Overview of the global burden

Between 1990 and 2021, the incidence of OM in children increased from 256 million to 297 million, representing a 15.97% rise. The ASIR saw a marginal increase from 14,737.24 to 14,774.55 per 100,000 population, with an EAPC of 0.12 (95% CI: 0.08–0.17). While the number of DALYs rose from 0.97 million to 1.04 million during this period, the age-standardized DALY rate (ASDR) decreased from 55.74 to 51.48 per 100,000 population, showing an EAPC of -0.19 (95% CI: -0.23 to -0.15) (Tables 1, Table S1).

Table 1 Global burden and incidence of OM in children from 1990 to 2021 by sex and age, and the incidence in five SDI regionsSex specific trends

In 1990, the incidence of OM in females was 129 million, with an ASIR of 15,226.11 per 100,000. By 2021, this figure had increased to 147 million cases with an ASIR of 15,157.9 per 100,000, showing an EAPC of 0.1 (95% CI: 0.06–0.14). For males, the 1990 incidence was 127 million cases with an ASIR of 14,274.55 per 100,000, which rose to 149 million cases and an ASIR of 14,415 per 100,000 by 2021. Males exhibited a marginally higher EAPC of 0.15 (95% CI: 0.11– 0.19) compared to females (Table 1; Fig. 1A and B). Notably, the ASDR for both sexes decreased over time, with fluctuating trends observed: a decrease from 1990 to 1998, an increase from 1998 to 2012, and another decrease from 2012 to 2021 (Table 1, Table S1).

Fig. 1

Trends in the global burden of Otitis Media (OM) in children from 1990 to 2021, presented by sex, age group, and SDI region. (A) Age-Standardized Incidence Rate (ASIR) and Age-Standardized DALYs Rate (ASDR) trends by sex; (B) Number of incidence cases and Disability-Adjusted Life Years (DALYs) cases trends by sex; (C) ASIR and ASDR trends by age group; (D) Number of incidence cases and DALYs cases trends by age group; (E) ASIR and ASDR trends by Socio-Demographic Index (SDI) region; (F) Number of incidence cases and DALYs cases trends by SDI region

Age-specific trends

The ASIR was highest in children aged < 1 year (27,495.37 per 100,000) and declined with increasing age, reaching 5,127.74 per 100,000 in the 10–14 years age group. The peak number of cases (98 million) occurred in the 2–4 years age group. The EAPCs for the < 1 year, 2–4 years, 5–9 years, and 10–14 years age groups were 0.08, 0.14, 0.18, and 0.13, respectively. Despite an increase in the number of cases and ASIR across these age groups, the ASDR for each group showed a downward trend, with the most substantial decrease seen in children aged < 1 year (Table 1, Table S1, Fig. 1C and D, Fig.S1A-1B).

SDI at the regional level

Between 1990 and 2021, the ASIR of OM varied significantly across different SDI regions (Table 1, Table S1, Fig. 1E and F, Fig.S1C-1D). The lowest ASIR was observed in the high- and high-middle-SDI regions, at 11,834.62 and 11,792.11, respectively, with both showing a downward trend in case numbers. In contrast, the highest ASIR were found in the low- and low-middle-SDI regions, at 18,354.62 and 17,371.69, respectively. These regions experienced a significant increase in cases, particularly in the low-SDI region, where cases nearly doubled, rising from 42 million (95% UI: 29–60) to 79 million (95% UI: 54–114). The EAPC exhibited a decline in both the low-SDI (-0.18; 95% CI: -0.21 to -0.16) and low-middle-SDI regions (-0.15; 95% CI: -0.16 to -0.13). In the middle-SDI region, the ASIR showed a fluctuating pattern but decreased overall from 1990 to 2021. Notably, between 2019 and 2021, both case numbers and ASIR decreased in all SDI regions except the low-SDI region, likely due to the impact of the COVID-19 pandemic. By 2021, the ASDR in low-SDI regions (59.69) was nearly double that in high-SDI regions (32.14). Although ASDR declined across all regions, the most significant decrease was seen in low-SDI regions, with an EAPC of -0.68.

GBD region and country level

From 1990 to 2021, most regions and countries demonstrated either stable or declining trends (Fig.S2-S3, Table S2). Eastern Europe and high-income Asia-Pacific regions, however, showed significant increases in EAPC, with rates of 0.29 and 0.22, respectively. In contrast, regions such as Western and Central Sub-Saharan Africa, as well as Central Latin America, showed notable declines in EAPC, with rates of -0.16, -0.14, and − 0.16, respectively. The highest ASIR was recorded in Eastern Sub-Saharan Africa (17,880.67), while the lowest was in Central Europe (9,827.73). Despite an overall increase in the EAPC of ASIR, the EAPC of DALYs decreased across all 21 regions, with the most significant declines occurring in Central Sub-Saharan Africa (-1.33) and Central Europe (-0.99).

