Disease burden of AIDS in last 30-year period and its predicted level in next 25-years based on the global burden disease 2019

Abstract

Background

This study examines global trends in acquired immune deficiency syndrome (AIDS) incidence, mortality, and disability-adjusted life years (DALYs) from 1990 to 2019, focusing on regional disparities in AIDS incidence, mortality, and DALYs across various levels of socio-demographic index (SDI). It also investigates variations in AIDS incidence, mortality, and DALYs across different age groups, and projects specific trends for the next 25 years.

Methods

Comprehensive data on AIDS from 1990 to 2019 in 204 countries and territories was obtained from a GBD study. This included information on AIDS incidence, mortality, DALYs, and age-standardized rates (ASRs). Projections for AIDS incidence and mortality over the next 25 years were generated using the Bayesian age-period-cohort model.

Results

From 1990 to 2019, the global incidence of HIV cases increased from 1,989,282 to 2,057,710, while the age-standardized incidence rate (ASIR) decreased from 37.59 to 25.24 with an estimated annual percentage change (EAPC) of -2.38. The ASIR exhibited an upward trend in high SDI and high-middle SDI regions, a stable trend in middle SDI regions, and a downward trend in low-middle SDI and low SDI regions. In regions with higher SDI, the ASIR was higher in males than in females, while the opposite was observed in lower SDI regions. Throughout 1990 to 2019, the age-standardized death rate (ASDR) and age-standardized DALY rate remained stable, with EAPCs of 0.24 and 0.08 respectively. Countries with the highest HIV burden affecting women and children under five years of age are primarily situated in lower SDI regions, particularly in sub-Saharan Africa. Projections indicate a significant continued decline in the age-standardized incidence and mortality rates of AIDS over the next 25 years, for both overall and by gender.

Conclusions

The global ASIR decreased from 1990 to 2019. Higher incidence and death rates were observed in the lower SDI region, indicating a greater susceptibility to AIDS among women and < 15 years old. This underscores the urgent need for increased resources to combat AIDS in this region, with focused attention on protecting women and < 15 years old as priority groups. The AIDS epidemic remained severe in sub-Saharan Africa. Projections for the next 25 years indicate a substantial and ongoing decline in both age-standardized incidence and mortality rates.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-024-19934-4.

Background

In 2020, there were 680,000 acquired immune deficiency syndrome (AIDS)-related deaths [1]. AIDS was the 11th leading cause of disability adjusted life years (DALYs) among all ages, and it was the second leading cause of DALY in the age group of 25 to 49 years [2]. Notably, the AIDS epidemic was particularly severe in sub-Saharan Africa [3].

Since its discovery in 1981, AIDS has garnered significant attention, leading to substantial investment and policy initiatives aimed at addressing this formidable threat. For instance, the Millennium Development Goals established in 2000 included the Millennium Development Goal 6, which had two specific targets related to AIDS: ensuring universal access to AIDS treatment by 2010, and halting and starting to reverse the spread of AIDS by 2015. This framework contributed to mobilizing over US$500 billion for global AIDS care, prevention, and treatment between 2000 and 2015 [4, 5]. Another significant initiative was the US President's Emergency Plan for AIDS Relief, which allocated substantial funds and assistance to sub-Saharan Africa [6]. The Joint United Nations Programme on HIV and AIDS had set the 90–90-90 target to achieve by 2020, which aimed for 90% of people living with HIV to be aware of their status, 90% of those aware to receive treatment, and 90% of those receiving treatment to have a suppressed viral load. However, the program only achieved 84–87-90 by the target date. The Sustainable Development Goals, introduced in 2015 to guide global development efforts from 2015 to 2030, included the ambitious objective of ending the AIDS epidemic by 2030 [7].

The objective of this study was to analyze the worldwide percentage of change in AIDS incidence, mortality, and DALYs, as well as the variations in these measures across different levels of socio-demographic index (SDI) and age groups for 1990 and 2019. Additionally, we aim to forecast the 25-year trend in age-standardized incidence and mortality rates of AIDS categorized by gender.

Methods

Data sources

The annual incidence, mortality, DALYs, and age-standardized rates (ASRs) of AIDS between 1990 and 2019 were sourced from the Global Health Data Exchange query tool (http://ghdx.healthdata.org/gbd-results-tool).

Data processing

The data collected on June 20, 2023 were stratified by sex and age to evaluate the impact of age and gender on the burden of AIDS. For a broader investigation of global AIDS trends, we categorized geographic information based on three criteria. Firstly, the data were examined at the level of 204 countries and territories. Subsequently, global data were disaggregated into 21 GBD regions to assess geographical variations. Additionally, we classified countries, territories, and regions into five categories (High, High-middle, Middle, Low-middle, Low) based on the SDI (Supplementary Table 1). The SDI represents the average years of education among individuals aged 15 and above, per capita income, and total fertility, ranging from 0 to 1 [8, 9].

Statistical analysis

ASRs and estimated annual percentage changes (EAPCs) are valuable for quantifying AIDS incidence and mortality trends. Meanwhile, DALYs represent the combined years of life lost and years lived with disability, encompassing both fatal and nonfatal burdens [9]. When comparing several populations with different age structures or when the age structures of the same population changed over time, in order to eliminate the effect of the different age composition of the population, the comparability of statistical indicators is guaranteed, age standardization was adopted. The ASRs (per 100,000 population) can be calculated by the following formula: ASR = $\frac{{\sum }_{i=1}^A{a}_i{w}_i}{{\sum }_{i=1}^A{w}_i}\times 100,000$, ($a_i$ represents the rate of ith age class and represented the number of persons in the same age subgroup i of the chosen reference standard population) [10]. The EAPC can show the trend of ASR over a selected period of time. y = α + βx + ɛ, where y = ln(ASR), and x = calendar year. The EAPC = 100 × (exp(β)-1). $EAPC=\left(\frac{{\widehat{\mathit{ASR}}}_{x+1}-{\widehat{\mathit{ASR}}}_x}{{\widehat{\mathit{ASR}}}_x}\right)·100=\left(\frac{{\widehat{\mathit{ASR}}}_{x+1}}{{\widehat{\mathit{ASR}}}_x},-,1\right)·100=\left(\frac{e^{\widehat{y}+\widehat{\beta }}\left(x,+,1\right)}{e^{\widehat{y}+\widehat{\beta }}·x},-,1\right)·100=\left(e,x,p,\left(\beta \right),-,1\right)\times 100$, where y represents ln (ASR), and x is expressed as the calendar year. We obtained the ASR directly from the database, so plugging x into the first formula can calculate β. Then, the EAPC was calculated by substituting β into the second simplified formula. From the regression model, we can also obtain its 95% confidential interval (CI) [11]. If the EAPC and its lower limit of 95%CI were both > 0, the ASR was in an increasing trend. However, if the EAPC and its upper limit of 95%CI were both < 0, the ASR was in a decreasing trend. Otherwise, ASR was in a stable trend over time.

