Studies of twins have found that about one-fourth of the variation in human life span can be attributed to genetics. That leaves about 75 percent that could be attributed to modifiable risk factors.

According to Laurel B. Yates, MD, MPH, Brigham and Women’s Hospital and colleagues studied a group of 2,357 men who were participants in the Physician’s Health Study. At the beginning of the study, in 1981 to 1984, the men (average age 72) provided information about demographic and health variables, including height, weight, blood pressure and cholesterol levels and how often they exercised. Twice during the first year and then once each following year through 2006, they completed a questionnaire asking about changes in habits, health status or ability to do daily tasks.

The study shows that41 percent lived to age 90 or older. Such an indication of numbers caused by Smoking, diabetes, obesity and hypertension significantly that “ reduced the likelihood of a 90-year life span, while regular vigorous exercise substantially improved it,” the authors write. “Furthermore, men with a life span of 90 or more years also had better physical function, mental well-being, and self-perceived health in late life compared with men who died at a younger age. Adverse factors associated with reduced longevity—smoking, obesity and sedentary lifestyle—also were significantly associated with poorer functional status in elderly years.”
The Brigham and Women’s Hospital announces that the researchers estimate that a 70-year-old man who did not smoke and had normal blood pressure and weight, no diabetes and exercised two to four times per week had a 54 percent probability of living to age 90.

However, if he had adverse factors, his probability of living to age 90 was reduced to the following amount:

Sedentary lifestyle, 44 percent
Hypertension (high blood pressure), 36 percent
Obesity, 26 percent
Smoking, 22 percent
Three factors, such as sedentary lifestyle, obesity and diabetes, 14 percent
Five factors, 4 percent