In GBD regions, the burden of OM in children varies widely. To identify regions with similar changes in burden, this study used hierarchical clustering analysis. Notably, the ASIR and ASDR in Central Europe showed significant increases, while both metrics decreased significantly in Eastern Sub-Saharan Africa (Fig.S3).

At the national level, the Northern Mariana Islands, American Samoa, and Syrian Arab Republic displayed the largest declines in EAPC, with rates of -0.7, -0.57, and − 0.55, respectively. Conversely, South Korea, Algeria, and Russia experienced the largest increases in EAPC, with rates of 0.43, 0.37, and 0.33, respectively. Ethiopia recorded the highest ASIR, at 18,687.09, while Taiwan (China) reported the lowest, at 7,300.39. Overall, the burden of OM in children has decreased across various countries and regions (Table S3, Fig. 2).

Fig. 2

The burden of Otitis Media (OM) in children across countries and regions worldwide in 2021 and trends from 1990 to 2021. (A) ASIR of OM in children in 2021; (B) EAPC for the ASIR in 2021. (C) ASDR of OM in children in 2021; (D) EAPC for the ASDR in 2021; (E) Number of OM cases worldwide in 2021; (F) Number of OM DALYs worldwide in 2021

Correlation analysis

The relationship between ASIR and the SDI is U-shaped: ASIR decreases as SDI increases from 0 − 0.75 but rises when SDI ranges from 0.75 to 1.0 (Fig. 3). There is a negative correlation between the ASR and EAPC (P < 0.01, ρ = -0.20), while the HDI positively correlates with EAPC (P < 0.01, ρ = 0.35). The ASDR decreases as SDI decreases. No significant relationship was observed between ASDR and HDI (P = 0.11, ρ = -0.11), or between ASDR and EAPC (P = 0.66, ρ = 0.04) (Fig. 4).

Fig. 3

Relationship between the ASR and SDI in children with OM. (A, B) ASIR and SDI; (C, D) ASDR and SDI

Fig. 4

Relationship between EAPC, ASR, and HDI in children with OM in 2021. (A) EAPC and ASR; (B) EAPC and HDI. The size of the spots represents different numbers of cases

Frontier analysis of 204 countries and regions

Frontier analysis of ASIR of OM from 1990 to 2021 revealed significant heterogeneity in prevention and control across different countries and regions. Fifteen countries, including Spain, Pakistan, South Africa, Sweden, Kenya showed significantly higher rates, positioning them far from the frontier. Conversely, low-SDI countries/regions such as Niger, Somalia and Timor-Leste were closer to the frontier, indicating more effective disease control relative to their SDI levels. In contrast, nations with high SDI such as Sweden, Norway and the United Kingdom demonstrated greater distances from the frontier, suggesting inadequate control of OM. In terms of the ASDR, the burden in Papua New Guinea, Somalia, and Niger is closer to the ideal benchmark, while countries such as Lithuania, Latvia, and the Estonia still have significant room for improvement in reducing the burden of OM. Detailed data on frontier analysis for various countries is presented in Fig. 5 and Table S4.

Fig. 5

Frontier analysis of OM in children in 204 countries and regions in 2021. (A, B) Gap in ASIR between different countries and the frontier; (C, D) Gap in ASDR between different countries and the frontier. The top 15 countries furthest from the frontier are marked in black; countries with low SDI (< 0.47) and nearest to the frontier are marked in blue; countries with high SDI (> 0.81) and furthest from the frontier are marked in red. Red dots indicate an increase in ASIR and ASDR from 1990 to 2021; blue dots indicate a decrease in ASIR and ASDR from 1990 to 2021

Forecast analysis in global and five SDI regions

From 2022 to 2050, the global incidence of OM is projected to increase from 256.30 million cases in 2021 to 333.54 million by 2050, while the ASIR is expected to remain stable. The rise in case numbers is primarily attributed to low-SDI areas, in which the number of cases is projected to increase from 79.71 million in 2021 to 109.81 million in 2050. Meanwhile, case numbers in other SDI areas are expected to remain relatively stable or continue to decline. In terms of ASIR, middle- and low-SDI areas show a downward trend, while other SDI areas remain stable (Tables S5–S6, Fig.S4).