Pearson analyses were utilized to investigate the relationships between ASRs and the SDI, as well as between the ratio of incidence cases in female subjects to male subjects and the SDI. The two variables exhibit a complete positive correlation when the correlation coefficient equals 1, and a complete negative correlation when the correlation coefficient equals -1 [12]. To project age-standardized HIV incidence and mortality rates for 2020–2044, age-period-cohort (APC) analyses were conducted by sex using the Nordpred package in R, taking into account rates of change. Additionally, sensitivity analyses were executed employing the Bayesian age-period-cohort model and the Nested Laplace Approximation packages. The stability of the predictions was confirmed through the Bayesian age-period-cohort model combined with the Nested Laplace Approximation in R [13]. When the p-value of all results was less than 0.05, statistical significance was determined. The statistical analyses were conducted using R software (Version 4.1.0).

Results

Incidence burden of AIDS

In 2019, the global incidence of AIDS was 1,989,282 (95%UI, 1,760,907–2,259,348), and it remained relatively stable compared to 2,057,710 (95%UI, 1,708,166–2,430,844) in 1990. Conversely, the age-standardized incidence rate (ASIR) experienced a noteworthy decline from 37.59 (95%UI, 31.12–44.54) in 1990 to 25.24 (95%UI, 22.39–28.57) in 2019, with an EAPC of -2.38 (95%CI, -2.82 to -1.93) over the past 30 years, indicating a global diminishing trend in ASIR (Table 1).The percentage of cases in individuals aged < 15 displayed a unimodal distribution from 1990 to 2019, peaking at 15.45% in 2004. Throughout 1990 to 2019, the two age groups with the highest incidence of cases were 15 to 29 and 30 to 44 on a global scale, with the 15 to 39 age group exhibiting the highest incidence rate in most countries and territories (Supplementary Fig. 1A and Supplementary Table 2). Subsequent analysis revealed that in both 1990 and 2019, the highest incidence rate for females occurred in the 25 to 29 age group, while for males, it was in the 30 to 34 age group, with a unimodal distribution evident from 15 to 79 years for both genders (Fig. 1A&B).

Table 1.

The incident cases and ASIR of AIDS in 1990 and 2019

	1990		2019		1990–2019 EAPC No.(95%CI)
	Incident cases No.*102(95%UI)	ASIR per 100,000 No.(95%UI)	Incident cases No.*102(95%UI)	ASIR per 100,000 No.(95%UI)
Overall	20,577.10(17,081.66–24,308.44)	37.59(31.12–44.54)	19,892.82(17,609.07–22593.48)	25.24(22.39–28.57)	-2.38(-2.82 to -1.93)
Sex
Female	11,378.90(9165.13–13,710.08)	41.34(33.17–49.96)	9985.85(8618.40–11653.58)	25.74(22.29–30.00)	-2.66(-3.13 to -2.19)
Male	9198.20(7805.44–10,636.65)	33.98(28.62–39.46)	9906.97(8777.31–11,102.87)	24.82(22.02–27.84)	-2.06(-2.48 to -1.63)
Socio-demographic index
High SDI	798.90(543.33–1076.32)	9.11(6.14–12.35)	940.33(504.14–1377.54)	9.32(5.10–13.43)	0.70(0.27–1.14)
High-middle SDI	705.08(569.22–895.89)	5.68(4.59–7.19)	2317.39(1970.55–2787.30)	15.13(13.00–18.30)	2.62(1.86–3.39)
Middle SDI	2352.39(1990.78–2735.51)	13.47(11.49–15.64)	6509.10(5729.43–7467.42)	25.84(22.80–29.35)	0.18(-1.03–1.41)
Low-middle SDI	6180.22(4609.39–7904.60)	57.71(42.91–74.28)	4314.82(3571.56–5245.43)	23.68(19.52–28.90)	-4.41(-4.89 to -3.92)
Low SDI	10,517.51(7988.42–13,304.28)	224.59(168.30–286.76)	5076.23(3870.47–6706.91)	47.96(36.36–63.13)	-5.35(-5.5 to -5.20)
Region
Andean Latin America	23.95(15.84–48.33)	6.22(4.11–13.25)	113.22(82.23–172.03)	17.09(12.57–25.92)	3.18(2.61–3.75)
Australasia	11.89(9.86–13.84)	5.52(4.61–6.42)	16.40(9.86–23.91)	5.75(3.38–8.47)	0.20(-0.28–0.67)
Caribbean	404.34(276.63–583.22)	113.72(77.24–166.76)	175.40(120.05–251.70)	36.14(24.76–51.80)	-3.57(-3.84 to -3.30)
Central Asia	13.87(8.97–20.77)	1.96(1.30–2.94)	73.89(50.95–98.59)	7.16(4.95–9.50)	4.52(3.92–5.13)
Central Europe	8.95(6.04–12.64)	0.74(0.49–1.05)	19.91(15.75–27.26)	1.91(1.50–2.64)	2.03(1.27–2.79)
Central Latin America	233.67(164.70–321.07)	14.94(10.88–20.16)	397.17(329.41–497.59)	15.08(12.61–18.74)	1.03(0.59–1.46)
Central Sub-Saharan Africa	1339.95(967.89–1750.90)	279.88(202.47–366.62)	815.72(550.06–1169.18)	70.12(46.73–100.97)	-4.60(-4.83 to -4.36)
East Asia	101.66(65.48–184.60)	0.81(0.52–1.56)	343.67(161.51–555.80)	2.3(1.18–3.80)	3.04(1.34–4.78)
Eastern Europe	115.20(90.95–144.33)	4.92(3.77–6.26)	1556.26(1257.22–1954.04)	71.58(58.95–89.74)	10.35(9.38–11.32)
Eastern Sub-Saharan Africa	10,729.25(8640.87–12,939.45)	655.15(520.28–799.30)	5066.59(3846.24–6606.30)	132.72(100.76–175.17)	-5.72(-5.91 to -5.53)
High-income Asia Pacific	18.25(10.04–31.01)	0.97(0.53–1.65)	45.69(25.18–67.86)	2.15(1.29–3.11)	2.54(1.85–3.23)
High-income North America	618.43(385.55–866.79)	20.31(12.70–28.60)	704.71(307.82–1091.22)	19.78(8.85–30.13)	0.64(0.04–1.24)
North Africa and Middle East	39.76(14.08–96.36)	1.27(0.44–3.10)	241.38(98.18–636.07)	3.74(1.53–9.63)	2.62(2.11–3.14)
Oceania	1.65(0.40–4.80)	2.78(0.64–8.57)	75.94(2.18–249.99)	58.21(1.64–191.70)	5.96(2.66–9.37)
South Asia	286.05(114.58–588.46)	2.83(1.21–5.63)	879.10(500.77–1650.38)	4.66(2.63–8.55)	-3.45(-5.58 to -1.27)
Southeast Asia	899.60(593.97–1235.01)	19.68(13.14–27.17)	1267.77(1074.59–1659.16)	18.11(15.18–23.93)	-1.04(-1.52 to -0.57)
Southern Latin America	63.68(43.39–86.69)	12.74(8.72–17.32)	165.74(89.96–263.02)	24.75(13.09–39.63)	2.12(1.97–2.27)
Southern Sub-Saharan Africa	2312.09(1107.49–3700.59)	460.33(220.10–740.72)	4415.20(3517.33–5495.76)	528.2(420.92–658.50)	-1.83(-3.09 to -0.56)
Tropical Latin America	270.77(220.39–320.21)	16.81(13.93–19.59)	660.79(513.88–805.04)	27.34(21.47–33.42)	1.88(1.36–2.40)
Western Europe	282.24(229.84–398.91)	7.14(5.82–10.13)	250.65(186.65–319.92)	6.18(4.49–7.94)	0.07(-0.46–0.60)
Western Sub-Saharan Africa	2801.84(1845.20–4052.15)	169.9(112.43–247.05)	2607.61(2140.25–3246.21)	65.3(53.31–81.71)	-4.64(-5.13 to -4.15)

