Smoking and life expectancy among U.S. veterans

Area of Science:

• Epidemiology
• Public Health
• Gerontology

Background:

• Smoking remains a leading cause of preventable mortality worldwide.
• Understanding the long-term impact of smoking on life expectancy is crucial for public health interventions.
• Previous studies, such as Hammond's findings, indicated significant life expectancy reductions associated with smoking.

Purpose of the Study:

• To estimate life expectancies for different smoking groups (current smokers, ex-smokers, nonsmokers).
• To quantify the impact of smoking intensity and age of initiation on life expectancy.
• To compare the life expectancy of ex-smokers with current smokers and nonsmokers.

Main Methods:

• A 16-year mortality follow-up study.
• Involved a large cohort of 198,820 U.S. veterans.
• Analysis stratified by smoking status (never smoker, ex-smoker, current smoker) and smoking intensity.

Main Results:

• Life expectancy showed an inverse relationship with the number of cigarettes smoked daily.
• Heavy smokers (40+ cigarettes/day) experienced the most substantial life expectancy reduction compared to nonsmokers, up to 9 years at younger ages (35-40).
• Earlier age of smoking initiation was associated with lower life expectancy.
• Ex-smokers who quit for reasons other than medical advice had a smaller life expectancy gap compared to nonsmokers than current smokers did.

Conclusions:

• Smoking cessation, regardless of the reason, is associated with improved life expectancy compared to continued smoking.
• The findings reinforce the significant negative impact of smoking on longevity.
• This study validates and extends previous research on smoking and mortality.