Dr. Jonathan Emberson and Dr. Robert Clarke, coordinator of the study, said they evaluated information on 7,000 older men -- mean age 77 -- from 1997-2012 who took part in the Whitehall study of London civil servants.
Hazard ratios for overall mortality and various causes of death in relation to smoking habits were calculated after adjusting for age, last known employment grade, and previous diagnoses of vascular disease or cancer.
During the 15-year study, 5,000 of the 7,000 men died, but deaths in current smokers were about 50 percent higher than in those who never smoked due chiefly to vascular disease, cancer and respiratory disease.
"Despite recent declines in the numbers of people smoking and tar yields of cigarettes, smoking remains the leading preventable cause of death in Europe," Emberson said in a statement.
"Previous studies demonstrated prolonged cigarette smoking from early adult life was associated with about 10 years loss of life expectancy, with about a quarter of smokers killed by their habit before the age of 70. Stopping at ages 60, 50, 40 or 30 years gained back about 3, 6, 9 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."
Average life expectancy from age 70 was about 18 years in men who had never regularly smoked, 16 years for men who gave up smoking before age 70, but only about 14 years in men still smoking at age 70. Two-thirds of those who never smoked, but only half of current smokers, survived from age 70 to age 85, the study said.
"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.
The findings were presented at the European Society of Cardiology Congress in Amsterdam.