Methodology in the GBD study of China

We found the Article by Maigeng Zhou and colleagues1Zhou M Wang H Zeng X et al.Mortality, morbidity, and risk factors in China and its provinces, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.Lancet. 2019; 394: 1145-1158Summary Full Text Full Text PDF PubMed Scopus (2427) Google Scholar intriguing. However, we have some concerns. Our major concern arises from mixing data from mainland China and Taiwan. These two regions have distinct health-care and social welfare systems; they also have different time trends of how socioeconomic conditions evolved during the past half century. Therefore, mixing the data from these two regions might lead to biased estimates, especially for the health outcomes shaped by health policies (eg, vaccination programmes as a prevention strategy). Among all health issues, mental health is a particularly heterogeneous area between Taiwan and China. For example, the increasing suicide rate in Taiwan peaked in 2005,2Fu TST Lee CS Gunnell D Lee WC Cheng ATA Changing trends in the prevalence of common mental disorders in Taiwan: a 20-year repeated cross-sectional survey.Lancet. 2013; 381: 235-241Summary Full Text Full Text PDF PubMed Scopus (106) Google Scholar whereas the suicide rate started to decline in China as early as 1990. Furthermore, the demographic risk factors associated with some mental health issues have been found to differ substantially between China and most developed countries, such as Taiwan. For example, the male-to-female ratio of alcoholism was 33:1 in China,3Tang YL Xiang XJ Wang XY Cubells JF Babor TF Hao W Alcohol and alcohol-related harm in China: policy changes needed.Bull World Health Organ. 2013; 91: 270-276Crossref PubMed Scopus (127) Google Scholar whereas the corresponding ratio was 8:5 in Taiwan.4Cheng WJ Cheng Y Huang MC Chen CJ Alcohol dependence, consumption of alcoholic energy drinks and associated work characteristics in the Taiwan working population.Alcohol Alcohol. 2012; 47: 372-379Crossref PubMed Scopus (52) Google Scholar Sex and alcoholism could jointly influence the susceptibility to several health outcomes, and therefore the difference in the sex ratio for alcoholism might lead to different disease burden estimates. Mixing such data from these two regions might therefore cause misinterpretations in associations between risk factors and outcomes due to ecological fallacy. This error might also complicate the assessment of an emerging disease, such as COVID-19. We believe that these concerns are worthy of being addressed. We declare no competing interests. Methodology in the GBD study of ChinaMaigeng Zhou and colleagues1 claimed that they had implemented the same hierarchical model setup as Christopher Murray and colleagues had in their Global Burden of Disease Study (GBD),2 in which Taiwan and China were treated at the same level in the hierarchical model. However, according to figures 3 and 4 in the Article,1 Taiwan was placed at the level under the umbrella of China. The inconsistency between the methodology and results in these figures requires clarification. Full-Text PDF Methodology in the GBD study of China – Author's replyThe Global Burden of Disease Study (GBD) 2017 provides comprehensive assessment of population health for 195 countries and territories and subnational units for selected countries, including all province-level administrative units in China. It is important to point out that, as the GBD uses a hierarchical analytical framework, data input from all GBD 2017 analytical units, national or subnational, are integrated into a single modelling process to provide a set of estimates for all locations that are internally consistent and comparable across locations and over time. Full-Text PDF