Down Syndrome | Treatment Trial of Subclinical Hypothyroidism in Down Syndrome

Down Syndrome research study

What is the primary objective of this study?

The purpose of this research study is to learn about the effects of treating subclinical hypothyroidism (SCH) with thyroid hormone replacement in children and adolescents with Down syndrome (DS). We hypothesize that treatment of SCH with thyroid hormone replacement will improve cardiometabolic health and quality of life.

Who is eligible to participate?

Inclusion Criteria: - Males and females, ages 8 - 20 years - Diagnosis of Down syndrome - Subclinical hypothyroidism: TSH level between 5 - 10 mIU/L, normal T4 - Parental/guardian permission (informed consent) and if appropriate, child assent - Females who are at least 11 years of age or who are menarchal must have a negative urine/serum pregnancy test - Committed to adherence to levothyroxine treatment and study completion Exclusion Criteria: - Pregnancy - Type 1/Type 2 diabetes - Chronic medical conditions or medication use that can affect growth, nutrition, blood glucose, insulin secretion, or thyroid function (such as lithium or certain seizure medications) - Current use of levothyroxine or anti-thyroid hormone - Cyanotic congenital heart disease, or pulmonary hypertension (as described by last echo report in subjects with CHD), or congenital heart disease considered medically unstable by the study cardiologists

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?

Down Syndrome

Subclinical Hypothyroidism

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.


Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

Treatment Phase: Months 6-18Subject who are found to have SCH at the 6-month visit will be randomized to receive either levothyroxine or placebo during months 6-12. Levothyroxine dose will be between 0.5 - 1 mcg/kg/day. There will be 1 blood draw visit at month 7.5 (6 weeks after randomization) and 1 study visit at month 12 that will provide the opportunity for dose adjustments if needed. From months 12-18, all subjects will receive levothyroxine. Levothyroxine dose will be between 0.5 - 1 mcg/kg/day. There will be one blood draw visit at month 13.5 that will provide the opportunity for dose adjustments if needed.

Observation Phase: Months 0-6Subjects will be observed for the first 6 months of the study to ensure that the subclinical hypothyroidism is persistent. Subjects who do not have SCH at 6 months will not proceed to the treatment phase. Subjects that have TSH >10 mIU/L during the 6 month Observational Phase will not be considered subclinical and will not qualify to continue the study. They will be referred to an endocrinologist for treatment.

Study Status

Active, not recruiting

Start Date: January 2013

Completed Date: July 1, 2019

Phase: N/A

Type: Interventional


Primary Outcome: Change in non-HDL cholesterol from baseline at 6, 12 and 18 months.

Secondary Outcome: Change in quality of life from baseline at 6, 12 and 18 months.

Study sponsors, principal investigator, and references

Principal Investigator: Andrea Kelly, MD, MSCE

Lead Sponsor: Children's Hospital of Philadelphia

Collaborator: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

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