An observational study in Down Syndrome (Trisomy 21), sponsored by University of Nevada, Las Vegas. Recruiting at 1 site in United States. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-02.
Sponsored by University of Nevada, Las Vegas · Observational
Adults with Down syndrome (Ds) are often thought to have a lower risk of heart and blood vessel disease because they tend to have lower blood pressure (BP) and fewer heart attacks than people without Ds. However, recent research suggests that heart and blood vessel diseases, including stroke, are becoming a more common cause of death in adults with Ds as life expectancy increases. Despite these findings, studies examining heart and blood vessel health in adults with Ds have produced mixed results, making it difficult to determine their true risk and whether preventive strategies are needed. This study will investigate the health of blood vessels in adults with Ds and compare the results with those of adults without Ds. Healthy blood vessels are important because they help deliver blood and oxygen throughout the body. Changes in blood vessel function and stiffness can occur with aging and may increase the risk of heart disease, stroke, kidney disease, and memory problems. The study aims to determine whether adults with Ds experience changes in blood vessel health that may place them at increased cardiovascular risk. Specifically, the study will: (1) Examine how well blood vessels function in adults with Ds; (2) Measure the stiffness of arteries in adults with Ds; (3) Compare two methods used to assess blood vessel function to determine whether a simpler exercise-based test provides results similar to a commonly used standard test. The findings may improve understanding of cardiovascular risk in adults with Ds and help guide future strategies to promote healthy aging in this population.
This proposal challenges the conventional wisdom that adults with Down syndrome (Ds) are at a lower risk for cardiovascular disease (CVD) because they have low blood pressure and fewer heart attacks than their peers without DS. Recent studies show a larger and increasing contribution of non-congenital CVD (including stroke) to mortality in adults with Ds, likely due to the increased life expectancy. Despite this, studies on traditional cardiovascular risk indicators in adults with DS are conflicting. This currently results in limited urgency for implementing risk-lowering strategies. To address this gap in knowledge and methodology, our overall aim is to demonstrate accelerated vascular aging in adults with Ds, defined by age-related yet Ds-specific endothelial dysfunction and arterial stiffness. Vascular aging directly measures the disease progression towards organ damage, such as the brain and the kidneys, which leads to cardiovascular disease, stroke, and Alzheimer's disease (AD) in the general population. Adults with Ds experience excessive syndrome-specific chronic vascular adaptations, which may accelerate vascular aging. However, this has not yet been investigated.
This project aims to provide a more direct and accurate measure to determine cardiovascular risk by comprehensively characterizing vascular health in adults with Ds compared to adults without Ds.
Aim 1: To identify the effect of Ds on endothelial function. Aim 2: To identify the impact of Ds on arterial stiffness. Aim 3: To compare measurements of endothelial function using a hand grip (HG) exercise protocol and the gold standard flow-mediated dilation protocol (FMD).
A cross-sectional research design is used for all aims and includes a comprehensive evaluation of endothelial function and arterial stiffness. Both participants with Ds and a sex-matched control group of participants without Ds or other intellectual disabilities (from here on, control participants) will be included.
Familiarization. The investigators involve parents/caregivers to provide a supportive environment for participants and to enhance the parent's/caregiver's understanding of the research with videos and practice sessions.
