Global Estimates Reveal Significant Variability in Type 1 Diabetes Among Youth

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A recent meta-analysis and systematic review yielded updated insight into the global estimates of the incidence of type 1 diabetes (T1D) among children and adolescents under 20 years of age, with data spanning 55 countries and 18 regions.¹

Across 126 studies performed from 2000 to 2022, the incidence rate of T1D was estimated to be 14.07 per 100,000 person-years. Significant variability was observed by country, and region, with the highest rates observed in Finland and North America, and by age group, with a higher incidence among those aged 10 to 14 years.

“More reliable data from additional countries are needed to determine the worldwide incidence of T1D,” wrote the investigative team, led by Yasmin Ezzatvar, department of nursing at the University of Valencia.

Estimates suggest more than 1.2 million children and adolescents globally have T1D.² Previous research has assessed the incidence of T1D among those aged ≤15 years, but no meta-analysis has been performed to provide pooled estimates of T1D among those aged <20 years, particularly by age and sex. There also remain questions on the impact of the COVID-19 pandemic on the incidence of T1D in the pre-pandemic and post-pandemic periods.

For this analysis, Ezzatvar and colleagues estimated the global incidence rate of T1D among those aged <20 years over more than 20 years, from 2000 to 2002.¹ Two reviewers searched PubMed, Web of Science, and CINAHL to identify relevant articles to T1D incidence during the study period.

The pooled estimates of T1D incidence, using 95% confidence intervals (CIs) per 100,000 person-years, were assessed by country and region, sex, age, and the COVID-19 pandemic period. After an initial identification of 7247 studies, the application of inclusion and exclusion criteria left a total of 126 studies for analysis. Studies included in the analysis reported 183,005 new cases of T1D during the study period and 23 studies encompassed both the pre-pandemic period (2017 to 2019) and the COVID-19 pandemic period (2020 to 2022).

Upon analysis, investigators found the average incidence rate of T1D per 100,000 person-years was 14.07 (95% CI, 12.15 -16.29). Both Finland and high-income North America experienced the highest incidence rates, at 56.81 (95% CI, 55.91 - 57.73) and 28.78 (95% CI, 26.60 - 31.14), respectively.

Moreover, subgroup analyses examined variables including, sex, age, and COVID-19 period categories. The incidence rate of T1D was 13.37 (95% CI, 10.60 - 16.88) per 100,000 person-years in boys and 13.87 (95% CI, 11.51 - 16.70) per 100,000 person-years in girls.

During the study period, the overall incidence rates for children and adolescents in age groups 0 to 4 years, 5 to 9 years, 10 - 14 years, and 15 to 19 years were 9.66 (95% CI, 7.83 - 11.92), 16.83 (95% CI, 13.88 - 20.41), 18.96 (95% CI, 15.81 - 22.74), and 7.05 (95% CI, 4.38 - 11.34), respectively.

There were statistically significant differences between age groups: 0 to 4 years versus 5 to 9 years (P <.001), 0 to 4 years versus 10 to 14 years old (P <.001), 5 to 9 years versus 15 to 19 years (P = .001), and 10 to 14 years versus 15 to 19 years old (P <.001).

Investigators indicated the incidence of T1D during the pandemic period was higher than the incidence during the pre-pandemic period. According to the analysis, the incidence rate was 24.84 (95% CI, 17.16 - 35.96) per 100,000 person-years in the pandemic period, compared to 13.56 (95% CI, 7.49 - 24.56) per 100,000 person-years in the pre-pandemic period. However, the difference was not statistically significant (P = .090).

Ezzatvar and colleagues noted that while multiple hypotheses have been introduced on the association between COVID-19 and higher incidence of T1D, there is no strong evidence of causation between COVID-19 and the disease.

“Therefore, the available data on T1D incidence during the COVID-19 pandemic remains inconsistent, and long-term follow-up studies are needed,” investigators wrote.

References

1. _{Hormazábal-Aguayo I, Ezzatvar Y, Huerta-Uribe N, Ramírez-Vélez R, Izquierdo M, García-Hermoso A. Incidence of type 1 diabetes mellitus in children and adolescents under 20 years of age across 55 countries from 2000 to 2022: A systematic review with meta-analysis. Diabetes Metab Res Rev. Published online December 1, 2023. doi:10.1002/dmrr.3749}
2. _{IDF diabetes atlas 2021. IDF Diabetes Atlas. 2021. Accessed December 13, 2023. https://diabetesatlas.org/atlas/tenth-edition/.}