NEW YORK (GenomeWeb) – A healthy lifestyle can moderate genetic risk of heart disease, according to an international team of researchers.
Researchers led by Sekar Kathiresan from Massachusetts General Hospital found that people at a high genetic risk of coronary artery disease who followed a healthy lifestyle could reduce their risk of a coronary event by about half, as compared to those who did not follow a healthy lifestyle.
As they reported in the New England Journal of Medicine yesterday, the researchers analyzed the genetic and lifestyle factors of more than 55,600 people from four studies.
"The basic message of our study is that DNA is not destiny," Kathiresan said in a statement. "Many individuals — both physicians and members of the general public — have looked on genetic risk as unavoidable, but for heart attack that does not appear to be the case."
Kathiresan and his colleagues drew on four study populations: prospective cohorts from the Atherosclerosis Risk in Communities study, the Women's Genome Health Study, and the Malmö Diet and Cancer Study, as well as a cohort from the cross-sectional BioImage study. Some 5,100 coronary events were reported across these cohorts during follow-up.
For more than 51,400 participants from the three prospective cohorts, the researchers used a polygenic risk score based on 50 SNPs that previous studies linked to coronary artery disease to gauge participants' genetic risk of disease. Based on their scores, the researchers grouped the participants into high, intermediate, or low genetic risk groups.
For the three cohorts, the researchers calculated that participants with a high genetic risk of disease had a 91 percent higher relative risk of a coronary event as compared to participants with a low genetic risk of disease.
At the same time, Kathiresan and his colleagues gauged whether the participants adhered to four healthy lifestyle factors — not being a smoker, not being obese, getting regular exercise, and following a healthy diet — that are associated with a decreased risk of coronary events. They then also divided the participants into favorable, intermediate, or unfavorable lifestyle groups based on the number of healthy lifestyle factors that applied to them.
The researchers noted that participants with unfavorable lifestyles had higher rates of hypertension, diabetes, BMI, and disadvantageous levels of circulating lipids as compared to those with a favorable lifestyle. In addition, participants with unfavorable lifestyles had a higher risk of coronary events, independent of their genetic risk.
Still, within each genetic risk category, Kathiresan and his colleagues found that lifestyle factors were also strong predictors of coronary events. For instance, as compared to participants with an unfavorable lifestyle, those with a healthy lifestyle had a 45 percent lower relative risk of a coronary event within the low genetic risk group. Similarly, among the high genetic risk group, those with a healthy lifestyle had a 46 percent lower relative risk of a coronary event than those with an unfavorable lifestyle.
As lifestyle factors reduced risk by about the same percentage for each genetic risk category, the researchers said this suggested that public health efforts should stress the importance of a healthy lifestyle for everyone. At the same time, they further noted that a low genetic risk of disease could be offset by an unfavorable lifestyle.
Using data from the cross-sectional BioImage study cohort, the researchers found that both genetic and lifestyle factors were associated with coronary artery calcification, but that calcification appeared to decrease within each genetic risk group in participants who followed a healthy lifestyle.
"Some people may feel they cannot escape a genetically determined risk for heart attack, but our findings indicate that following a healthy lifestyle can powerfully reduce genetic risk," Kathiresan added. "Now we need to investigate whether specific lifestyle factors have stronger impacts and conduct studies in more diverse populations, since most of the participants in these studies are white."