ASIR Age-standardized incidence rate, EAPC Estimated annual percentage change, SDI Socio-demographic index, UI Uncertainty interval; CI, confidence interval

* stands for multiplication sign

Fig. 1.

The incidence, death, and DALY rates of AIDS in different age groups globally. Note: A Incidence rate in 1990. B Incidence rate in 2019. C Death rate in 1990. D Death rate in 2019. E DALY rate in 1990. F DALY rate in 2019

In 2019, ASIR across the five SDI regions ranked as follows: low SDI region, middle SDI region, low-middle SDI region, high-middle SDI region, and high SDI region. Over the period from 1990 to 2019, the low SDI region experienced the most substantial decline in ASIR among the five SDI regions, followed by the low-middle SDI region. The ASIR in the middle SDI region exhibited a stable trend, while both the high SDI region and the high-middle SDI region showed an upward trend (Table 1, Fig. 2 and 3A).Pearson analysis revealed a non-significant negative correlation between ASIR and SDI across 204 different countries and territories (ρ = − 0.32 for 1990; ρ = − 0.26 for 2000; ρ = − 0.27 for 2010; ρ = − 0.23 for 2019; All P < 0.01) (Figs. 3D& 4A). In 2019, a higher SDI corresponded to a lower proportion of incidence cases among individuals aged < 15 (Fig. 5B) within the five SDI regions. The ASIR for males in the high SDI and high-middle SDI regions surpassed that of females, whereas in the middle SDI, low-middle SDI, and low SDI regions, the opposite was observed (Supplementary Fig. 2D).

Fig. 2.

The change trends of age-standardized incidence, death, and DALY rate among different SDI quintiles. Note: A, B, C: Age-standardized incidence rate in both females and males, females, males. D, E, F: age-standardized death rate in both females and males, females, males. G, H, I: age-standardized DALY rate in both females and males, females, males

Fig. 3.

The EAPC of AIDS in global and different regions. Note: A The EAPCs in ASIR. B The EAPCs in ASDR. C The EAPCs in age-standardized DALY rate

Fig. 4.

The correlation between SDI and ASR, death, and DALY. Note: The circles represent the different 204 countries and territories that were available from GBD. The size of the circle indicates the number of people living with AIDS in that country and territories. The ρ is Pearson’s correlation coefficient and p values were derived from Pearson’s correlation analysis

Fig. 5.

Distribution of different ages in AIDS incidence/death cases and DALYs. Note: A Incidence cases in 1990. B Incidence cases in 2019. C Death cases in 1990. D Death cases in 2019. E DALYs in 1990. F DALYs in 2019

Across various age groups, the 15 to 19-year age bracket consistently demonstrated the highest ratio of female to male incidence rates across SDI regions. Additionally, the ratio of female to male incidence rates in the age groups of 15 to 19, 20 to 24, and 25 to 29 years increased as regional SDI decreased (Supplementary Fig. 3). Figure 6 demonstrated a significant negative correlation between the ratio of female incident cases aged 15 to 29 years and male incident cases aged 15 to 29 years and the SDI of the respective country. Pearson's coefficient remained relatively constant from 1990 to 2019 (ρ = − 0.65 for 1990; ρ = − 0.60 for 2000; ρ = − 0.64 for 2010; ρ = − 0.64 for 2019; P < 0.01 for all years).

Fig. 6.

Correlation between feamle/male aged 15 to 29 years old and SDI. Note: The red dots represent the different countries and territories. The ρ is Pearson’s correlation coefficient and p values were derived from Pearson’s correlation analysis

In 1990, sub-Saharan Africa and the Caribbean topped the list of regions with the highest ASIR, whereas in 2019, sub-Saharan Africa, Eastern Europe, Oceania, and the Caribbean held this distinction. Conversely, Central Europe, high-income Asia Pacific, and East Asia recorded the lowest ASIR in 2019 (Supplementary Fig. 2A&D). Analysis of Supplementary Table 3, Supplementary Table 4, and Supplementary Fig. 4 revealed that in 2019, the 20 countries with the highest ASIR were all located in sub-Saharan Africa. Lesotho, Mozambique, and Equatorial Guinea were the three countries with the highest ASIR, while the three countries with the lowest ASIR were Albania, Qatar, and the Syrian Arab Republic. The proportion of elderly incidence cases increased in most regions in 2019 compared to 1990, with high proportions observed in the high-income Asia Pacific (43.47), East Asia (17.11), and high SDI (8.16) regions (Fig. 5A&B). The global decline in AIDS ASIR was mainly driven by the downward trend in sub-Saharan Africa, the Caribbean, Southeast Asia, and South Asia. Conversely, the ASIR of other regions depicted an upward or stable trend, with Eastern Europe, Oceania, and Central Asia exhibiting the most significant upward trend (Fig. 3). Additionally, Armenia, Georgia, and Estonia had the highest EAPC, while Burundi, Ethiopia, and Cambodia had the lowest EAPC (Fig. 7A, Supplementary Table 3 and Supplementary Table 4).

