Establishment of Reference Values for Insulin-like Growth Factor 1 (IGF1) in the General Population

Study Overview
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Brief Summary
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Various assays can be used for IGF-I measurement in French laboratories. Unfortunately, each assay gives a very different result for the same sample. As IGF-I also varies with age, it is necessary to establish a broad population reference values of IGF1 concentration for each of the IGF1 assays used in clinical practice, taking into account individual variation factors such as age, nutritional status and possible treatments. The objective of this study is to establish normative data based on a large random selection from the general population, including representation from all age groups (around 100 subjects for each decade age range). This will be performed for all the available assay kits. Subjects with medical conditions and medications that may affect the outcome will be excluded. Normative data will include the range (2.5 to 97.5 percentiles) in mass units and results will be reported as mass units but also as SD scores in order to be able, in a given patient, to compare its IGF-I concentration along time, even if using different assays.

Detailed Description
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Healthy subjects will be recruited in 30 centers all around France. A total of 1000 healthy subjects are necessary. Each subject will have a clinical examination with measurement of height and weight. Personal medical history will be recorded and gonadal status evaluated. Biological standard workup will be performed and 80 ml of blood will be sampled and serum will be aliquoted, frozen and stored at -80°C. IGF-I level will be measured with all the assay methods available (sera kept in bank will be used in the future when new methods will be available) For each assay method and each age group (Four 3-years groups between 18 and 30 years and six decade age groups between 30 and 89 years) IGF-I will be measured. Results will be expressed as mean, median, standard deviation, 2.5th and 97.5th percentiles, in mass units. Modelisation according to age and other factors will be performed in order to allow the reporting of IGF-I results for a given individual expression of IGF-I as Z-score.

Official Title
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An Open, Prospective, National, Multicenter, Non Randomised, Study Based on Healthy Volunteers for Establishing Normative Data for IGF1 in the General Population

Conditions
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Population

Intervention / Treatment
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* Other: Blood sample


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female 18 to 89 years old (18 years ≤ age ≤ 89 years) Consent given by the patient No history of : thyroid disease, liver disease or kidney disease or metabolic endocrine disease cardiovascular or pulmonary disease, neoplastic disease, gastroenterological disease (malabsorption, parasites, chronic diarrhea, peptic disease), psychiatric illness, epilepsy. No medication that can interfere with the concentration of IGF1: steroids, anti-androgens, distal diuretics, anti-estrogens, enzyme inducers (rifampin, rifabutin, phenobarbital, phenytoin, carbamazepine, herbal St. John's wort, efavirenz, nevirapine, griseofulvin , OP'DDD, mitotane). No intercurrent illness in the week preceding the inclusion No known chronic infectious disease (BVH, CVH, HIV) No active smoking Weight/height2 (BMI) less than 28 kg/m2 and greater than 19 kg/m2 Normal clinical examination Normal blood pressure: children under 65 years (100 mm Hg <SBP <140 mmHg, 50 mmHg <PAD <90 mmHg) for over 65 years (100 mm Hg <SBP <150 mmHg, 50 mmHg <SBP <90mmHg ) Exclusion Criteria: Uncontrolled intercurrent illness Pregnant or lactating woman Excess alcohol consumption: more than 50 g/24h of chronic or acute or unable to restraint from consuming alcohol Susceptible to use drugs Donated blood in the 3 months preceding the study Blood transfusion in the 3 months preceding the test Exclusion period of a previous experimental trial. Fasting extended by several days. Patient not affiliated to a social security system (is or should be beneficiary)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 89 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Volonteers<br>Blood sample | Other: Blood sample<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concentration of IGF1 in serum | Establishment of reference values for the concentration of IGF1 in the general adult population for each of the assays of IGF1 used in clinical practice, taking into account individual variation factors such as age, nutritional status and potential treatments. | up to 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Development of an expression results in Z-score for all assays to overcome the differences related to different immunoassays. |  | up to 4 hours | 
| Establishment of a bank of frozen sera to further develop these standards |  | up to 4 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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IGF1, standards, Assays, Z-score, Healthy volunteers, Population