The combined effect of smoking and frequent alcohol consumption on the risk of total death (a 34-year prospective cohort study in Tomsk)

To date, a vast body of evidence has accumulated regarding the adverse impact of smoking and excessive alcohol consumption on human health, as well as their association with increased mortality. At the same time, there is a lack of data from long-term prospective studies to assess the risk associated with the combined effect of smoking and frequent alcohol consumption on mortality. Objective. To evaluate the combined effect of smoking and frequent alcohol consumption on the risk of death based on the results of a 34-year prospective cohort study in Tomsk, Russia. Materials and methods. The study included 630 men and 916 women aged 20—59 years. Screening was carried out between 1988 and 1991. Smokers were defined as individuals who smoked at least one cigarette per day or were former smokers, whereas frequent alcohol consumers were defined as those who consumed alcohol several times a week. In 2022, an analysis of all-cause mortality examined the impact of smoking, frequent alcohol consumption, and their combination on the risk of death. Over 34 years of follow-up, 554 all-cause deaths were recorded. Results. The 34-year prospective cohort study demonstrated that smoking and frequent alcohol consumption are independent risk factors for all-cause mortality, and their combination is associated with a 3.45-fold increase in this risk. Frequent alcohol consumption in smokers aged 20—59 years further increases the risk of all-cause mortality by a factor of 1.6, and in the younger age group (20—39 years), it rises by a factor of 2.12. The patterns of excess mortality risk associated with frequent alcohol consumption in smokers were investigated. The strong predictive value of this indicator in determining the risk of all-cause mortality was demonstrated across all studied periods: 10, 20, 30, and 34 years. At the same time, a steady decline in this risk was observed, from an HR of 2.54 at the 10-year follow-up mark to 1.6 at the 34-year mark. The highest 34-year survival rate was observed in individuals without the studied risk factors (70.4%), whereas it was 50.5% in smokers without frequent alcohol consumption. The lowest survival rate was found in individuals with both risk factors (39.4%). Conclusions. The combination of smoking and frequent alcohol consumption is associated with a high risk of death from all causes, particularly among young adults. The identified patterns indicate the need to implement comprehensive preventive strategies aimed at modifying these addictive behaviors.