I don’t know how many unfiltered Chesterfields my grandfather smoked, but if you figure two packs a day for 75 years, it comes out to 1,095,000. He died on a Monday, at age 91, and he’d been at work the previous Friday. Outliers like that drive doctors crazy–but they can be useful for science. For decades, researchers have been trying to figure out what edge these folks possess in hope they may find a clue that can benefit the rest of us too.
Some of the most telling findings so far involve a study of nearly 500 long-lived Jews who were either born in the U.S. or emigrated after World War II. Their mean age was 97.3. Whatever these seniors did to manage such a longevity feat, it did not always include behaving well. More than 50% of the sample group were overweight or obese; 60% of the men and 30% of the women were long-term smokers at one point or another; and only half said they did even moderate exercise. “One of the women had been a smoker for 95 years,” says Dr. Nir Barzilai, director of the Institute for Aging Research at the Albert Einstein College of Medicine. But she also had four brothers and sisters, all of whom cracked 100.
This pattern of long-lived families played out across the group, and new research is uncovering why. So far Barzilai’s team has identified at least two gene sequences that help keep down bad cholesterol and raise good cholesterol. We all have those genes, but ours do not necessarily perform as well. The findings are already paying dividends. At least two drug companies are working on ways to mimic the effect of the genes.
None of this means good genes make bad health choices wise. I started smoking at 17, reckoning I had a genetic edge thanks to my grandfather. By my 20s, I could barely run a block without getting winded, and I quit smoking for good. Your genes are up to chance; your lifestyle’s up to you. It’s clear what the safer bet is.
This appears in the February 22, 2016 issue of TIME.