Arthritis Among Children and Adolescents Aged <18 Years — United States, 2017–2021

Arthritis affects persons of all ages, including younger adults, adolescents, and children; however, recent arthritis prevalence estimates among children and adolescents aged <18 years are not available. Previous prevalence estimates among U.S. children and adolescents aged <18 years ranged from 21 to 403 per 100,000 population depending upon the case definition used. CDC analyzed aggregated 2017-2021 National Survey of Children's Health data to estimate the national prevalence of parent-reported arthritis diagnosed among children and adolescents aged <18 years. An estimated 220,000 (95% CI = 187,000-260,000) U.S. children and adolescents aged <18 years (305 per 100,000) had diagnosed arthritis. Arthritis prevalence among non-Hispanic Black or African American children and adolescents was twice that of non-Hispanic White children and adolescents. Co-occurring conditions, including depression, anxiety, overweight, physical inactivity, and food insecurity were associated with higher prevalences of arthritis. These findings highlight that children and adolescents should be prioritized for arthritis prevention and treatments by identifying risk factors for arthritis, developing self-management interventions to improve arthritis, physical activity or weight control, and screening and linking to mental health services. Health systems and payors can take steps to ensure equitable access to therapies (e.g., physical therapies and medications).


Introduction
Previous estimates of the number of arthritis cases and prevalence among U.S. children and adolescents aged <18 years range from 13,400 (21 per 100,000 population) in one 1978 study using a very narrow definition of juvenile arthritis (1) to 294,000 (403 per 100,000) during 2001-2004 using a much broader definition of pediatric arthritis and other rheumatologic conditions (2).Although children and adolescents can receive diagnoses of many types of arthritis, the most common are acquired autoinflammatory diseases* that are associated with joint pain, swelling, stiffness, physical disability, and activity limitation that often persist into adulthood; depression and anxiety often co-occur with arthritis among children and adolescents (3,4,5).The National Survey of Children's Health (NSCH) is an annual household survey conducted by the U.S. Census Bureau designed and funded by the Health Resources and Services Administration's Maternal and Child Health Bureau.It is the largest national-and state-level survey of U.S. children's health and uses a national address-based sample for online or mail collection of data from parents.† NSCH asks parents about the physical and emotional health, well-being, and related factors of one randomly selected §, ¶ child or adolescent aged <18 years from their household.

Methods
The overall NSCH response rates during 2017, 2018, 2019, 2020, and 2021 were 37.4%, 43.1%, 42.4%, 42.4%, and 40.3%, respectively.Diagnosed arthritis was defined as parents answering "yes" to the single question, "Has a doctor or other health care provider ever told you that this child has arthritis?"These analyses included combined 2017-2021 public use deidentified data from parents who answered the question about arthritis for the selected child or adolescent, resulting in a study population of 173,406 children and adolescents aged <18 years.
Annualized, unadjusted prevalence estimates of arthritis (cases per 100,000 U.S. children and adolescents) were generated overall and by selected characteristics of the child or adolescent (e.g., demographic characteristics; depression, anxiety, or overweight; physical inactivity; and having health insurance or a place for preventive care) and characteristics of the household (e.g., parents' highest educational attainment, whether smoking occurs in the household, and presence of food insecurity).All estimates presented were weighted to be nationally representative of the U.S. population of children and adolescents living in households.** ,† † Differences in subgroups were tested against a reference group using a t-test with an a priori α-level of 0.05.Analyses accounted for the complex survey design and were conducted using SAS-callable SUDAAN (version 11.0.1;RTI International).This activity was reviewed †

Results
During 2017-2021, an estimated 220,000 U.S. children and adolescents aged <18 years had arthritis, equating to a prevalence of 305 per 100,000 U.S. children and adolescents (Table ).Arthritis prevalence increased with age, from 77 per 100,000 among children aged <6 years to 592 among those aged 12-17 years.Prevalence was higher among non-Hispanic Black or African American (Black) children and adolescents (571 per 100,000) than among non-Hispanic White (White) children and adolescents (260).Among children and adolescents with reported co-occurring conditions, prevalence was highest among those with diagnosed depression (1,980), a heart condition (1,900), or anxiety (1,310), as well as among those who had overweight (1,040).Among children and adolescents ≥6 years, arthritis prevalence was higher among those who were physically inactive (791) than those who were active 1-3 days (409), 4-6 days (282) or everyday (331).The prevalence was also higher among children and adolescents in households with food insecurity (905) or smoking (560) compared with that among children living in households without these characteristics (267 and 260, respectively).In addition, the prevalence of arthritis decreased as the level of parental educational attainment increased (534 per 100,000 among those whose parent had less than a high school education compared with 199 per 100,000 among children and adolescents with a parent with at least a 4-year college degree).

