CHICAGO - Four common bad habits combined - smoking, drinking too much, inactivity and poor diet - can age you by 12 years, sobering new research suggests.

The findings are from a study that tracked nearly 5,000 British adults for 20 years, and they highlight yet another reason to adopt a healthier lifestyle.

Overall, 314 people studied had all four unhealthy behaviors. Among them, 91 died during the study, or 29 percent. Among the 387 healthiest people with none of the four habits, only 32 died, or about 8 percent.

The risky behaviors were: smoking tobacco; downing more than three alcoholic drinks per day for men and more than two daily for women; getting less than two hours of physical activity per week; and eating fewer than three fruits and vegetables daily.

These habits combined substantially increased the risk of death and made people who engaged in them seem 12 years older than people in the healthiest group, said lead researcher Elisabeth Kvaavik of the University of Oslo.

The study appears in the current Archives of Internal Medicine.

The healthiest group included never-smokers and those who had quit; teetotalers; women who had fewer than two drinks daily and men who had fewer than three; those who got at least two hours of physical activity weekly, and those who ate at least three fruits and vegetables daily.

"You don't need to be extreme" to be in the healthy category, Kvaavik said. "These behaviors add up, so together it's quite good. It should be possible for most people to manage to do it."

For example, one carrot, one apple and a glass of orange juice would suffice for the fruit and vegetable cutoffs in the study, Kvaavik said, noting that the amounts are modest and less strict than many guidelines.