Reducing health disparity in Taiwan: quantifying the role of smoking.

OBJECTIVE: To assess the impact of smoking disparities on health disparities, in terms of gap in life expectancy, in Taiwan cities and counties. METHODS: Using the decomposition method of life expectancy, the contribution of each disease category to the life expectancy gap was quantitatively expressed as the number of years of life. The smoking attributable fraction (SAF) was calculated for each city and county based on their respective smoking prevalence and relative risk for each smoking related disease. The smoking attributable gap (SAG) in life expectancy between two sites is the sum of the difference in SAF between two sites for each smoking related disease multiplied by the number of years this disease contributed to the life expectancy gap. RESULTS: Significant health and smoking disparities were present among the 23 cities and counties in Taiwan. These health disparities and smoking disparities were highly correlated (R2 = 0.3676). Generally, the health gap increased with increasing smoking disparity. The disparity in smoking prevalence and intensity among cities and counties in Taiwan was responsible for up to 19% of the health disparity. The health disparity is also highly correlated (R2 = 0.3745) with SAG in life expectancy. CONCLUSIONS: Reducing smoking is important to health, and reducing the smoking disparity is also important for reducing the health disparity observed in Taiwan. The larger the health disparity is, the more important the smoking attributable disparity could be. The reduction of smoking disparities could be a realistic and cost effective way toward reducing health disparities.