This Study Will Evaluate Cardiorespiratory and Muscular Fitness to Examine Associations With Anthropometric Characteristics and Other Indicators of Cardiometabolic Risk Among Patients With or Without Autism Spectrum Disorder

Pediatric obesity and cardiometabolic health problems are major public health concerns. Children with obesity may have a higher risk of developing conditions such as insulin resistance, prediabetes, abnormal cholesterol levels, high blood pressure, and cardiovascular disease later in life. In clinical practice, body mass index (BMI), body measurements, and blood tests are commonly used to assess health risk. Although these measures provide important information, they do not fully describe how well a child's heart, lungs, and muscles work during physical activity. Cardiorespiratory fitness (CRF) provides information about the body's ability to use oxygen during exercise and reflects the combined function of several body systems. Higher levels of CRF have been associated with better cardiometabolic health and a lower risk of future disease.

Fitness testing is not routinely used in pediatric clinical settings. Traditional CRF testing may require specialized equipment and exercise at maximal intensity, which can be difficult for some children and may not be practical during a routine clinic visit. Simple, clinically feasible tests, such as the 3-minute step test (3MST), may provide a practical way to assess cardiorespiratory fitness without requiring expensive equipment or maximal exercise. Handgrip strength (HGS) testing is another simple measure that can provide information about muscular fitness and physical function. These tests may be especially useful in pediatric populations because they can be completed in a relatively short period of time and require limited equipment.

Research has shown that cardiorespiratory and muscular fitness are related to several measures of cardiometabolic health, including body composition, blood glucose, cholesterol levels, and other risk factors for metabolic and cardiovascular disease. However, less is known about how these fitness measures relate to cardiometabolic health in children with obesity who are evaluated in routine clinical care, particularly among children with autism spectrum disorder (ASD). Children with ASD may have differences in physical activity, motor skills, and participation in exercise that could affect fitness and cardiometabolic health.

This study will examine cardiorespiratory and muscular fitness in children with obesity, with and without ASD. The study will evaluate whether differences in fitness are associated with body measurements, body composition, and markers of cardiometabolic health, including blood glucose and lipid measures. The findings may improve understanding of the relationship between physical fitness and cardiometabolic health in children with obesity and may help determine whether simple fitness assessments can provide useful information during pediatric clinical evaluations. In the future, these assessments may support more individualized exercise recommendations and contribute to strategies for improving long-term cardiometabolic health in children.

Inclusion criteria

• Pediatric patients 6-18 years of age who received care at the Pediatric Endocrinology Diabetes Prevention and Fitness Clinic between January 1 and December 31, 2026.
• BMI ≥95th percentile for age and sex, consistent with the definition of pediatric obesity.
• Documented results from cardiorespiratory fitness testing and/or handgrip strength testing.
• Documented HbA1c value, when available.
• Sufficient medical record information to determine ASD status and the primary study outcomes.

Exclusion criteria

• Age <6 or >18 years at the time of clinical assessment.
• BMI <95th percentile for age and sex.
• Absence of documented cardiorespiratory fitness or handgrip strength testing.
• Insufficient medical record information to determine ASD status or primary study outcomes.
• Duplicate or unusable medical records.