Current and recent cigarette smoking in relation to cardiovascular and non-cardiovascular mortality in an elderly male Chinese population.

OBJECTIVE

To investigate the association between current and former smoking and the risk of mortality in elderly Chinese men.

METHODS

Our study participants were elderly (≥ 60 years) men recruited in a suburban town of Shanghai. Cigarette smoking status was categorized as never smoking, remote (cessation > 5 years) and recent former smoking (cessation ≤ 5 years), and light-to-moderate (≤ 20 cigarettes/day) and heavy current smoking (> 20 cigarettes/day). Cox proportional hazards models and restricted cubic splines were used to examine the associations of interest.

RESULTS

The 1568 participants had a mean age of 68.6 ± 7.1 years. Of all participants, 311 were never smokers, 201 were remote former smokers, 133 were recent former smokers, 783 were light-to-moderate current smokers and 140 were heavy current smokers. During a median follow-up of 7.9 years, all-cause, cardiovascular and non-cardiovascular deaths occurred in 267, 106 and 161 participants, respectively. Heavy current smokers had the highest risk of all-cause and non-cardiovascular mortality, with an adjusted hazard ratio (HR) of 2.30 (95% CI: 1.34-4.07) and 3.98 (95% CI: 2.03-7.83) versus never smokers, respectively. Recent former smokers also had a higher risk of all-cause (HR = 1.62, 95% CI: 1.04-2.52) and non-cardiovascular mortality (HR = 2.40, 95% CI: 1.32-4.37) than never smokers. Cox regression restricted cubic spline models showed the highest risk of all-cause and non-cardiovascular mortality within 5 years of smoking cessation and decline thereafter. Further subgroup analyses showed interaction between smoking status and pulse rate (≥ 70 beats/min < 70 beats/min) in relation to the risk of all-cause and non-cardiovascular mortality, with a higher risk in current versus never smokers in those participants with a pulse rate below 70 beats/min.

CONCLUSIONS

Cigarette smoking in elderly Chinese confers significant risks of mortality, especially when recent former smoking is considered together with current smoking.