According to researchers in Britain, men between the ages of 66 and 97 that smoke still lose about four years of life even if they reach the age of 70.

In the study, researchers Dr. Jonathan Emberson and Dr. Robert Clarke tracked the health of 7,000 men between the ages of 66 and 97 years old from 1997 to 2012  that participated in the Whitehall study of London civil servants. Hazard ratios for overall morality and a variety of causes of death related to smoking were calculated after age adjustment, employment grade and any previous diagnoses of vascular disease or cancer.

“Despite recent declines in the numbers of people smoking and tar yields of cigarettes, smoking remains the leading preventable cause of death in Europe,” Jonathan Emberson said in a press release.

He also added, “Previous studies had demonstrated that prolonged cigarette smoking from early adult life was associated with about 10 years loss of life expectancy, with about one quarter of smokers killed by their habit before the age of 70. Stopping at ages 60, 50, 40 or 30 years gained back about three, six, nine or the full 10 years. However, the hazards of continuing to smoke and the benefits of stopping in older people had not been widely studied.”

During the 15-year study, 5,000 of the 7,000 men died. Deaths among current smokers was about 50 percent higher than in those that had never smoked before. This was primarily due to vascular disease, respiratory disease and cancer.

Deaths in former smokers was 15 percent higher than in those that had never smoked, primarily a result of respiratory disease and cancer. In comparison to those that had never smoked, men who quit within the past 25 years had a 28 percent higher morality rate while men who quit more than 25 years ago had no significant risk.

Emberson says this study shows that active smoking continues to increase the risk of death in old age. The average life expectancy from 70 years old was about 18 years in men who had never smoked regularly, 16 years for men who quit before 70 years old and only about 14 years in men still smoking at age 70.

“This study shows that even if you were to ignore all the deaths caused by smoking before the age of 70, older smokers still do considerably worse than older non-smokers, losing a considerable amount of subsequent lifespan,” Emberson said.

A different study, conducted earlier this year, found that people who quit smoking before 40 years old can live as long as people who have never smoked a cigarette before.