Study objective: To study the effect of long-term smoking on all-cause and cause-specific mortality, and to estimate the effects of cigarette and cigar or pipe smoking on life expectancy.
Design: A long-term prospective cohort study.
Setting: Zutphen, The Netherlands.
Participants: 1373 men from the Zutphen Study, born between 1900 and 1920 and studied between 1960 and 2000.
Measurements: Hazard ratios for the type of smoking, amount and duration of cigarette smoking, obtained from a time-dependent Cox regression model. Absolute health effects of smoking are expressed as differences in life expectancy and the number of disease-free years of life.
Main results: Duration of cigarette smoking was strongly associated with mortality from cardiovascular disease, lung cancer and chronic obstructive pulmonary disease, whereas both the number of cigarettes smoked as well as duration of cigarette smoking were strongly associated with all-cause mortality. Average cigarette smoking reduced the total life expectancy by 6.8 years, whereas heavy cigarette smoking reduced the total life expectancy by 8.8 years. The number of total life-years lost due to cigar or pipe smoking was 4.7 years. Moreover, cigarette smoking reduced the number of disease-free life-years by 5.8 years, and cigar or pipe smoking by 5.2 years. Stopping cigarette smoking at age 40 increased the life expectancy by 4.6 years, while the number of disease-free life-years was increased by 3.0 years.
Conclusions: Cigar or pipe smoking reduces life expectancy to a lesser extent than cigarette smoking. Both the number of cigarettes smoked and duration of smoking are strongly associated with mortality risk and the number of life-years lost. Stopping smoking after age 40 has major health benefits.