This week’s New England Journal of Medicine has a report of a study that shows that you can beat heart attacks to a great degree even if you lost the lottery for genes. (1)
It has been known for a long time that some people are prone to coronary heart disease because it runs in their family. And this increased risk is largely independent from the other known risk factors like elevated LDL (bad) cholesterol. It has more recently been discovered that this increased risk can be correlated with measurable genetic variables and the more of these genes you have the worse the prognosis. The question arises – is it hopeless for these people with bad genes or should they be trying even harder than the lucky ones.
Groups of investigators from several medical centers using information from 55,685 participants from 4 different prior studies have shown that you can make a difference with healthy lifestyle even if you got bad genes. Using 50 single-nucleotide polymorphisms (SNPs) that have been shown to be associated with coronary artery disease in previous studies they were able to make a very accurate score of the risk for these 55,685 men and women aged in their 50s and 60s. Then, 4 healthy lifestyle factors were determined- smoking, obesity, exercise and diet. The more of those 4 things you got right the lower your chances of having bad coronary events. Furthermore, the higher your genetic risk the greater the relative benefit, such that in the worst genetic risk categories there was an almost 50% reduction in bad outcomes with the best lifestyle score.
Taken individually the hazard ratios for these 4 lifestyle factors were very different. For not smoking by itself there was about a 50% reduction in hazard. So if you smoke you might as well be playing Russian roulette. Obesity was the second worst with a 33% reduction in risk for not being obese. Exercisers got a 22% reduction and the least helpful was a healthy diet with a 9% reduction in risk. So these things are not additive and hard to really tease apart from each other. But the real question is how hard are they to fix. It is notoriously hard to quit smoking and obesity is for all intents and purposes unfixable without surgery. Obesity is also genetic. The two least helpful things, exercise and eating right, are easier maybe. Also these things are sloppy to measure. What if you really exercise a-freakishly-lot? What if you eat really well? Finally, there are other things like high blood pressure and diabetes that are were not studied here.
It is probably not reasonable to measure your genetic risk exactly because we all should be doing those things that our mothers have been telling us. But if you come from a bad family you should be doing the right lifestyle even harder.
John DiTraglia M.D. is a Pediatrician in Portsmouth. He can be reached by e-mail- firstname.lastname@example.org or phone-354-6605.