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

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.

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.

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.

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.