Oct. 13, 2008 -- Not only does smoking shorten life expectancy, it also has a significant impact on the quality of life in old age, according to a new study.

The Finnish study, published in the Archives of Internal Medicine, evaluated data on 1,658 white men born between 1919 and 1934 of similar socioeconomic status. They were participating in the Helsinki Businessmen study. At the start of the study, in 1974, all men were healthy. Their cardiovascular risks and smoking habits were evaluated at that time. The men were re-evaluated 26 years later through surveys. At that time, there had been 372 deaths.

Participants who had never smoked lived an average of 10 years longer than heavy smokers (defined as more than 20 cigarettes per day). The quality of life of the surviving participants was measured using a survey scale that measures health-related quality of life in categories including physical functioning, role limitations caused by health problems, role limitations caused by emotional problems, social functioning, emotional well-being, fatigue/energy, and general health perception.

The greatest difference was between those who had never smoked and heavy smokers. Two categories where the differences were particularly stark: physical functioning and role limitations caused by health issues.

Nearly 70% of the heavy smokers in 1974 had quit by 2000. However, the researchers write that the effect of smoking status at the start of the study still had a strong impact on death and quality of life.