Inherited risks play significant disease role

Healthy aging

We are usually quite aware of the obvious attributes we inherit from our parents (curly hair, blonde hair or a pronounced absence of hair altogether as we age). But we are less aware of our genetic predisposition to the chronic diseases our parents had, until we get to around age 45. At least that’s my theory.

Here’s a truth. Our risk of any disease is greater, in some cases significantly greater, if one of our parents had it. The most frequently discussed diseases we inherit are diabetes, breast cancer, colon or ovarian cancer, heart disease and Alzheimer’s disease.

We share half of our genes with our "first degree" relatives (mother, father, siblings). For example, if your mother, father or an older brother has coronary artery disease, you have a 1.5 percent to 3 percent greater risk of getting the disease. If some of your "second-degree" relatives (grandparents, aunts, uncles, nieces and nephews) have the disease as well, your risk goes up. It’s fairly straightforward: more people, greater risk.

It probably goes without saying that if you have a family-load of relatives with a particular disease or condition, you exercise hardly at all and you are involved in a lifestyle that includes lots of salty French fries and copious amounts of red meat, your risk goes up even more.

Lifestyle matters, of course, but family matters more. Or perhaps I should say that family matters first. I came to this conclusion after reading an article in the Women’s Health Advisor, a publication put out monthly by the Weil Medical College at Cornell University. The researchers at Cornell recommend we acquire a greater awareness of family medical history. They make a strong case for an online tool that can help do that. It’s available at the American Society of Human Genetics at http://www.ashg.org/genetics/ashg/educ/007.shtml.

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Here’s a story that illustrates their point. A woman’s average lifetime risk for breast cancer is 11-12 percent, but a woman who carries the breast cancer gene has an average lifetime risk that can be as high as 85 percent. There are tests that allow you to find out whether you have the gene, but I’m suspecting that most daughters, sisters and brothers (don’t forget, men get breast cancer, too) don’t know that.

This is science — and it’s not. Recognition of the patterns in your own family medical history and improved awareness of available diagnostic and screening tools is important. But sometimes disease acquisition is chance.

Here’s another story. There’s a 25 percent greater likelihood you will get Alzheimer’s disease if a parent has the disease, but only 5 percent likelihood of the early-onset inherited form. And it is not uncommon at all for Alzheimer’s disease to occur without any known genetic link.

Which brings me back to lack of exercise and salty French fries. Now there’s something you can be absolutely sure about.

Sharon Johnson is an assistant professor in family and community development at OSU Extension and a member of the Senior Advisory Council. Reach her at s.johnson@oregonstate.edu.