Fig. 7.

The global EAPC of AIDS for both females and males. Note: A The EAPC in ASIR. B The EAPC in ASDR. C The EAPC in age-standardized DALY rate

Death and DALY burden of AIDS

On a global scale, the age-standardized death rate (ASDR) and age-standardized DALY rate exhibited an upward trend from 1990 to 2004 followed by a decrease from 2005 to 2019. The EAPC for ASDR was 0.24 (95% CI, -1.43 to 1.94), while the EAPC for the age-standardized DALY rate was 0.08 (95% CI, -1.55 to 1.74) during the period from 1990 to 2019 (Tables 2 and 3, and Fig. 2D&G).In 2019, the ASDR and age-standardized DALY rate were nearly identical for males and females worldwide (Supplementary Fig. 2E&F).In 2019, both the global DALY rate and death rate exhibited a unimodal distribution across the age spectrum from 5 to 95 + years for both females and males.In 2019, the highest mortality rate occurred in the 40–44 age group for both males and females, and the peak DALY rate was observed at 35 to 39 years for females and 40 to 44 years for males (Fig. 1D&F).As indicated in Supplementary Table 5 and Supplementary Table 6, the majority of countries and territories displayed a unimodal distribution of mortality rates and DALY rates across the age range from 5 to 95 + years.Between 1990 and 2019, the ratio of deaths and DALYs among individuals under 15 years and those in the 15–29 age bracket decreased, while there was an increase among those aged 30–44, 45–59, and 60 + years. These changes were especially notable for individuals under 15 years and those aged 45–59 (Supplementary Fig. 1B&C).Nonetheless, the percentage of deaths and DALYs among individuals under 15 years of age remained elevated in Andean Latin America, eastern sub-Saharan Africa, and the low SDI region, with a negative correlation observed between SDI levels and the proportion of deaths among < 15-year-olds (Fig. 5D&F).

Table 2.

The death cases and ASDR of AIDS in 1990 and 2019

	1990		2019		1990–2019 EAPC No.(95%CI)
	Death cases No.*102(95%UI)	ASDR per 100,000 No.(95%UI)	Death cases No.*102(95%UI)	ASDR per 100,000 No.(95%UI)
Overall	3363.87(2556.83–4521.94)	6.38(4.81–8.62)	8638.37(7860.75–9960.45)	10.72(9.70–12.39)	0.24(-1.43–1.94)
Sex
Female	1652.62(1205.28–2296.52)	6.22(4.48–8.67)	4284.43(3829.09–5016.82)	10.72(9.51–12.61)	0.24(-1.6–2.11)
Male	1711.25(1351.55–2205.88)	6.54(5.13–8.50)	4353.94(3988.08–4998.66)	10.74(9.81–12.40)	0.26(-1.23–1.76)
Socio-demographic index
High SDI	359.80(357.42–362.29)	3.97(3.94–4.00)	106.26(101.20–117.49)	0.84(0.80–0.96)	-6.89(-7.7 to -6.06)
High-middle SDI	175.34(169.53–184.88)	1.47(1.42–1.55)	508.05(491.09–531.39)	3.04(2.93–3.20)	1.24(0.06–2.43)
Middle SDI	171.80(139.58–219.14)	1.04(0.83–1.34)	2780.34(2522.72–3257.75)	10.53(9.53–12.40)	5.93(3.09–8.86)
Low-middle SDI	606.09(418.77–916.98)	5.59(3.72–8.74)	2557.88(2286.73–2950.39)	14.93(13.52–17.01)	0.88(-1.27–3.08)
Low SDI	2047.62(1444.55–2856.85)	45.25(30.54–64.98)	2678.00(2333.13–3240.54)	30.11(27.06–35.09)	-2.86(-4.39 to -1.31)
Region
Andean Latin America	7.72(5.57–15.30)	2.31(1.62–4.70)	43.40(28.16–82.65)	6.77(4.38–12.97)	3.62(2.7–4.54)
Australasia	4.30(4.20–4.42)	1.95(1.91–2.01)	0.79(0.77–0.82)	0.23(0.23–0.24)	-8.86(-9.85 to -7.87)
Caribbean	50.82(35.84–80.10)	15.01(10.69–23.25)	93.74(78.89–114.52)	19.03(15.97–23.32)	-1.30(-2.75–0.18)
Central Asia	3.27(3.13–3.40)	0.54(0.51–0.56)	12.75(12.29–13.25)	1.28(1.23–1.33)	2.37(1.33–3.41)
Central Europe	4.72(4.33–4.99)	0.4(0.37–0.42)	4.47(4.24–5.02)	0.35(0.34–0.39)	-1.99(-3.09 to -0.89)
Central Latin America	38.50(38.10–38.91)	2.8(2.77–2.83)	120.22(114.57–125.17)	4.66(4.43–4.85)	0.99(0.27–1.72)
Central Sub-Saharan Africa	239.82(162.78–349.74)	52.59(35.09–78.01)	400.94(328.21–505.10)	40.9(34.54–49.44)	-2.17(-3.45 to -0.88)
East Asia	27.37(7.34–39.83)	0.24(0.07–0.34)	326.78(261.06–396.50)	1.74(1.40–2.09)	5.98(5.37–6.59)
Eastern Europe	50.81(50.22–51.36)	2.15(2.13–2.17)	259.94(256.35–263.50)	10.94(10.80–11.09)	5.99(5.24–6.74)
Eastern Sub-Saharan Africa	1877.01(1341.36–2607.37)	119.85(80.37–172.33)	2463.85(2177.05–2932.43)	80.12(73.44–90.78)
High-income Asia Pacific	1.29(1.26–1.32)	0.07(0.07–0.07)	3.40(3.30–3.51)	0.13(0.13–0.14)	2.17(1.42–2.92)
High-income North America	285.92(283.56–288.31)	9.11(9.03–9.18)	73.08(72.25–73.89)	1.64(1.62–1.66)	-7.52(-8.31 to -6.72)
North Africa and Middle East	7.19(3.34–16.28)	0.24(0.11–0.55)	94.33(55.06–185.55)	1.51(0.88–3.04)	5.69(4.47–6.93)
Oceania	0.21(0.09–0.68)	0.31(0.11–1.06)	41.75(13.48–113.12)	35.61(12.45–96.39)	16.51(12.39–20.78)
South Asia	14.31(8.92–27.02)	0.12(0.06–0.26)	520.70(421.76–825.36)	2.89(2.35–4.64)	8.51(3.77–13.46)
Southeast Asia	22.45(18.39–29.21)	0.49(0.39–0.67)	429.51(358.61–544.16)	6(4.96–7.70)	4.62(1.79–7.53)
Southern Latin America	7.11(7.00–7.21)	1.48(1.46–1.50)	24.46(24.06–24.87)	3.35(3.29–3.40)	0.99(-0.1–2.10)
Southern Sub-Saharan Africa	168.50(87.44–334.64)	33.61(17.46–68.92)	1880.72(1642.60–2270.46)	247.28(220.41–291.71)	4.34(1.31–7.47)
Tropical Latin America	81.06(79.69–82.36)	5.54(5.45–5.62)	161.31(157.84–165.05)	6.47(6.32–6.62)	-0.88(-1.43 to -0.32)
Western Europe	101.19(100.15–102.27)	2.46(2.44–2.49)	32.18(31.65–32.80)	0.6(0.59–0.61)	-7.09(-8.02 to -6.16)
Western Sub-Saharan Africa	370.29(241.34–597.77)	22.87(14.72–37.49)	1650.03(1389.77–1989.94)	50.66(44.70–58.94)	0.63(-1.2–2.49)

