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Abstract
Aims We studied the health consequences of quitting smoking before age 43 by time since quitting, number of years smoked and cigarettes smoked per day. The outcomes were all-cause, ischaemic heart disease and lung cancer mortality.
Design Prospective study.
Setting Norwegian counties.
Participants Men and women aged 40–43 years who participated in a national cardiovascular screening programme and who were followed from 1985 to 2018.
Measurements Self-reports from questionnaire on time since quitting smoking, years smoked and number of cigarettes per day, and measurements of height, weight and blood pressure, and a blood sample where serum was analysed for total serum cholesterol and triglycerides.
Findings The all-cause mortality rate was 30% higher among quitters less than 1 year ago compared with never smokers (adjusted HR=1.30, 95% CI 1.18–1.43 in men and HR=1.31, 95% CI 1.16 to 1.50 in women). Quitters who had smoked longer than 20 years had 23% higher mortality in men (HR=1.23, 95% CI 1.14 to 1.34) and 32% higher mortality in women (HR=1.32, 95% CI 1.18 to 1.49). Past smoking of more than 20 cigarettes/day was associated with HR=1.14 (1.05–1.23) in men and HR=1.16 (1.01–1.32) in women. The HR for lung cancer was 6.77 (95% CI 4.86 to 9.45) for quitting men who had smoked for more than 20 years compared with never smokers. The corresponding figure for women was 5.75 (95% CI 4.08 to 8.09).
Conclusions The mortality among quitters was close to that of never smokers, except for a higher mortality for lung cancer, which on the other hand was much lower than the lung cancer mortality in current smokers.
- harm reduction
- smoking caused disease
- cessation
- prevention
Data availability statement
No data are available.
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Data availability statement
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Footnotes
Twitter @aatverdal
Contributors AT is responsible for the overall content and is the guarantor of the paper. AT, RS and DST conceptualised and designed the study and revised the manuscript. AT drafted the initial manuscript. AT, RS and DST critically reviewed the manuscript for intellectual content. AT, RS and DST approved the final revised manuscript and agree to be accountable for all aspects of the work.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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