Trends in the Prevalence of Down Syndrome through the COVID-19 era: An examination of the National Survey of Children’s Health, 2016-2022

Introduction: Down Syndrome (DS) is the clinical manifestation of Trisomy 21 and is the most prevalent chromosomal abnormality in live births, contributing to cardiovascular abnormalities and intellectual disability. Although lifetime prevalence of DS is increased compared to 1950, precise calculations remain stringent due to limited birth registries and limited data availability. The prevalence of DS increases with increasing maternal age and medical advancements leading to longer survival of individuals with DS and decreases with early termination of pregnancy following prenatal diagnosis and decreasing overall birth rates. Since the 1990s, these opposing factors have resulted in a stabilization of DS prevalence. However, the DS prevalence has not been explored throughout the COVID-19 pandemic era. Thus, this study aims to assess changes in the prevalence of DS among children under 18 years of age from 2016 to 2022 and potential disparities by ethnoracial groups.

Methods: In this cross-sectional analysis, we analyzed the prevalence of DS using the National Survey of Children’s Health (NSCH) from 2016 through 2022. We used a design-based X² test to determine if the prevalence of DS differed among the years and regression to determine the presence of a trend. We also estimated the prevalence of DS by ethnoracial groupings and tested for differences using a X² test. Survey design and sampling weights provided by the NSCH were employed and adjusted for analyses requiring multiple years of data, according to the NSCH methods manual.

Results: From 2016 to 2022, the prevalence of DS exhibited notable fluctuations among the 278,538 individuals sampled, with 603 individuals reported their child having DS. Specifically, the weighted percent of DS prevalence increased overall from 0.14% in 2016 to 0.26% in 2022, revealing a statistically significant 0.022% annual increase via regression analysis (95% CI: 0.0072%-0.037, t=2.92, P=.004; Table 1).

By ethnoracial group, the prevalence of DS was highest among American Indian/Alaska Native (0.45%), Native Hawaiian/Other Pacific Islander (0.30%), and Hispanic children (0.22%), though the distribution of DS among ethnoracial groupings was not statistically significant for the combined years (X²_{(4.83, 1.3e+06)}= 0.84, P = .52; Table 2).

Conclusion: To our knowledge, this is the first study to assess the prevalence of DS among children through the COVID-19 pandemic, which found a significant increase in its prevalence from 2016 through 2022. While we do not suggest nor are we aware of any correlation between DS prevalence and the COVID-19 pandemic, a variety of social, demographic, genetic, or other factors could be at play to explain this observed increase, such as average maternal age or rates of conception and childbirth.

In conclusion, our study contributes to the evolving landscape of DS prevalence and highlights the importance of considering external factors in shaping health outcomes. The observed variations in DS prevalence among diverse populations underscore the complexity of such genetic disorders and emphasize the necessity for multifaceted, inclusive research to guide public health interventions.