ASDR Age-standardized death rate, EAPC Estimated annual percentage change, SDI Socio-demographic index, UI Uncertainty interval, CI Confidence interval

* stands for multiplication sign

Table 3.

The DALY and age-standardized DALY rate of AIDS in 1990 and 2019

	1990		2019		1990–2019 EAPC No.(95%CI)
	DALY No.*103(95%UI)	Age-standardized DALY Rate per 100,000 No.(95%UI)	DALY No.*103(95%UI)	Age-standardized DALY Rate per 100,000 No.(95%UI)
Overall	20,915.85(16,525.43–27,291.85)	379.58(296.69–499.56)	47,632.18(42,630.99–55,650.04)	601.49(536.16–703.92)	0.08(-1.55–1.74)
Sex
Female	10,576.89(7998.63–14,252.87)	382.96(287.70–519.76)	24,286.40(28,616.85–21,357.67)	620.75(543.97–733.98)	0.08(-1.69–1.88)
Male	10,338.95(8409.66–13,098.86)	376.22(303.35–477.41)	23,345.78(27,140.35–21,108.90)	583.34(525.67–679.55)	0.09(-1.38–1.58)
Socio-demographic index
High SDI	1915.00(1858.59–1987.77)	213.7(207.53–221.73)	620.84(521.80–747.41)	51.78(43.65–62.36)	-6.43(-7.28 to -5.59)
High-middle SDI	999.44(964.76–1052.39)	83.24(80.29–87.86)	2752.78(2618.34–2938.58)	172.44(163.60–184.18)	1.19(0.02–2.37)
Middle SDI	1106.45(942.46–1348.93)	62.84(52.90–77.69)	14,714.40(13,273.53–17,332.75)	568.7(510.39–672.63)	5.59(2.82–8.43)
Low-middle SDI	3998.00(2885.37–5771.80)	336.16(235.36502.83)	13,950.23(12,220.88–16,341.38)	795.43(703.30–921.08)	0.60(-1.47–2.71)
Low SDI	12,877.09(9534.04–17312.23)	2501.89(1762.13–3511.47)	15,551.58(13,229.66–18,952.91)	1578.46(1387.12–1877.83)	-2.98(-4.44 to -1.49)
Region
Andean Latin America	47.23(35.49–89.98)	127.79(93.61–253.97)	259.66(163.34–492.51)	400.96(251.36–762.66)	4.02(3.13–4.91)
Australasia	22.08(21.30–22.94)	100.26(96.71–104.12)	4.89(4.16–5.91)	14.8(12.71–17.84)	-8.10(-9.15 to -7.04)
Caribbean	305.86(211.92–484.24)	860.36(602.64–1359.01)	484.66(403.46–602.61)	1002.14(828.70–1249.77)	-1.44(-2.86–0.00)
Central Asia	18.69(17.96–19.38)	29.21(28.09–30.31)	71.15(67.78–74.76)	70.86(67.48–74.47)	2.43(1.41–3.46)
Central Europe	28.31(25.91–29.92)	26.01(23.87–27.47)	24.40(22.48–28.33)	21.11(19.48–23.99)	-2.51(-3.74 to -1.27)
Central Latin America	216.18(212.70–220.12)	144.37(142.13–146.85)	632.11(605.35–661.07)	244(233.50–255.72)	1.01(0.28–1.74)
Central Sub-Saharan Africa	1484.17(1022.17–2121.91)	2832.8(1912.07–4160.84)	2221.93(1777.11–2839.56)	2050.21(1695.81–2546.25)	-2.34(-3.56 to -1.09)
East Asia	158.45(54.12–219.98)	12.95(4.50–17.97)	1441.75(1136.94–1811.66)	82.37(65.91–102.64)	5.66(5.1–6.23)
Eastern Europe	275.24(268.88–285.50)	119.99(117.32–124.13)	1453.87(1399.24–1525.79)	630.46(606.93–661.93)	6.15(5.41–6.89)
Eastern Sub-Saharan Africa	11,966.04(8965.87–16,072.46)	6585.85(4635.43–9198.11)	14,398.36(12,394.14–17,302.74)	4141.16(3732.24–4808.22)	-3.29(-4.85 to -1.71)
High-income Asia Pacific	6.73(6.13–7.43)	3.74(3.43–4.11)	20.15(15.98–25.93)	8.82(7.29–10.97)	2.79(2.15–3.42)
High-income North America	1532.15(1483.20–1595.12)	487.94(472.43–507.80)	433.18(362.15–530.23)	102(85.78–123.58)	-7.02(-7.84 to -6.20)
North Africa and Middle East	46.20(22.29–108.91)	13.48(6.54–29.64)	509.13(292.58–1024.99)	79.29(45.26–160.62)	5.49(4.28–6.71)
Oceania	1.53(0.78–4.67)	20.06(8.96–65.33)	221.64(62.17–607.02)	1775.74(535.12–4894.80)	15.76(11.75–19.91)
South Asia	116.74(82.67–191.82)	8.79(5.74–15.58)	2927.12(2331.73–4676.77)	160.06(128.20–254.57)	7.67(3.2–12.32)
Southeast Asia	158.81(139.25–188.78)	32.47(27.94–39.95)	2392.33(2057.90–2957.69)	336.51(288.05–419.04)	4.27(1.66–6.95)
Southern Latin America	39.81(37.86–42.20)	82.1(78.15–87.03)	138.08(123.61–162.50)	192.41(171.92–226.98)	0.99(-0.11–2.10)
Southern Sub-Saharan Africa	1145.03(586.55–2206.82)	2089.37(1097.06–4074.81)	10,110.57(8689.81–12,327.66)	12,776.7(11,185.64–15,298.06)	3.81(0.91–6.79)
Tropical Latin America	486.69(474.43–500.57)	317.63(309.75–326.95)	840.17(802.38–885.86)	342.53(326.79–361.83)	-1.15(-1.69 to -0.60)
Western Europe	548.98(536.17–562.74)	137.1(133.96–140.46)	185.94(163.52–215.29)	36.76(32.62–42.35)	-6.83(-7.77 to -5.89)
Western Sub-Saharan Africa	2310.94(1545.40–3678.24)	1259.76(832.04–2042.92)	8861.10(7347.94–10,890.25)	2460.72(2128.06–2914.02)	0.28(-1.5–2.09)

