MILWAUKEE (AP) – Paul Ryan works out and watches his diet, but a new study shows that clean living can only go so far to help people like the vice presidential candidate overcome a strong family history of heart disease.

The study of 4 million people – the largest ever on heart risks that run in families — found that having a close relative die young of cardiovascular disease doubles a person's odds of developing it by age 50. This risk was independent of other factors like high cholesterol, high blood pressure and diabetes, and was even higher if more than one close family member had died young.

Ryan has said his father, grandfather and great-grandfather all died of heart attacks in their 50s, and the 42-year-old Wisconsin congressman has cited that as the reason for his devotion to exercise.