Dr. Oz: What to Know About Your Family's Health History

Has anyone under 55 battled a chronic or severe illness?

It's important to know what diseases run in your family, but you also need to know when they started. A red flag is early onset, which is generally defined as ten to 20 years before serious conditions normally appear in healthy adults. A new Danish study found that people with a parent, sibling, or child who died from heart disease before age 60 were twice as likely to develop it. Alzheimer's disease is another one you should track—having a parent who developed it before age 65 means you have a 50 percent chance of inheriting a genetic mutation that may cause early onset of the disease. While Alzheimer's can't yet be prevented, it's still worth knowing if you're at risk. Scientists are constantly discovering new ways to prevent or slow the progression of certain incurable illnesses (a recent study suggests that a diet high in omega-3 fatty acids may prevent the development of Alzheimer's). Remember, this isn't about dwelling on mortality; it's about arming yourself with information that can improve and extend your life—and the lives of future generations.

What to Do if You Can't Talk to Your Family

1. Follow your paper trail.
Birth certificates will help you piece together your family tree. Death certificates—which list cause of death, age at death, and may even include chronic medical conditions—will help you gather clues for possible genetic links. If you don't have these documents, track them down at your local or state health department.

2. Check adoption agency records.
If you were adopted, go to childwelfare.gov/nfcad, where you can find state-by-state adoption registry information. Then contact the organization in the state where you were adopted to get help locating your file, which may include nonidentifying health information about your birth parents.

3. Consider your ethnicity.
Can't get any family records? Ask your doctor about diseases that may be linked with your ethnic background. For example, African-Americans are 1.8 times more likely to develop type 2 diabetes than Caucasians. Native Hawaiians also have a higher risk of type 2 diabetes, and if you're of Asian ancestry, you may be at high risk for developing osteoporosis.

Next: 10 simple habits that could help you live to 100