Socio-economic factors and health care system characteristics related to thyroid cancer incidence in OECD countries

The thyroid cancer incidence in South Korea has been remarkably increasing. In female, the incidence had increased nearly ten-fold from 2002 to 2008, reaching 60 per million. Despite the increased incidence, thyroid cancer mortality in South Korea have not changed much and is similar to that of other countries which have lower incidence. It is proposed that the increased incidence may be due to the increased diagnosis with ultrasonography and fine needle aspiration cytology during this period. This study aims to analyze the influence of health care system characteristics on thyroid cancer incidence in OECD countries. Health care system characteristics(e.g., share of public health expenditure, percentage of specialists among doctors, number of diagnostic equipment per capita) as well as some socio-economic factors(e.g., GDP per capita, mean educational level, mean perceived health status) were derived from OECD Health Data and thyroid cancer incidence were obtained from GLOBOCAN over 33 OECD countries in 2002 and 2008. Based on the result from Hausman's test, a random-effect panel model was used to regress thyroid cancer incidence on health care system characteristics at country level as well as socio-economic factors. The same analysis was repeated with exclusion of South Korea. A pooled OLS regression was also employed to see if the results from panel analysis were robust. Share of public health expenditure was associated with lower thyroid cancer incidence(p<0.003 in male,p<0.001 in female). Higher GDP per capita(p<0.005 in male,p<0.027 in female), higher mean educational level(p<0.080 in male,p<0.015 in female) and lower mean perceived health status(p<0.060 in male,p<0.010 in female) were associated with higher incidence. With exclusion of South Korea, share of public health expenditure still had a significantly negative association with thyroid cancer incidence(p<0.027 in male,p<0.021 in female) even if the strength of association decreased slightly. In contrast, mean educational level became insignificant in male and mean perceived health status became insignificant in female. A pooled OLS regression confirmed the findings that, all other things being equal, the higher the share of public health expenditure, the lower the thyroid cancer incidence. Higher public expenditure on health seems to be associated with higher likelihood of avoiding unnecessary screening of thyroid cancer, though higher income and higher educational level facilitate utilization of thyroid cancer screening. It is necessary to find out how to alleviate the increasing thyroid cancer incidence since over-diagnosis of thyroid cancer can lead to unnecessary health spending and lower quality of life of population.