"It's a combination of your environment and heredity how long you live," she said. "Everybody who smokes points to that person who is in their 90s who is still smoking. But they are rare. Your genes will only carry you so far. After that, you are responsible. Few of us know what our genetic construction is. They will say, our parents lived into their 90s, but they may have had a less stressful lifestyle and didn't live in an urban environment exposed to toxic fumes."
Among the growing baby-boomers group, such research on aging is increasing, said Ruth Dunkle, a professor and gerontologist at the University of Michigan's School of Social Work.