Fifty years of the British Doctors Study: smokers lose ten years of life, quitting gives most of it back
After following 34,439 male doctors for 50 years, lifelong smokers died on average about 10 years earlier than never-smokers, and stopping at 60, 50, 40 or 30 recovered about 3, 6, 9 or the full 10 years.
The British Doctors Study began in 1951 with questionnaires to male doctors and followed them for mortality until 2001, with periodic resurveys of smoking habits. This 50-year report used the full cohort of 34,439 men.
Men born around 1920 who continued to smoke had about twice the death rate in middle age of never-smokers and lost about 10 years of life expectancy. The excess was largest for lung cancer, chronic obstructive lung disease and vascular disease. Cessation at age 60, 50, 40 or 30 gained about 3, 6, 9 or 10 years of life expectancy respectively.
The study, together with the 1954 and 1956 reports, was the foundation of tobacco control worldwide.
- Lifelong cigarette smokers lost about 10 years of life expectancy compared with never-smokers
- Stopping at 60, 50, 40 or 30 gained about 3, 6, 9 or 10 years respectively
- Probability of dying in middle age (35-69) was about 43% for smokers vs 15% for non-smokers in the 1920 birth cohort
- Lung cancer mortality rose with cigarettes per day and fell steadily after cessation
Smoking is the single largest preventable cause of cancer death, and quitting at any age helps, with the greatest gain from quitting young. Cessation support belongs in every cancer service, including lung screening programmes.
- Male British doctors only, a homogeneous and affluent group; absolute risks differ in other populations
- Historical cohort smoking high-tar cigarettes from youth; modern patterns differ
- Cessation effects are observational and subject to healthy-quitter bias
- Does not address e-cigarettes or smokeless products