Here is the design of a clinical trial:

Official Title: Efficacy of Oral Vitamin D Supplementation in Reducing Body Mass Index and Lipid Profile in Adolescents and Young Adults in Colombia: a Pilot Clinical Trial Protocol Nested in the SIMBA Cohort

Included conditions:
- Overweight and Obesity
- Overweight Adolescents
- Vitamin D Deficiency

Study Armgroups:
- {'label': 'Intervention group: 1000 IU DV', 'type': 'EXPERIMENTAL', 'description': 'The 75 participants assigned to the intervention group will take 1 DV capsule of 1000 IU daily for 15 weeks.', 'interventionNames': ['Dietary Supplement: 1000 IU D vitamin']}
- {'label': 'Control group: 200 IU DV', 'type': 'PLACEBO_COMPARATOR', 'description': 'The 75 participants of the control group will take 1 DV capsule of 200 IU daily for 15 weeks, this dose being the minimum recommended for children. The above, considering that it is ethical for the control group to receive a minimum dose of supplementation.', 'interventionNames': ['Dietary Supplement: 200 IU D vitamin']}

Interventions:
- {'type': 'DIETARY_SUPPLEMENT', 'name': '1000 IU D vitamin', 'description': 'Participants in the intervention group will receive 105 DV doses of 1000 IU. The supplementation will be given by the Farma de Colombia laboratory, known commercially as Farma D, whose presentation is in soft gelatin capsules. It is recommended to take one dose per day at the same time and participants should record the daily intake time of the supplement for 15 weeks on a calendar.', 'armGroupLabels': ['Intervention group: 1000 IU DV'], 'otherNames': ['Supplementation with 1000 IU vitamin D', 'Farma D 1000 IU']}
- {'type': 'DIETARY_SUPPLEMENT', 'name': '200 IU D vitamin', 'description': 'Participants in the control group will receive 105 DV doses of 200 IU. The supplementation will be given by the same laboratory; it will have the same characteristics and recommendations for the intake as for the intervention group.', 'armGroupLabels': ['Control group: 200 IU DV'], 'otherNames': ['Supplementation with 200 IU vitamin D', 'Farma D 200 IU']}

Primary Outcomes:
- {'measure': 'Change in body mass index between baseline and week 15', 'description': 'Change in body mass index (BMI) will be made through of the measure of body weight will be in kilograms (kg) to one decimal place, and the size in meters (m) to two decimal places. From these measurements the body mass index will be obtained using the formula: BMI = Weight (kg) / size (m)2.', 'timeFrame': 'Baseline and week 15'}
- {'measure': 'Change in lipid profile (Total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides) between baseline and week 15', 'description': 'Serum is measured from the same blood samples drawn for vitamin D levels. The processing and analysis of the samples will be done respectively through enzymatic technique, selective liquid detergent, selective detergent accelerator and Glycerol Phosphate Oxidase.', 'timeFrame': 'Baseline and week 15'}
- {'measure': 'Change in 25-hydroxyvitamin D [25(OH)D] levels between baseline and week 15', 'description': 'After a 10-12 hour fast, in peripheral venous blood 25-hydroxyvitamin D \\[25(OH)D\\] is quantified in serum by chemiluminescent microparticle immunoassay (CMIA).', 'timeFrame': 'baseline and week 15'}

Please estimate the sample size based on the assumption: 
A power of 90%, an alpha of 5%, an intervention group/control group ratio of 1:1, and a 20% adjustment for losses to follow-up
3.3
        Sample size
        The simple size was calculated considering the following parameters: an expected difference in the study outcomes (overweight, obesity, and alteration of the lipid profile) of 20% between the intervention group and the control group; a power of 90%, an alfa of 5%, an intervention group/control group ratio of 1:1, and a 20% adjustment for losses to follow-up, resulting in a sample of 270 participants (nâ=â135 intervention and nâ=â135 control group). The OpenEpi software was used for the calculation. Since this is a pilot study and considering the feasibility, the research team decided on a sample size of 150 participants (nâ=â75 intervention group and nâ=â75 control group).