Discussion
This report found that during 2017-2021, an estimated 220,000 U.S. children and adolescents had an arthritis diagnosis, and prevalence was highest among those aged 12-17 years.Previous U.S. population estimates of arthritis among children and adolescents ranged from 13,400 to 294,000 cases, and prevalences of 21 to 403 per 100,000 population (1,2) Although arthritis can affect children and adolescents of all races and ethnicities, this study identified racial and ethnic disparities.Arthritis prevalence among Black children and adolescents was twice that among those who were White.Further, prevalence of arthritis was inversely related to the highest level of parental education attained.These disparities highlight the importance of addressing social determinants of health because the impacts on health and well-being can be seen as early as childhood.
Similar to other studies, the results of this analysis determined that arthritis prevalence was high among children and adolescents with anxiety and depression.A 2019 systematic review of depression and anxiety in patients with juvenile idiopathic arthritis (4) found higher prevalences of symptoms of depression and anxiety among juvenile idiopathic arthritis patients and their family members than among children and adolescents without juvenile idiopathic arthritis.This review also identified a need for further data on the effect of treatment of mental health symptoms on disease outcomes among children and adolescents with juvenile idiopathic arthritis.Further, the systematic review found that children and adolescents with arthritis who were experiencing anxiety and depression also had a poorer quality of life, underscoring the need to address mental health among children and adolescents with arthritis and their families (4).The U.S. Preventive Services Task Force recommends screening all persons aged 8-18 years for anxiety, ¶ ¶ and those aged 12-18 years for major depressive disorder.***The rationale for routine screening is to identify youths without an anxiety diagnosis who might benefit from effective treatment for anxiety disorders.
The current study also found associations between arthritis and food insecurity as well as overweight and physical inactivity.Children and adolescents with special health care needs who are also experiencing food insecurity have been found to  have increased prevalences of various negative health outcomes, including overweight or obesity (6).A healthy, age-appropriate diet is strongly recommended as a treatment strategy for children and adolescents with arthritis (7).However, more research on physical activity and weight management interventions for children and adolescents with arthritis is needed.Arthritis therapy guidelines for children and adolescents include pharmacologic and nonpharmacologic interventions and treatments (7)(8)(9).Pharmacologic treatments include antirheumatic drugs, which help preserve joints by blocking or slowing inflammation, and nonsteroidal antiinflammatory drugs to treat stiffness, pain, and fever (8,9).The 2021 American College of Rheumatology guideline for the treatment of juvenile idiopathic arthritis recommends nonpharmacologic interventions including physical and occupational therapy to improve range of motion, muscle strength, endurance, functional deficits, and activities of daily living (7).Although this American College of Rheumatology guideline does not make specific physical activity recommendations, the 2018 Physical Activity Guidelines for Americans † † † recommend that, for optimal health and fitness, children and adolescents aged 6-17 years should engage in 60 minutes of daily moderate-to-vigorous physical activity.Physically active children and adolescents experience improved cognition and fitness, stronger bones and muscles, have lower percentages of body fat, and lower risk for depression † † † https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf compared with inactive children and adolescents.Although preventing some types of arthritis among children and adolescents is challenging, early diagnosis and prompt treatment might prevent permanent joint damage, improve health outcomes, reduce health disparities, and maintain quality of life (10).

Limitations
The findings in this report are subject to at least five limitations.First, because of the cross-sectional nature of this survey, causality among selected characteristics and arthritis prevalence cannot be inferred.Second, parent-reported arthritis diagnoses cannot be validated by medical records.Third, recall and social desirability biases or of knowledge about arthritis or other health conditions might result in misclassification.Fourth, because of the rarity of arthritis among children and adolescents, estimates for all subgroups might not be stable or precise, as evidenced by the wide CIs.Finally, the single survey question about an arthritis diagnosis does not provide the opportunity to estimate the prevalence of or distinguish among arthritis subtypes and does not assess undiagnosed arthritis cases.

Implications for Public Health Practice
This study combined data across 5 years resulting in a large sample size, providing stable prevalence estimates of arthritis among U.S. children and adolescents with the most recently available data and filling a gap in nationally representative, population-based estimates of arthritis among children and adolescents.The findings from this report highlight children and adolescents to prioritize for arthritis prevention and treatment by identifying risk factors for arthritis among children and adolescents, developing self-management interventions to improve childhood arthritis, physical activity or weight control, and screening and linking children and adolescents to needed mental health services.Addressing social determinants of health and systemic factors that might contribute to disparities in arthritis prevalence needs to be prioritized.Health systems and payors can take steps to ensure equitable access to therapies (e.g., physical therapies and medications).