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National and provincial disease burden of childhood asthma in China, 2010–2021: A systematic analysis of the Global Burden of Disease Study 2021

Year: 2025

Type: article

Abstract: To the Editor: Asthma ranks among the 10 leading causes of non-fatal disease burden in Chinese children.[1] Although the prevalence of childhood asthma is relatively low, compared with that in 204 countries and territories worldwide,[1] the number of children affected is considerable, given China’s large population size. Driven by differential exposure to environmental and lifestyle risk factors, the prevalence of asthma differed substantially across regions.[2] Childhood asthma often persists in adulthood.[3] Therefore, understanding the current trends and prevalence of childhood asthma is critical for anticipating the future disease burden. However, no national surveys focusing on childhood asthma have been conducted since 2013. We leveraged Global Burden of Disease and Risk Factors Study (GBD) 2021 data to examine the prevalence, incidence, mortality, and disability-adjusted life years (DALYs) associated with asthma in children aged 0–14 years, from 2010 to 2021. By analyzing temporal and geographical changes in childhood asthma, we aimed to highlight disparities and health care gaps, providing evidence to support reforms and improve asthma management across China. The GBD 2021 provides systematic estimations of incidence, prevalence, mortality, and morbidity for 371 diseases and injuries in 204 countries and territories. In addition to national estimates, the subnational burden is reported for 21 countries and territories, including China. Asthma is characterized by reversible airway obstruction due to spasms and secretions in the bronchi, typically resulting from an allergic reaction or hypersensitivity, and causing difficulty in breathing. In GBD 2021, asthma was determined according to a doctor’s diagnosis and wheezing in the previous year. The corresponding International Classification of Diseases (Tenth Revision) codes are J45 and J46. In addition, four non-standard case definitions were considered and standardized.[1] Detailed information on data collection and processing, as well as the modeling strategy for the GBD 2021, has been previously published [Supplementary Table 1, https://links.lww.com/CM9/C698].[1] The prevalence and incidence of asthma were modeled using DisMod-MR 2.1, a Bayesian meta-regression tool designed for disease modeling. Two covariates were included in the model: log-lagged distributed income and the asthma summary exposure variable, a scalar variable combining exposure to all GBD risks influencing asthma. Deaths associated with asthma were modeled using the Cause of Death Ensemble model.[1] Herein, we focused on counts and rates of prevalence, incidence, mortality, and DALYs related to childhood asthma in China, as well as across its 31 provinces (autonomous regions, municipalities) and two special administration regions (Hong Kong and Macao) from 2010 to 2021. We set the age limit to 14 years and examined estimates based on three 5-year age groups. In addition to the prevalence and overall disease burden, we examined the DALY rate attributable to two specific risk factors—high body-mass index (BMI) and nitrogen dioxide (NO2) pollution—analyzed by year, sex, age, and location. All statistical analyses were performed using R, version 4.3.3 (The R Project for Statistical Computing, Vienna, Austria). In 2021, an estimated 9.37 (95% uncertainty interval [UI]: 6.41–14.03) million prevalent cases of childhood asthma were recorded in China, with a prevalence of 3.61% (2.47%–5.40%) [Supplementary Table 2, https://links.lww.com/CM9/C698]. Boys had a higher prevalence than girls, with cases in boys comprising 60.0% of total childhood asthma cases. The highest number of cases, 4.23 (2.71–6.81) million, occurred in children aged 5–9 years, with a prevalence rate of 4.41% (2.83%–7.11%). Compared with 2010, the number of prevalent cases and the crude prevalence rate at the national level increased by 27.64% (17.96%–39.25%) and 8.98% (0.72%–18.90%), respectively [Figure 1A and Supplementary Table 2, https://links.lww.com/CM9/C698]. Across provinces, the highest number of childhood asthma cases was observed in Henan with 0.90 (0.62–1.34) million, whereas the lowest was in Macao with 3.77 (2.59–5.61) thousand. High age-standardized prevalence was mostly observed in eastern and coastal regions, whereas lower prevalence was observed in parts of southwestern and northern China [Supplementary Table 3, https://links.lww.com/CM9/C698].Figure 1: Trend of prevalent cases (A), incident cases (B), deaths (C), and DALYs (D) and corresponding crude rates of childhood asthma in China, 2010–2021. The shaded area indicates 95% uncertainty intervals. DALYs: Disability-adjusted life years.In 2021, 2.26 (1.50–3.44) million new childhood asthma cases were recorded in China, with a crude incidence rate of 0.87% (0.58%–1.32%). Similar to prevalence, there were more boys in new patients, while more new cases occurred in the age group <5 years [Figure 1B and Supplementary Table 4, https://links.lww.com/CM9/C698]. The highest age-standardized incidence was recorded in Hong Kong [Supplementary Table 3, https://links.lww.com/CM9/C698]. In 2021, the total number of deaths associated with childhood asthma was estimated at 68 (50–96), with 41 (29–59) deaths in boys and 27 (17–48) in girls. This represents a 66.38% (52.13%–75.08%) decline in deaths since 2010. The crude death rate decreased by 71.29% (59.13%–78.72%), from 0.09 (0.08–0.12) per 100,000 to 0.03 (0.02–0.04) per 100,000 [Figure 1C and Supplementary Table 5, https://links.lww.com/CM9/C698]. Most provinces recorded fewer than one death associated with childhood asthma [Supplementary Table 3, https://links.lww.com/CM9/C698]. The highest age-standardized death rate was observed in Xizang, estimated at 0.09 per 100,000. In 2021, 0.39 (0.22–0.67) million DALYs were attributable to childhood asthma in China, with a crude DALY rate of 149.42 (83.23–257.60) per 100,000. The total number of DALYs was higher among boys at 0.23 (0.13–0.41) million, with a DALY rate of 167.95 (92.73–293.16) per 100,000. During 2010–2021, DALYs and crude DALY rates increased by 22.62% (13.16%–33.05%) and 4.69% (–3.38%–13.60%), respectively [Figure 1D and Supplementary Table 6, https://links.lww.com/CM9/C698]. Across provinces, the highest number of DALYs attributable to childhood asthma in 2021 was observed in Henan at 36,947 (20,336–64,281), whereas the lowest was recorded in Macao at 155 (83–266). For age-standardized DALY rates, the highest estimate of 165.48 per 100,000 was observed in Hong Kong, whereas the lowest rate of 122.45 per 100,000 was in Heilongjiang [Supplementary Table 3, https://links.lww.com/CM9/C698]. Supplementary Figure 1, https://links.lww.com/CM9/C698 shows the spatial distribution of the percentage of DALYs attributable to high BMI and NO2 pollution across China. At the national level, 7.65% (3.85%–11.78%) of total DALYs were attributable to a high BMI, whereas 4.74% (–4.20%–19.77%) of asthma-related DALYs were attributable to NO2 pollution. The contributions of each risk factor differed by province. The proportion of asthma-related DALYs attributed to high BMI was highest in Tianjin at 12.65% (6.49%–19.54%), and lowest in Xizang at 2.47% (1.16%–4.27%). The highest proportion of DALYs attributable to NO2 pollution was observed in Shanghai at 20.38% (–24.49%–56.71%). Similar patterns were observed when considering DALY rates, as shown in Supplementary Figure 2, https://links.lww.com/CM9/C698. This is the comprehensive analysis of the prevalence, incidence, mortality, and DALYs of childhood asthma in China at both national and subnational levels from 2010 to 2021. Our results indicated that asthma remains a serious public health issue among children in China. Childhood asthma accounted for more than one-third of all-age asthma cases and 26.44% of all-age asthma-related DALYs.[1] The asthma prevalence and DALYs were higher among boys than girls, generally peaking in children aged 5–9 years; these findings may be related to physiological differences and variations in behavioral patterns by sex and age. We observed considerable geographical disparities, with higher prevalence and DALY rates in some eastern and coastal areas, and lower rates in parts of the southwestern and northern regions. Owing to diverse environmental and social factors across provinces in China, it is essential to tailor asthma prevention and control strategies to match local conditions. Despite the overall burden of childhood asthma having increased over the past decade, the death rate has declined substantially. This may be owing to the advancement of medical technology and disease management, which has led to more patients being diagnosed and surviving for extended periods. However, this may also reflect a shift in the disease burden from mortality to long-term morbidity, thereby increasing health care utilization and costs. Based on available evidence between risk factors and outcomes, the GBD framework assessed the contribution of high BMI and NO2 pollution to childhood asthma. High BMI is a key factor in the childhood asthma burden of China, accounting for an estimated 7.65% of total DALYs. Particularly in northern regions, the prevalence of childhood overweight and obesity is high and continues to rise.[4] These trends in obesity parallel the patterns of childhood asthma. Preventing further increases in childhood asthma will require scaling up the management of childhood obesity. NO2 exposure is another critical risk factor for childhood asthma. Provincial variations in the childhood asthma prevalence and DALYs are closely associated with the spatial distribution of NO2 concentrations and exposure. Over the past 10 years, multiple national and local emission control policies have yielded some success in NO2 reduction.[5] However, a significant decline in childhood asthma is yet to be observed. Hence, controlling the use of fuels and reducing industrial emission are public health priorities to avoid further increases in childhood asthma.[6] This study provides the comprehensive analysis of childhood asthma prevalence, incidence, mortality, and disease burden in China at both national and subnational levels during 2010–2021. Childhood asthma remains a serious public health challenge, with high prevalence, incidence, and DALY rate in eastern and coastal regions. Key risk factors, including high BMI and NO2 pollution, continue to drive the burden. To help curtail growth of the childhood asthma burden, comprehensive management strategies should be implemented, tailored to the varying risk factors in different regions. Acknowledgments We sincerely thank the support from health experts in the Institute for Health Metrics and Evaluation and appreciate the contributions of all GBD 2021 collaborators. Funding This study was supported by the Natural Science Foundation of Beijing (No. 7252178), the National Natural Science Foundation of China (No. 82103797) and the Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology, China (No. BYESS2023385). This research has been conducted as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), coordinated by the Institute for Health Metrics and Evaluation. The GBD was partially funded by the Bill & Melinda Gates Foundation; the funders had no role in the study design, data analysis, data interpretation, or writing of the report. Conflicts of interest None.

Source: Chinese Medical Journal

DOI: 10.1097/cm9.0000000000003910