Aims: In Japan, smoking prevalence in males has been among the highest among industrialized countries, while the prevalence in females has remained relatively low. There have been long-term declining trends since the early 1970s. In the mid-1980s, the public tobacco monopoly was privatized and the tobacco market was liberalized in Japan. This study examines whether the trends in smoking prevalence changed at the time of these market changes.
Design and measurements: Smoking prevalence data, tabulated by age group and sex, were plotted over the period 1975-95. Trends of smoking prevalence were then analyzed by using linear regressions, and their changes at the time of monopoly privatization and market liberalization were examined by Chow tests.
Findings: The trends in smoking prevalence changed at the time of the monopoly privatization and trade liberalization in both males and females, except for the males in their twenties and thirties. Rates of decline in smoking prevalence diminished in many age groups and prevalence for younger females started to increase.
Conclusions: Market changes, that result from the privatization of a public tobacco monopoly and trade liberalization, may adversely affect smoking prevalence in many age groups and in both sexes, unless effective countermeasures are taken.