[Mortality rates of foreign national residents in Japan: comparison with the Japanese population and a possible healthy migrant effect].

Objectives　This study clarified the health status of foreign nationals residing in Japan by comparing their current mortality rates with those of the Japanese population.Methods　We focused on foreign national residents and used official statistical data from 2010. Due to the possible overestimation of published death rates (PDRs), we computed calculated death rates (CDRs) for foreign national residents, using the number of registered foreign national residents as the denominator. We obtained this number from the Statistics on Foreign National Residents provided by the Ministry of Justice.Results　The all-cause age-adjusted mortality rates (per 100,000 population) of foreign national residents were 571.5 for men and 316.1 for women. The ratios with reference to the mortality rates of the Japanese population were 1.1 and 1.0 for men and women, respectively, indicating that the age-adjusted mortality rates for foreign national residents were similar to those of the Japanese population. However, the rate ratios by age group were 0.3-0.5 for those aged 20-34 years, 0.6-1.0 for those aged 35-59 years, and 1.0-1.4 for those aged ≥60 years, suggesting that the mortality rate of foreign national residents increases with age when compared to that of the Japanese population. Although the foreign population are thought to be disadvantaged in many ways, the mortality rates of the young and middle-aged groups were lower than those of the Japanese population. A similar tendency was observed in the cause-specific mortality rates of the young and middle-aged groups of foreign national residents, except the rates of mortality due to accidents and suicide in the middle-aged group, which were higher than those of the Japanese population. In those aged ≥60 years, the mortality rates were higher than those of the Japanese population overall, especially the mortality rates due to suicide.Conclusion　These results suggest that young and middle-aged foreign national residents are relatively healthy and that a healthy migrant effect exists in Japan. Because this health advantage may either decrease or converge with that of the native population after long-term residence as a previous research reported; without intervention, these lower mortality rates in the young and middle-aged foreign national residents may eventually increase or even exceed those of the Japanese population. More attention should be paid to middle-aged foreign national residents who have higher rates of mortality due to accidents and suicide as well as foreign national residents aged ≥60 years, who have an extremely high mortality rates due to suicide. Although overestimations and underestimations are still possible, CDRs are considered more appropriate than PDRs, since the impact is smaller. Future investigations should focus on the healthy migrant effect in Japan in order to address current and upcoming health issues among foreign national residents.