Smoking cessation and mortality trends among 118,000 Californians, 1960-1997

Area of Science:

• Epidemiology
• Public Health
• Cancer Research

Background:

• Long-term smoking is a major cause of mortality, particularly from lung cancer.
• Smoking cessation is widely promoted as a strategy to reduce these risks.
• Previous studies have shown benefits of quitting, but population-level impact requires ongoing assessment.

Purpose of the Study:

• To evaluate the impact of smoking cessation on all-cause and lung cancer death rates in a large cohort over 38 years.
• To compare mortality rates between cigarette smokers who quit and those who never smoked.
• To assess the population-level effect of widespread smoking cessation.

Main Methods:

• Analysis of a cohort of 51,343 men and 66,751 women from the American Cancer Society (ACS) Cancer Prevention Study (CPS I), enrolled in 1959.
• Follow-up for 38 years (until 1997) to track mortality outcomes.
• Comparison of age-adjusted death rates (per 1,000 person-years) between former smokers and never-smokers for all causes and lung cancer.

Main Results:

• For males, all-cause death rates decreased for both smokers and never-smokers, with smokers maintaining higher rates.
• For males, lung cancer death rates increased in both smokers and never-smokers, with smokers having substantially higher rates.
• For females, all-cause death rates increased for smokers and decreased for never-smokers; lung cancer death rates increased significantly for smokers.

Conclusions:

• Despite substantial smoking cessation, there was no significant decline in absolute or relative death rates from all causes and lung cancer for cigarette smokers as a whole compared to never-smokers.
• While smoking cessation reduces mortality risk for individuals, its overall population impact may be less than previously estimated.
• Further research is needed to understand the long-term population-level benefits of smoking cessation interventions.