The temporal trends of prevalence and years lived with disability of anaemia in China, Japan, and South Korea, from 1990 to 2021: Results from the Global Burden of Disease Study 2021.

Background: Studies have shown that the disease burden of anaemia varies globally, yet they have not yet determined its exact extent in East Asian countries specifically. We thus aimed to investigate the prevalence and years lived with disability (YLDs) due to anaemia from 1990 to 2021 in China, Japan, and South Korea. Methods: We extracted the prevalence and YLDs with their age-standardised rates (ASRs) in China, Japan, and South Korea from the Global Burden of Disease Study 2021, stratified by sex, age, and causes. We then examined the temporal trend of anaemia burden from 1990 to 2021 using joinpoint analysis and the association of anaemia burden with the Human Development Index and Universal Health Index through Spearman's correlation analysis. Results: In 2021, anaemia affected 136 million people in China (95% uncertainty interval (UI) = 131, 141), with ASRs of prevalence of 8.9% (95% UI = 8.6, 9.3), and accounted for 3.0 million YLDs (95% UI = 2.0, 4.4). It affected 13.6 million people in Japan (95% UI = 11.8, 16.0), with ASRs of prevalence of 7.4% (95% UI = 6.1, 9.0), and caused 181 thousand YLDs (95% UI = 108, 282). It also affected 2.7 million individuals in South Korea (95% UI = 2.4, 3.0), with ASRs of prevalence of 5.2% (95% UI = 4.6, 5.7), and led to 34 thousand YLDs (95% UI = 22, 55). We observed a significant gender discrepancy in the anaemia burden in these three countries, with the prevalence and YLD rates in women being almost twice as high as those in men. Moreover, the peak age of the anaemia burden shifted toward higher age groups in all three countries, particularly in Japan. Chronic kidney disease was responsible for a growing share of anaemia cases and YLDs, especially in adults aged more than 60 years in Japan and South Korea. Haemoglobinopathies were another noticeable cause of anaemia in China, though dietary iron deficiency remained the leading cause. Both socioeconomic development and essential health service coverage showed negative associations with the anaemia burden in the three countries in the past three decades, though with differential patterns. Conclusions: Anaemia remains a major public health issue in China, Japan, and South Korea; targeted surveillance and interventions are recommended for high-risk populations and cause-specific anaemia.