Mokhtar Soheylizad - PhD candidate, Student Research Committee, Hamadan University of Medical Sciences, Hamadan, Iran
Salman Khazaei - Assistant professor of Epidemiology, Vice-Chancellor for Research and Technology, Hamadan University of Medical Sciences, Hamadan, Iran.

Background and Aim: The relationship between age specific-rates of thyroid cancer (TC) and human development index (HDI) and also its components can be a new direction for planning by policy makers. This study aimed to identify the relationship between TC incidence and mortality rates by gender, and HDI and its components in different regions of the world.Methods: An ecological study was conducted; the data was obtained from the GLOBOCAN project in 2012. Inequality in TC estimates (age-specific incidence and mortality rates), according to the HDI and its components was calculated. Concentration index (CI) was used to estimate inequality and CI was decomposed to determine contribution of HDI and its components in inequality.Results: The concentration index was 0.29 (95% CI: 0.21 - 0.38) and -0.15 (95% CI: -0.23 - 0.06) for incidence and mortality of TC by HDI, respectively. The important contributors in inequality for incidence rates of TC were life expectancy at birth (0.30), mean years of schooling (0.26), and expected years of schooling (0.18). The important contributors in inequality of mortality rates were mean years of schooling (0.19), expected years of schooling (0.17), and urbanization (0.17).Conclusion: According to the results of this study, global inequalities exist in the TC incidence and mortality rates; incidence rates of TC are more concentrated in countries with high HDI, yet inequality index showed that deaths occurred more in disadvantaged countries.

Human Development Index, Thyroid Cancer, Decomposition