Description of data collection visits. Data collection will be completed in two study visits of maximal 2h each. The investigators will first obtain a signed informed consent form explaining our study procedures, potential risks, and benefits of the study from the participants and/or their legally authorized representative, if present. During the first data collection visit, after discussing the study and potential questions, participants and/or their legally authorized representative will complete the International Physical Activity Questionnaire (IPAQ) to confirm eligibility. Participants will be tested in a postprandial state (>3 h) and will refrain from drinking or eating caffeine and drinking alcohol and from exercise 24 h before both the test days. Females will be studied during the first 3-5 days of menses to control for hormonal variation. Baseline measurements will include anthropometric assessments of height, weight, and circumference. Body composition will be measured with a dual x-ray absorptiometry (DEXA) scan to record forearm composition and mass. For arterial stiffness assessment, participants will lie down while their arterial Pulse Wave Velocity (PWV) and Augmentation Index are measured using a brachial blood pressure monitor (Mobil-O-Graph) and carotid-femoral tonometry (PulsePen). Carotid Beta-Stiffness and intima-media thickness (IMT) will be evaluated via carotid ultrasonography (Hitachi Arietta 70). The second visit will include an assessment of endothelial function. Participants will lie down and perform a 2-minute isometric hand grip test (HG) at 30% of maximum voluntary contraction (MVC), followed by a flow-mediated dilation (FMD) protocol with a cuff occlusion of 50 mmHg above systolic blood pressure on the forearm for 5 minutes. Brachial artery dilation and blood flow will be assessed after HG and FMD using high-resolution ultrasonography (Arietta 70, Hitachi, Tokyo, Japan).
438 studies on the registry are indexed under Down Syndrome; 99 are open to participants now.
This study's planned enrollment of 46 is below the median of 158 across 145 observational studies indexed under Down Syndrome.
Browse Down Syndrome studies →University of Nevada, Las Vegas is the lead sponsor of 75 studies on the registry; 22 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 2 (40%) have results posted.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 2, 2026. See what changed
The population being evaluated by the protocol consists of a convenience sample of individuals with Down syndrome (Ds) between the ages of 18 and 35 years old, and a group of control participants without Ds matched for age and sex, living in the community. 43 participants will be enrolled in the study at UNLV: 23 individuals with Down syndrome and 23 individuals without Down syndrome.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Additionally, for the participants with Down syndrome:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adults with Down Syndrome
Age- and sex-matched adults without Down Syndrome
Carotid-femoral pulse wave velocity (PWV).
PWV (m/s) will be measured using small, non-invasive pressure-sensitive transducers that record distension waveforms over superficial arteries like the carotid and femoral artery (PulsePen® DiaTecne - Italia).
Time frame: Through study completion, on average 4 hours
Augmentation index
Defined as the ratio of Augmentation Pressure (AP) to the total Pulse Pressure (PP), expressed as %. It will be measured using small, non-invasive pressure-sensitive transducers that record distension waveforms over superficial arteries (PulsePen® DiaTecne - Italia).
Time frame: Through study completion, on average 4 hours.
Carotid Beta-stiffness
The carotid Beta-stiffness index is a unitless measurement. It quantifies the intrinsic stiffness of the common carotid artery using high-definition ultrasound (Hitachi Arietta 70 system, Tokyo, Japan).
Time frame: Through study completion, on average 4 hours.
Intima-Media Thickness
An ultrasound-based assessment of intima-media thickness (IMT) for the carotid artery. Thickness will be calculated as the distance (mm) from the leading edge of the intima to the beginning of the adventitial layer of the top and bottom walls.
Time frame: Through study completion, on average 4 hours.
Change in Blood Flow after isometric hand grip exercise.
Participants will perform a 2-minute isometric hand grip exercise at 30% of MVC. Brachial artery blood flow (mL/min) will be assessed using high-resolution ultrasonography (Arietta 70, Hitachi, Tokyo, Japan) and expressed as a percentage of baseline measurements, normalized to forearm lean mass.
Time frame: Through study completion, on average 4 hours.
Change in Blood Flow after occlusion
Participants will undergo a flow-mediated dilation (FMD) protocol, in which a pneumatic cuff will be placed around the forearm and inflated to 50 mmHg above systolic levels for 5 minutes. Brachial artery blood flow (mL/min) will be assessed using high-resolution ultrasonography (Arietta 70, Hitachi, Tokyo, Japan) and expressed as a percentage of baseline measurements, normalized to forearm lean mass.
Time frame: Through study completion, on average 4 hours.
Plan to share: No — De-identified IPD will be made available to other researchers upon request.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Nevada, Las Vegas