Income differences in life expectancy: the changing contribution of harmful consumption of alcohol and smoking.

BACKGROUND: Social differences in mortality have increased in high-income countries, but the causes of these changes remain unclear. We quantify the contribution of alcohol and smoking to trends in income differences in life expectancy from 1988 through 2007 in Finland.
METHODS: An 11% sample from the population registration data of Finns 25 years and older was linked with an 80% oversample of death records. Alcohol-attributable mortality was based on underlying and contributory causes of death on individual death certificates and smoking-attributable mortality on an indirect method that used lung cancer mortality as an indicator for the impact of smoking on mortality.
RESULTS: Alcohol- and smoking-attributable deaths reduced life expectancy by about 4.5 years among men. Alcohol-attributable mortality increased and smoking-attributable mortality decreased over the period 1988-2007, leaving the joint contribution stable. Among women, the contribution of these risk factors to life expectancy over the same period increased from 0.7 to 1.2 years. In 2003-2007, life expectancy differentials between the lowest and highest income quintile were 11.4 years (men) and 6.3 years (women). In the absence of alcohol and smoking, these differences would have been 60% less for men and 36% less for women. Life expectancy differentials increased rapidly over the study period; without alcohol and smoking, the increase would have been 69% less among men and 85% less among women.
CONCLUSIONS: Alcohol and smoking have a major influence on income differences in mortality and, with the exception of smoking among men, their contribution is increasing. Without alcohol and smoking, there would have been little change in life expectancy differentials.