Screening, Salt Iodization and the Epidemic of Thyroid Cancer in China: An Analysis of National Inpatient and Commercial Insurance Databases
22 Pages Posted: 27 Sep 2018More...
Background: Reasons behind the rapid increase of thyroid cancer (TC) in China are uncertain. Using two national databases, we assessed the burden of TC and the role of access to screening and salt iodization.
Methods: We analyzed data from Hospital Quality Monitoring System (HQMS) with 76,263,617 class 3 hospital inpatients in 2013-2017 and China Reinsurance Company (CRC) database with 93,123,018 clients in 2000-2016. Level of access to screening was assessed by the type of medical insurance of individuals and provincial Per Capita Disposable Income (PCDI). Iodine status of provinces was estimated by median urinary iodine (MUI). The proportion of TC inpatients among inpatients in HQMS and TC incidence in CII buyers were used to evaluate the association with screening and iodine status. We used the HQMS to estimate TC incidence in the general population.
Findings: Between 2013 and 2017 the proportion of TC patients in HQMS with urban employee medical insurance increased sharply while there was little change among those with the other two forms of medical insurance. The estimated incidence increased by 39.7% (23.9/100,000 to 33.4/100,000), with 1.98m new cases in class 3 hospitals. In CII buyers, the incidence increased by 57.2% (17.3/100,000 to 27.2/100,000) in 2013-2016. Across provinces, there was positive correlation between the proportion of TC inpatients in HQMS and PCDI. We found no association between the proportion of TC inpatients in HQMS in 2013-2017 and MUI in 1999 and 2005, but a negative correlation with MUI in 2011. Similar findings were observed in the CRC database. Interpretation: The epidemic of TC in China was substantially underestimated. It was associated with access to screening but not with salt iodization. In the absence of a very sharp reduction in screening activities, we forecast that 5.8 million healthy individuals would become TC patients unnecessarily between 2019 and 2030.
Funding: The World Health Organization (WHO Reference 2016/648722-0 and 2017/722356-0 for the China-World Health Organization Biennial Collaborative Projects 2016-2017) and National Natural Science Foundation of China (81772850).
Declaration of Interest: We declare no competing interests.
Ethical Approval: The ethics committee of the First Affiliated Hospital of Sun Yat-sen University approved the study.
Suggested Citation: Suggested Citation