DALY Disability adjusted life-year, EAPC Estimated annual percentage change, SDI Socio-demographic index, UI Uncertainty interval, CI Confidence interval

* stands for multiplication sign

Since 1997, within the five SDI regions, there was a negative correlation between SDI and the ASDR as well as the age-standardized DALY rate (Fig. 2D&G).During the period from 1990 to 2019, the ASDR and age-standardized DALY rate exhibited a declining pattern in high SDI and low SDI regions, an ascending trend in high-middle and middle SDI regions, and a stable trend in the low-middle SDI region (Fig. 3B&C).Within the low SDI and low-middle SDI regions, the ASDR and age-standardized DALY rate for females exceeded those for males, whereas the reverse was observed in the middle SDI, high-middle SDI, and high SDI regions (Supplementary Fig. 2E&F).Pearson analysis revealed a non-significant negative correlation between ASDR and SDI, as well as between age-standardized DALY rate and SDI, as shown in Fig. 4E&L.

Sub-Saharan Africa, Oceania, the Caribbean, and Eastern Europe had the highest ASDR and age-standardized DALY rate (Supplementary Fig. 2B&C).In 2019, Lesotho, Eswatini, and Mozambique exhibited the highest ASDR and age-standardized DALY rates, while the lowest ASDRs were observed in Bosnia and Herzegovina, Albania, and Kuwait, and the lowest age-standardized DALY rates were noted in Bosnia and Herzegovina, Albania, and Egypt.Oceania, South Asia, and Eastern Europe experienced the most significant increase in ASDR and age-standardized DALY rate, while Australasia, High-income North America, and Western Europe showed the most substantial decrease in ASDR and age-standardized DALY rate.Nepal, Lao People's Democratic Republic, and Bangladesh showed the highest estimated EAPC in ASDR, whereas France, Australia, and Burkina Faso had the lowest EAPC in ASDR. For the age-standardized DALY rates, the countries with the fastest growth were Nepal, Lao People's Democratic Republic, and Bangladesh, while the most rapid decline was observed in France, Burkina Faso, and Spain (Figs. 3B&C and 7B&C, Supplementary Table 4, Supplementary Table 7, and Supplementary Table 8).

Predictions level of age-standardized incidence and mortality rate for AIDS

According to our predictions across genders, we observed consistent trends. In the male group, there was a smoother change in the first three decades, followed by a 15-year decline (Fig. 8A). For females, we predict a decline in overall incidence rate over the next 25 years, approaching a similar level (Fig. 8B). Globally, we observed a rapid increase in age-standardized AIDS incidence rate since 1990, peaking in 1997 and then following a similar declining trend, with a slight slowdown around 2005, reaching its lowest level in 2019. The overall trend resembled a "hump" shape (Fig. 8C). It is evident that from 2020 to 2044, the age-standardized incidence rate is anticipated to continue declining, albeit at a slower rate than before 2019. The prediction intervals for age-standardized mortality rates had greater width for males than for any other predicted value, but the overall downward trend exhibited little difference (Fig. 8D). Conversely, for females, the projected decline over the next 25 years remains relatively consistent (Fig. 8E). On a global scale, an overall "inverted V" shape was observed in the projections of age-standardized mortality rates over the next 25 years. Using 2004 as the dividing line, the left and right sides exhibited essentially symmetrical but opposite trends. Similar to age-standardized incidence rates, age-standardized mortality rates are anticipated to decline over the next 25 years, although with a gentler slope and wider projection intervals (Fig. 8F).

Fig. 8.

The projections of global AIDS age-standardized incidence and mortality rates from 2020 to 2044 using Bayesian APC models. Note: Global age-standardized projections of HIV incidence (A, B, C) and mortality (D, E, F). Fan charts show the distribution of predictions between the 5% and 95% interquartiles, with shaded bands showing the prediction intervals in terms of. Predicted mean values are shown as solid lines. The vertical dashed line indicates where the prediction begins

The AIDS burden of women and children

Among the 204 countries analyzed, the three with the highest ASIR for women are Lesotho (1,018.53), Equatorial Guinea (793.69), and Mozambique (748.99). The countries with the highest ASDR for women are Lesotho (591.69), Eswatini (317.32), and Mozambique (279.21). Furthermore, Lesotho (30,501.26), Eswatini (17,532.49), and Mozambique (15,767.17) exhibit the highest age-standardized DALY rate ratios for females, all significantly exceeding the global average (Supplementary Table 4). Regarding children under five years old, the highest ASIR are observed in Lesotho (441.50), Mozambique (415.97), and Swaziland (387.05). The highest ASDR for this age group are recorded in Mozambique (189.28), Lesotho (159.87), and Swaziland (113.43). Additionally, the countries with the highest age-standardized DALY rate for children under five years old are Mozambique (16,657.37), Lesotho (14,111.54), and Swaziland (10,012.70) (Supplementary Table 2, Supplementary Table 5 and Supplementary Table 6). All of these countries are classified in low SDI regions, predominantly within sub-Saharan Africa.

