The purpose of this research study is to determine which measures best capture cardiovascular disease (CVD) risk and type 2 diabetes (T2DM) risk in children and adolescents with Down syndrome (DS). We hypothesize that DS is associated with worse cardiometabolic risk factors for a given body mass index compared to controls. This difference arises at least in part, from increased fat tissue.
DS affects 1 per 800 births and is one of the most common causes of developmental disability in the US. Life expectancy for Down syndrome has increased significantly: estimated median survival in the US in 1997 was 49 years. DS is associated with an increased risk for obesity, with an estimated prevalence of 47-48% in adults and 30-50% in children with DS. Adolescents with DS are more likely to have increased adiposity compared to unaffected peers and may be at increased risk for obesity-related co-morbidities, such as type 2 diabetes and cardiovascular disease. How one defines obesity in DS is not clear. Individuals with DS have short stature and possibly increased adiposity, and the body mass index (BMI) used to define obesity for otherwise healthy populations may not accurately depict body fatness or capture cardiometabolic risk in DS. Congenital heart disease (CHD) affects approximately 50% of individuals with DS; the National Institutes of Health Heart Lung and Blood Institute (NHLBI) Working Group on Obesity and Other Cardiovascular Risk Factors in Congenital Heart Disease highlighted the high prevalence of obesity in the setting of CHD, and called for studies to identify obesity measures that are more sensitive than BMI as well as studies of CVD risk prevention. Unfortunately, clinicians caring for obese adolescents with DS with or without CHD have little scientific evidence upon which to base guidance regarding cardiometabolic risk (CMR): data regarding CVD risk and prevalence of pre-diabetes and T2DM in obese adolescents with DS are lacking. The measure of body fatness which best predicts CMR in DS is not known. We plan to compare BMI and other measures of body fatness in healthy controls and adolescents with DS to determine which measures best capture CVD and/or T2DM risk. These data will equip medical providers with the tools to better assess risk, initiate prevention measures, and guide screening in adolescents with DS.
Study Type
OBSERVATIONAL
Enrollment
257
Children's National Medical Center
Washington D.C., District of Columbia, United States
The Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States
Non-HDL Cholesterol
Non-HDL cholesterol measured via fasting blood draw
Time frame: Study Visit 1
Lipid Subparticles
Lipoprotein subclass particle analysis run on samples from fasting blood drawn Study Visit 1.
Time frame: Study Visit 1
Lipid Subparticles (Size)
Lipoprotein subclass particle analysis run on samples from fasting blood drawn Study Visit 1.
Time frame: Study Visit 1
Insulin Resistance
Insulin Resistance (HOMA-IR) was calculated as \[fasting insulin (uIU/mL) x fasting glycemia (mmol/L)\]/22.5
Time frame: Study Visit 1
Cardiometabolic Risk Biomarker Proteins
hs-CRP, PAI-1, and IL-6 run on samples from fasting blood drawn Study Visit 1.
Time frame: Study Visit 1
Abnormal Glucose Tolerance
Impaired fasting glucose (IFG) was defined as fasting glucose ≥ 100 mg/dl. Impaired glucose tolerance (IGT) was defined as 2-hour glucose 140-199 mg/dl measured as part of an oral glucose tolerance test.
Time frame: Study Visit 1
Visceral Fat
Adiposity measured by Dual-energy X-ray absorptiometry
Time frame: Study Visit 1
Body Mass Measures
Adiposity measured by Dual-energy X-ray absorptiometry
Time frame: Study Visit 1
Left Ventricular Mass
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Cardiac end organ injury assessed by echocardiography. Left Ventricular Mass (LVM) was measured by area/length method using the apical four-chamber and parasternal short-axis views. LVM was calculated as LV area × LV length × 1.05 × 5/6.
Time frame: Study Visit 1
Pulse Wave Velocity
Cardiac end organ injury assessed by Pulse Wave Velocity (PWV)
Time frame: Study Visit 1
Health Related Quality of Life - PedsQL
Caregiver-perception of his/her child's health-related QOL was assessed with the use of the parent-proxy report of the Pediatric Quality of Life Inventory (PedsQL) Version 4.0. Sub-scale scores are converted to a 0-100 scale so that greater scores indicate better QOL. Scale scores are computed as the sum of the items divided by the number of items answered (this accounts for missing data). If more than 50% of the items in the scale are missing, the scale score is not computed. The Physical Health Summary Score (8 items) is the same as the Physical Functioning Scale. To create the Psychosocial Health Summary Score (15 items), the mean is computed as the sum of the items divided by the number of items answered in the Emotional, Social, and School Functioning Scales.
Time frame: Study Visit 1
Health Related Quality of Life - IWQOL
Parent perception of the effects of weight on his/her child's QOL was assessed with a caregiver-proxy version of the Impact of Weight on Quality of Life - Kids (IWQOL-Kids) questionnaire. The IWQOL-Kids is a validated, 27-item, self-report measure of weight-related QOL for youth ages 11-19 years. It yields 4 subscales (Physical Comfort, Body Esteem, Social Life, and Family Relations) and a Total score, which have strong psychometric properties, discriminate among weight status groups, and are responsive to weight change. Scaled scores are standardized and range from 0 to 100, with greater scores representing better weight-related QOL.
Time frame: Study Visit 1