We think of poor nutrition, lack of exercise, and the genes we inherit from our parents as the major risk factors for diseases. But, by monitoring the age at which people are diagnosed with different diseases, we know that aging itself is the main risk factor for cancer, cardiovascular disease, Alzheimer’s, and many other diseases. According to recent data, the probability that a twenty-year-old woman will develop breast cancer within the next ten years of her life is roughly 1 in 2,000. The risk is 1 in 24 for a seventy-year-old woman—that’s an increase by almost a factor of 100.