Discussion

This study comprehensively examined the incidence, mortality, and DALYs of AIDS from 1990 to 2019, considering factors such as SDI, gender, age, countries, territories, and regions. The primary objective was to provide insights that can contribute to the strategy for eradicating AIDS by 2030.

The study revealed that in lower SDI regions, the ASIR, ASDR, and age-standardized DALY rate were higher for females than for males. Conversely, in higher SDI regions, the ASIR, ASDR, and age-standardized DALY rate were higher for males than for females. Furthermore, the ratio of incidence cases in females to those in males between the ages of 15 and 29 exhibited a strong negative correlation with the SDI of the respective country. These findings indicate varying gender-related AIDS issues across different development regions. Among the 204 countries and territories worldwide, the highest HIV burden among women and children under five years of age is concentrated in lower SDI regions, primarily in sub-Saharan Africa. This indicates that women and children in sub-Saharan Africa require increased assistance. Furthermore, women and children in these regions are at a higher risk of AIDS compared to their counterparts in other parts of the world, necessitating greater investment in resources and more effective measures to mitigate their risk. Over the period of 1981 to 2011, men who have sex with men (MSM) constituted the group most affected by AIDS in high-income countries, such as the United States, where approximately half of all cases occurred in MSM [14]. Furthermore, the incidence of AIDS among MSM continued to rise in certain high-income countries [15]. Multiple factors have contributed to the HIV epidemic among MSM. In both low- and high-income countries, there has been a surge in MSM using the internet to seek sexual partners, thus amplifying the risk of HIV transmission. Simultaneously, stigma, discrimination, and violence stemming from the criminalization of same-sex sexual behavior have impeded the availability, accessibility, and utilization of HIV prevention, testing, treatment, and care services [15, 16]. In countries experiencing an epidemic, such as Lebanon, the provision of comprehensive HIV and STI services for men who have sex with men and other key populations fosters an enabling environment for individuals living with AIDS to access treatment and prevention services [17]. This approach has significantly contributed to reducing HIV incidence among these key populations and their sexual partners.

In Eastern and Southern Africa, girls and women are typically infected with HIV 5 to 7 years earlier than boys and men [18]. In sub-Saharan Africa, females aged 15 to 24 account for approximately 25% of all new HIV infections, despite representing only 10% of the population [18].

In sub-Saharan Africa, adolescent girls and young women are three times more likely to contract HIV than their male counterparts of the same age group, and the rate of new infections is declining more slowly among women due to various factors, including policy and legal barriers to accessing HIV services, discriminatory laws and practices, social discrimination, difficulties in accessing services, the absence of a dedicated budget to address women's HIV-related needs, and limited educational and economic opportunities for women [19, 20]. Adolescent girls and young women face a heightened risk of experiencing rape and engaging in the sex trade to meet their daily needs, while also being exposed to sexual and gender-based violence, gender-based exclusion, and exploitation, frequently leading to early or unwanted pregnancies [21–23]. Even 200 million women and girls in developing countries who wish to avoid pregnancy lack access to modern contraception [24]. Evidence from heavily affected African countries demonstrates that keeping girls in secondary school can halve their risk of contracting HIV [25]. Compared to adolescent girls and women, pregnant women receive more comprehensive HIV care. Since 2000, high-income countries have successfully reduced mother-to-child transmission rates to less than 1–2% through the use of antiretroviral therapy for pregnant women. In low- and middle-income countries, coverage of antiretroviral treatment during pregnancy increased from 50% in 2010 to 75% in 2016, resulting in a 47% decline in new HIV infections among children [26].

The proportion of new cases among < 15 years old reached its peak at 15.45% in 2004 and has steadily decreased each year to 6.41% in 2019. The percentage of < 15 years old deaths decreased from 22.63% in 1990 to 8.85% in 2019. Similarly, the proportion of disability-adjusted life years decreased from 31.81% in 1990 to 13.9% in 2019, signifying significant progress in treating AIDS in < 15 years old. Nonetheless, with the decline in SDI, the proportions of AIDS incidence, deaths, and disability-adjusted life years in < 15 years old have increased. In 2017, approximately 3 million children were living with HIV globally, with 87% of these cases occurring in sub-Saharan Africa. Among children under 19 years of age, there were 430,000 new HIV infections, 41% of which occurred in children under 5 years, primarily due to mother-to-child transmission [18]. Therefore, it is critical to continue efforts to ensure that pregnant women have access to services aimed at preventing transmission.

New cases of HIV among < 15 years old had been virtually eliminated in high-income countries, shifting the focus to low- and middle-income countries, especially in sub-Saharan Africa, where the majority of pediatric AIDS cases occurred [27]. The Start Free, Stay Free, AIDS Free initiative targeted 23 countries, 21 of which were in sub-Saharan Africa, with the aim of reducing HIV transmission among < 15 years old. Other recommended strategies for preventing and managing HIV in < 15 years old include: heightened political and financial commitment; implementation of a couples-based approach; expanded HIV testing for females before, during, and after pregnancy; recognition of adolescent girls and young women as high-risk groups, leading to enhanced protection and treatment; and integration of maternal and child health services with HIV interventions [28, 29].

The proportion of deaths and DALYs declined among younger individuals but rose among older individuals, mirroring the increased average lifespan of AIDS patients. However, the improved life expectancy of AIDS patients also implies a greater number of elderly patients, necessitating increased attention to the health status and quality of life of older individuals. In response to the increasing effectiveness of HIV antiretroviral therapy and the rising life expectancy of individuals living with HIV, the prevalence of older adults living with HIV is projected to rise, reaching 70 percent of those aged 50 years or older living with HIV by 2030. Since 2009, the annual International Symposium on AIDS and Aging has encouraged researchers to develop treatments and clinical care specifically for older individuals living with HIV [30].

A study revealed that elderly individuals with HIV, in comparison to HIV-negative Medicare beneficiaries, faced elevated risks of experiencing multiple chronic conditions and increased mortality rates [31].

The proportion of new AIDS cases among the elderly in high SDI regions reached as high as 8.16%. Notably, the highest proportions of new cases among the elderly were observed in high-income Asia Pacific (43.47%) and East Asia (17.11%). A study conducted in China revealed that individuals aged 50 and above, particularly males, led solitary and monotonous spiritual lives, potentially harboring more complex and diverse sexual needs than younger individuals. Moreover, they exhibited limited knowledge about AIDS, engaged in commercial or high-risk sexual behaviors, and faced a heightened risk of HIV infection [32].

