New research conducted by University of Toronto scholars at Unity Health Toronto underscores the significant health improvements individuals experience upon quitting smoking, regardless of age.
Published in NEJM Evidence, the study reveals that individuals who cease smoking before reaching 40 years old can nearly match the life expectancy of non-smokers. Furthermore, even those who quit later in life see substantial gains, with close to non-smoker survival rates achieved within a decade, and half of these benefits realized within just three years.
Examining data from 1.5 million adults across the United States, United Kingdom, Canada, and Norway over a 15-year period, the observational study highlights the stark risks associated with smoking. Smokers aged 40 to 79 face a nearly threefold increased risk of premature death compared to non-smokers, translating to an average loss of 12 to 13 years of life.
Former smokers, however, significantly mitigate this risk, reducing their chance of death to just 1.3 times that of non-smokers, marking a 30% decrease. The study also emphasizes that quitting smoking, regardless of duration, correlates with extended survival. Even those who quit for less than three years can potentially add up to six years to their life expectancy.
Notably, the researchers found that quitting smoking substantially lowers the risk of mortality from vascular disease and cancer, although the reduction in respiratory disease-related deaths is slightly less pronounced, likely due to residual lung damage.
Despite global efforts to curb smoking rates, with a decline of over 25% since 1990, tobacco remains a leading cause of preventable death. To further combat this issue, the study suggests measures such as increasing excise taxes on cigarettes, a strategy long overdue in Canada and potentially beneficial in other nations as well. Additionally, cessation support programs encompassing clinical guidelines, patient resources, and a comprehensive health-system approach could prove instrumental in encouraging smoking cessation and improving public health outcomes.