Socioeconomic Pattern of Smoking in Japan: Income Inequality and Gender and Age Differences

Purpose To elucidate the influence of individual socioeconomic status on smoking in Japanese adults. Methods Using a nationally representative sample (20,206 men and 21,093 women aged 18 to 54 years), the relation between smoking and socioeconomic characteristics was analyzed by sex and age group (18 to 24, 25 to 39, and over 40 years). Results The smoking prevalence was 57.0% for men and 16.6% for women. Living in an urban area was a negative factor for smoking in men, while a positive factor in women. Being married was positively associated with smoking in the younger population, but negatively associated in the older population. A relation between lower income and smoking was found in all groups, except in men aged 18 to 24 years. The income-related difference was most pronounced in the population aged 25 to 39 years: OR of smoking for the highest income quintile compared with the lowest was 0.60 (95% CI, 0.51–0.71) for men and 0.29 (95% CI, 0.23–0.35) for women. Conclusions Socioeconomic status, especially income, substantially predicted smoking in the Japanese population, while the impact differed according to sex and age groups. Effective anti-smoking strategies require consideration of the gender and age differences in the socioeconomic pattern of smoking.