke.
Researchers from the German Center for Neurodegenerative Diseases (DZNE), the University of Cambridge, and elsewhere used data from the UK Biobank Study to assess the number of incident stroke events across 306,473 Caucasian participants, who ranged in age from 40 to 73 when they were enrolled in the UK Biobank study between 2006 and 2010. They found that stroke risk was related to a polygenic risk score based on 90 SNPs as well as adherence to recommended lifestyle factors such as regular exercise, a healthy diet, and non-smoking.
"In this cohort study, genetic and lifestyle factors were independently associated with incident stroke," first and corresponding author Loes Rutten-Jacobs, a researcher affiliated with DZNE and the University of Cambridge clinical neurosciences department, and her colleagues wrote in a study published online yesterday in BMJ.
The team noted that there were 2,077 ischemic strokes, intracerebral hemorrhages, or sub-arachnoid hemorrhages in the participants over a median of seven years of follow up. Stroke risk was roughly 35 percent higher in the almost 102,200 individuals with polygenic risk scores in the top third compared to those with the risk scores in the lowest third, regardless of lifestyle.
The researchers saw 785 high genetic risk individuals who developed incident stroke, compared to 589 stroke events in the group of nearly 102,000 individuals in the low genetic risk score group.
Those results support the notion that common genetic variants contribute to the odds of experiencing a stroke, the authors explained, and suggest these common variants can be encompassed in an informative polygenic risk score.
But the stroke risk was enhanced to an even greater extent by an unfavorable lifestyle. In a comparison of stroke risk between individuals with unfavorable and favorable lifestyles, the researchers reported a 66 percent rise in stroke risk in the poorer lifestyle group.
"The risk reduction associated with adherence to a healthy lifestyle in the present study was similar across all stratums of genetic risk," the authors wrote, "which emphasizes the benefit for entire populations of adhering to a healthy lifestyle, independent of genetic risk."
The stroke risk appeared to be far more pronounced for individuals with both a high polygenic risk score and lifestyle risk factors, the team reported. That group had roughly twice the risk of an incident stroke relative to the group with a low risk score and favorable lifestyle.
The researchers cautioned that the current results stem from individuals of European ancestry, and grouped various stroke types together. Consequently, they suggested, additional studies on more diverse populations are required to determine whether the results can be applied more broadly, and whether there are certain stroke causes with greater genetic or lifestyle components.