Smoking not only shortens life but it also lowers quality of life, according to a Finnish study published in the Archives of Internal Medicine.

The study was conducted by Dr. Arto Y. Strandberg of the University of Helsinki and colleagues and involved 1,658 white men born from 1919 to 1934. The participants were healthy at the beginning of the study in 1974. They were followed for a period of 26 years at the end of which they were mailed follow-up questionnaires about their current smoking status, health, and quality of life.

Over the follow-up period, 372 men (22.4 percent) from the study participants had passed away. Non-smokers lived an average of 10 years longer than heavy smokers (“heavy” was defined as more than 20 cigarettes per day). Although 68.9 percent cessation rate during the follow-up period, 44.1 percent of the originally heavy smokers had died, the study found. Mortality increased significantly with the number of cigarettes smoked at baseline.

Another interesting finding of the study was that smoking not only affected life expectancy but also affected the quality of life, as “those who survived to the mean age of 73 years had a significantly lower physical health-related quality of life than never-smokers.”

Smoking remains the biggest avoidable cause of death and disability in the United States, David M. Burns, M.D. professor emeritus of family and preventive medicine at the University of California San Diego wrote in an accompanying editorial. According to current estimates, smoking kills more than 400,000 people each year.

Also, secondhand smoking seems to be higher than previously believed, killing almost 40,000 people annually because of cancers, respiratory infections and asthma, conditions diagnosed in the case of smokers as well. Smoking also favors conditions such as heart disease and child birth defects in case of women who smoke during pregnancy.