Objective: To investigate the impact of smoking on premature death in the Netherlands and the difference between causes of death for smokers and non-smokers.
Design: Observational cohort study.
Method: Data on smoking behaviour were obtained from 40,000 people who participated in the CBS (Statistics Netherlands) health survey between 2001-2006. These data were linked to data on death and cause of death for the 10 years following this questionnaire. Hazard ratios were calculated for premature deaths among smokers, classified into smoking intensity, and ex-smokers as compared with those who had never smoked. These data were used to estimate cumulative death of smokers versus non-smokers.
Results: The hazard ratio for premature death was 3.8 (95% CI: 3.2-4.5) for heavy smokers, 2.6 (95% CI: 2.2-3.0) for moderate smokers and 1.7 (95% CI: 1.3-2.3) for light smokers. Lifelong heavy smokers had a chance of 23% of dying before the age of 65. For moderate and light smokers and for non-smokers, the chance was respectively 16, 11 and 7%. For half of all people who died relatively young, cancer was the underlying cause of death. This was mainly lung cancer for smokers. Heavy smokers are estimated to have lost 13 years of life, moderate smokers 9 and light smokers 5. Smoking cessation at any age still benefited health. Ex-smokers who had quit before an approximate age of 35 had the same life expectancy as lifelong non-smokers.
Conclusion: An estimated four in ten premature deaths can be attributed to smoking in the Netherlands. Cancer is the predominant cause of death amongst smokers. Smoking cessation increases life expectancy. Therefore, the earlier a smoker stops, the better.