Breast cancer mortality in Chinese women: does migrant status play a role?

Purpose: It is unclear whether migration would affect the mortality risk of breast cancer. In this study, we compared breast cancer mortality among three Chinese populations: Guangzhou (GZ)-born women, Hong Kong (HK)–born women, and HK residents who were born outside HK (HK immigrant), with the aim to explore the impact of migrant status on breast cancer mortality. Methods: We applied an age–period–cohort model to annual age-specific mortality rates of breast cancer among GZ-born, HK-born, and HK-immigrant women from 2003 to 2016, respectively. We also projected mortality rates from 2017 to 2030. Results: Annual age-standardized mortality rate of breast cancer in women aged 35 years or older was 9.18, 9.17, and 9.83 per 100,000 population, for GZ-born, HK-born, and HK-immigrant women, respectively. A decreasing trend was found in the post-1950s cohorts of GZ-born women and in the post-1960s cohorts of two HK populations. Annual mortality rates of breast cancer in these populations were projected to decrease among the 35–64 years age group and increase among the 65 years and older age group in 2017–2030. Conclusions: We found higher age-specific mortality rates of breast cancer in HK-immigrant women compared with HK- and GZ-born women, suggesting that immigration status might have an impact on breast cancer mortality.