Related Experiment Videos
A randomised controlled trial of the effect on middle-aged men of advice to stop smoking
Insights
Smoking cessation significantly improved chronic bronchitis symptoms in middle-aged men. However, the study suggests the life-saving benefits of quitting smoking might be overestimated compared to observational data.
Area of Science:
- Cardiorespiratory disease research
- Public health interventions
- Clinical trials
Background:
- Cardiorespiratory disease poses significant risks to middle-aged men.
- Smoking is a primary risk factor for cardiorespiratory disease and chronic bronchitis.
- Previous studies may have overestimated the mortality benefits of smoking cessation.
Purpose of the Study:
- To evaluate the effectiveness of a smoking cessation intervention in high-risk male smokers.
- To assess the impact of smoking cessation on cardiorespiratory symptoms and disease progression.
- To determine the long-term effects of smoking cessation on mortality.
Main Methods:
- A randomized controlled trial involving 1445 male smokers aged 40-59.
- Intervention group received personal interviews with a doctor for smoking cessation.
- Comparison group received "normal care"; follow-up included symptom assessment, ventilatory function tests, and mortality tracking.
Main Results:
- One-year cessation rate was 51% in the intervention group, with most others reducing smoking.
- Intervention group showed reduced sputum production and dyspnea; ventilatory function decline slowed.
- No significant effects on blood pressure or ECG findings; mortality rates were similar between groups over 7.9 years.
Conclusions:
- Smoking cessation effectively improved chronic bronchitis symptoms and disease progression in middle-aged men.
- The study indicates that the mortality benefits of smoking cessation may be less pronounced than suggested by observational studies.
- Further research is needed to fully understand the long-term impact of smoking cessation on cardiorespiratory mortality.
Abstract:
A randomised controlled trial of smoking cessation is reported in 1445 male smokers aged 40-59 at high risk of cardiorespiratory disease. The 714 men in the intervention group were recalled for a series of personal interviews with a doctor. After one year, 51% of the intervention group reported that they were not smoking any cigarettes, and most of the others reported a reduction. Compared with the "normal care" group, the men in the intervention group showed a decline in the prevalence of sputum production and dyspnoea; ventilatory function did not improve but its rate of decline was significantly slowed. There were no evident effects on blood pressure levels, nor on electrocardiographic findings over three years, nor on sickness absence over one year. Mortality follow-up has continued for an average of 7.9 years; 98 (13.7%) of the intervention group have died, compared with 94 (12.9%) of the "normal care" group. The 95% confidence limits on mortality range from 2.63% in favour of intervention to 4.37% in favour of normal care. The power of the trial has been reduced by smoking cessation in the "normal care" group. It is concluded that smoking cessation in these middle-aged men improved the symptoms and progress of chronic bronchitis; but the reversibility of the risk of cigarettes to the smoker's life may have been overestimated in observational studies.