To date, there has been no national-level epidemiological survey of skin diseases and their burden in China. Using data from the 2019 Global Burden of Disease (GBD 2019) and China’s 2010 national census as the standard population, this study estimated age-standardized incidence, prevalence, mortality, and burden of skin disease in 1990 and 2019. In 2019, there were an estimated 5,393 deaths, 369,127,390 cases of skin diseases, 8,264,702 person-years of disability adjusted life years (DALYs) lost, 8,167,678 person-years of years living with disability (YLDs), and 97,024 person-years of years of life lost (YLLs) caused by skin diseases. In 2019, the age group of 15–49 years had the most number of cases of skin disease, DALYs and YLDs, whereas people over 70 years had the highest incidence, prevalence, and mortality for skin disease. DALYs steadily increased between 1990 and 2019, while DALYs rate declined. The ranking of DALYs by skin disease varied by age group, indicating that the specific disease burdens varied by age.
The GBD provided estimates of incidence, prevalence, mortality, YLLs, YLDs, and DALYs lost due to 369 diseases or injuries in 204 countries and territories (1). GBD divided skin and subcutaneous tissue diseases into 12 categories: 1) dermatitis; 2) psoriasis; 3) scabies; 4) fungal skin diseases; 5) viral skin diseases; 6) acne vulgaris; 7) alopecia areata; 8) pruritus; 9) urticaria; 10) decubitus ulcers; 11) bacterial skin diseases; and 12) other skin and subcutaneous diseases (1-2). In China, skin disease data were obtained from epidemiological surveillance, disease registries, scientific literature, and other surveys such as the China National Health Services Survey 2008. Information from Chinese data sources can be found online at the Global Health Data Exchange website (3).
Specific mortality data were available for 6 skin and subcutaneous diseases using the Cause of Death Ensemble model (CODEm) and spatiotemporal Gaussian process regression, aimed to predict best age-specific and sex-specific mortality estimates by etiology, while considering temporal and spatial trends with the use of predictive covariates, age of death and age-specific standard life expectancy data were used to determine YLLs (1-2). A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to calculate the prevalence of each skin disease using historical data on incidence, prevalence, remission, mortality, and disease duration. Prevalence estimates were multiplied by disability weights to calculate YLDs by specific cause (4). From GBD, sex-specific indicators of incidence, prevalence, mortality, and burden of skin diseases were obtained for 1990 and 2019 and were expressed in numbers (cases) and rates (per 100,000 population). Age-standardized rates of these indicators were calculated using the 2010 population in the national census as the standard population. Percent change (%) was calculated by dividing the difference between 2019 and 1990 values by the 1990 value and multiplying by one hundred. Statistical analyses were performed with SAS (version 9.4, SAS Research Institute, Inc., Cary, USA).
Table 1 shows that standardized skin disease DALYs and YLDs were stable in China between 1990 and 2019, while YLLs rate decreased significantly. DALYs rate and YLDs rate of females were slightly higher than that of males.
Groups Incidence Prevalence Deaths DALYs YLLs YLDs Number of cases Rate* (1/100,000) Number of cases Rate* (1/100,000) Number of cases Rate* (1/100,000) Number of person-years Rate* (1/100,000) Number of person-years Rate* (1/100,000) Number of person-years Rate* (1/100,000) Males 1990 311,782,134 53,257.99 142,257,295 23,376.97 3,238 0.92 3,455,241 554.89 128,804 23.67 3,326,437 531.22 2019 395,228,276 53,753.19 177,940,599 24,623.91 2,613 0.33 3,910,417 545.94 55,039 6.96 3,855,379 538.97 Increase (%) 26.76 0.93 25.08 5.33 −19.31 −64.31 13.17 −1.61 −57.27 −70.59 15.90 1.46 Females 1990 294,727,431 53,089.72 147,866,780 25,892.05 3142 0.78 3,747,176 634.60 98,168 18.08 3,649,008 616.52 2019 389,166,985 53,803.06 191,186,791 27,337.99 2,780 0.27 4,354,285 641.26 41,986 4.59 4,312,299 636.67 Increase (%) 32.04 1.34 29.30 5.58 −11.52 −65.86 16.20 1.05 −57.23 −74.60 18.18 3.27 Total 1990 606,509,566 53,166.61 290,124,075 24,598.30 6,380 0.85 7,202,417 593.54 226,972 20.90 6,975,445 572.64 2019 784,395,261 53,776.32 369,127,390 25,951.95 5,393 0.30 8,264,702 592.08 97,024 5.77 8,167,678 586.31 Increase (%) 29.33 1.15 27.23 5.50 −15.47 −65.03 14.75 −0.25 −57.25 −72.41 17.09 2.39 Abbreviations: DALYs=disability-adjusted life years; YLLs=years of life lost; YLDs=years lived with disability.
*: Standardized rates were calculated using the 2010 national census as the standard population, expressed as 1/100,000. The percentage change (%) was calculated as the difference between 2019 and 1990 divided by the amount in 1990.
Table 1. Incidence, prevalence, death, disease burden and changes of skin diseases by sex in China, 1990 and 2019.
Supplementary Table S1 shows that in 2019, DALYs and YLDs due to skin disease were highest among people aged 15–49 years, while rates of DALYs and YLDs were highest in the 5–14 age group. People over 70 years ranked first among all age groups on YLLs and YLLs rate. Compared with 1990, DALYs and YLDs increased in age groups over 15 years. However, YLLs due to skin disease decreased in all age groups except for the people aged over 70 by years old 2019, and DALYs rate decreased in all age groups except for the 5–14 age group.
In Figure 1, it showed that there was an increase for DALYs and YLDs of skin disease in China from 1990 to 2019, while the rates of DALYs and YLDs decreased slowly. Compared with males, females had higher numbers of DALYs and YLDs, and higher rates of DALYs and YLDs of skin disease.
Figure 1. DALYs and YLDs by sex for skin disease in China, 1990–2019. (A) DALYs by sex for skin disease in China, 1990–2019; (B) DALY rate by sex for skin disease in China, 1990–2019; (C) YLDs by sex for skin disease in China, 1990–2019; (D) YLD rate by sex for skin disease in China, 1990−2019. Abbreviations: DALYs=disability-adjusted life years; YLDs=years lived with disability.
Supplementary Table S2 indicated that for DALYs and rate of DALYs, viral skin diseases was the largest contributor among people under 15 years compared with other age groups. Dermatitis contributed the highest number of DALYs and the highest DALY rate among people over 15 years old. As for the ranking of the skin disease burden, acne vulgaris increased significantly in people aged 5–14 years, while in the groups aged over 50 years or above, fungal skin disease and scabies showed a rapid increase.