The study unveiled a global downward trend in the ASIR of AIDS. This decline, however, exhibited non-uniform patterns, with decreases observed solely in sub-Saharan Africa, the Caribbean, Southeast Asia, and South Asia. In contrast, other regions demonstrated stable or increasing trends, with Eastern Europe, Oceania, and Central Asia registering the fastest ASIR growth. Unlike the worldwide epidemic, a majority of AIDS patients in Eastern Europe and Central Asia were users of illicit drugs, highlighting evidence of a correlation between injecting drug use and HIV transmission through high-risk sexual behavior [33]. In Eastern Europe and Central Asia, only 63% of individuals living with AIDS were aware of their status, and among those aware, merely 45% received antiretroviral therapy, with only 22% achieving AIDS suppression. Given this context, implementing harm reduction strategies is essential in the fight against AIDS, encompassing comprehensive coverage of syringe service programs and opioid agonist therapies like methadone and buprenorphine maintenance therapy [34]. These measures should be integrated with effective AIDS responses that enhance HIV testing accessibility and utilize combination antiretroviral therapy for both treatment and prevention [34]. The primary issue in Oceania centered on Papua New Guinea, home to the region's largest population and the most severe AIDS situation, accounting for 19 out of the 20 reported AIDS cases in the Pacific from 1984 to 2007 [35].

The most heavily impacted region was sub-Saharan Africa, which has been the primary focus of concern. AIDS prevention and management in this region relied significantly on health development aid, with 63.9% of AIDS spending in 2015 being sourced from such assistance [36].This underscored the vulnerability of the epidemic in this location. A global, regional, and national burden study of AIDS could offer valuable insights to aid policymakers in making informed decisions tailored to the distinct circumstances in combating AIDS.

Both the ASIR and ASDR are anticipated to diminish slightly from 2020 to 2044 in comparison to the preceding 30 years, with a more pronounced decrease in ASIR. However, no significant disparity between genders was observed. This trend may be linked to increased global focus and research investment in HIV pathogenesis, treatment strategies, and prevention [24].The combination of highly active antiretroviral therapy and other treatments has significantly decreased the morbidity and mortality associated with HIV infection [16, 33, 37]. The relatively modest decline in ASIR may be related to sexual behaviour [38], AIDS knowledge, age, income, and high-risk drug use [39], and male homosexuality [40]. However, the upper limit of the prediction interval for ASDR in males was considerably higher than that in other groups, suggesting that males may have a higher ASDR in the future. This possibility may be associated with the lower viral load and stronger antiviral response in females compared to males during the acute infection period following HIV infection, consequently leading to differences in viral reservoir size [41]. Thus, additional investment is required for AIDS prevention and treatment measures to effectively reduce the global disease burden of AIDS.

This study was conducted based on the GBD study. While it utilized high-quality estimates of AIDS, it also encountered some unavoidable limitations. Primarily, the GBD study divided basic data units into countries and territories without including race information, thus overlooking the racial factor in HIV. Analyzing and comparing global trends and variations in HIV incidence, mortality, DALYs, and changes in these metrics across different levels of SDI and age groups within each racial group poses a challenge.For countries, racial differences should be considered in HIV testing, prevention, treatment and decision-making [42]. Secondly, early data or data from countries and territories with low levels of development may not be accurate. Additionally, the study lacked direct data on aspects such as ART and the prevention of mother-to-child HIV transmission, which could have improved the analysis of the epidemic trend of AIDS. Moreover, the lengthy 25-year time span is susceptible to various uncontrollable factors, potentially impacting the predicted results of age-standardized incidence rate and mortality.

Conclusions

The following is a paragraph from an academic paper. Refinish writing to conform to academic style, improve spelling, grammar, clarity, conciseness, and overall readability. If necessary, rewrite the entire sentence. In addition, list all modifications in the Markdown table and explain the reasons for doing so.The ASIR showed a declining trend from 1990 to 2019 globally, the incidence rate of < 15 years old and the proportion of incidence cases among < 15 years old drastically decreased, and there was an increase in the life expectancy of people living with AIDS. However, the declining trend in ASIR was uneven, and the regions with the downward trend included only sub-Saharan Africa, the Caribbean, Southeast Asia, and South Asia; while ASIR significantly increased in Eastern Europe, Oceania, and Central Asia. To prevent further AIDS epidemics, sufficient attention should be given to these regions where the incidence of AIDS was increasing. The incidence rate and death rate were higher in the lower SDI region, and the female and < 15 years old living here had a greater risk of HIV infection, which suggest that more resources are needed to fight AIDS in the region and that female and < 15 years old should be considered priority groups here. The AIDS epidemic remained serious in sub-Saharan Africa, which had the highest ASIR, ASDR and age-standardized DALY rate, indicating that global concern still needed to be concentrated here. The projections for the 25-year period from 2020 to 2044 showed that the age-standardized incidence rate and mortality rate would still maintain a significant downward trend, but the decline in age-standardized mortality rate was more gradual than that in age-standardized incidence rate. This suggested that health departments and hospitals at all levels still cannot relax their attention to AIDS treatment and prognosis. However, this is not absolute, and more data and research were needed to further explore. Furthermore, the prevention and control of AIDS still need to be strengthened.

Abbreviations

AIDS

Acquired immune deficiency syndrome

ASIR

Age-standardized incidence rate

ASDR

Age-standardized death rate

CI

Confidence interval

DALY

Disability-adjusted life year

EAPC

Estimated annual percentage change

GBD

Global Burden of Disease

HIV

Human immunodeficiency virus

MSM

Male who had sex with male

SDI

Socio-Demographic Index

Authors’ contributions

Study concept and design: Chao Zhang and Xiao-Long Wang. Acquisition of data: Teng-Yu Gao, Lin-Kang Zhao and Hao-Yang Li. Data analysis and interpretation: Lin-Kang Zhao, Teng-Yu Gao, Xiao-Long Wang, Hao-Yang Li, Yu-Tong Ma and Wei Fang. Drafting the manuscript: Chao Zhang and Teng-Yu Gao. Critical revision of manuscript: All authors. All authors had full access to all the data in the study and had final responsibility for the decisions to submit for publication.

Funding

None.

Availability of data and materials

To download the data used in these analyses, please visit the Global Health Data Exchange GBD 2019 data-input sources tool at http://ghdx.healthdata.org/gbd-2019/data-input-sources. No permission is required for anyone to access this data.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.