Effects of different doses of oral Cholecalciferol on serum 25-OHD,PTH, Calcium,and bone markers during Fall and Winter in school children of Taleghan

INTERVENTION: 50 000 units of oral vitamin D3 bimonthly during 6 months. 50 000 units of oral vitamin D3 monthly during 6 months. Intervention 1: 50 000 units of oral vitamin D3 monthly during 6 months. Intervention 2: Placebo monthly, similar to the real drug in shape for 6 months. Intervention 3: 50 000 units of oral vitamin D3 bimonthly during 6 months. Placebo Placebo monthly, similar to the real drug in shape for 6 months Treatment ‐ Drugs CONDITION: Status of vitamin D in school children. ; Vitamin D deficiency, unspecified Vitamin D deficiency, unspecified PRIMARY OUTCOME: Serum levels of 25‐OHD. Timepoint: at the begining, middle, and end of the study. Method of measurement: RIA. SECONDARY OUTCOME: 24 hour urine c‐telopeptide. Timepoint: At the beginning, middle, and the end of the study. Method of measurement: RIA. Serum levels of bone specific alkaline phosphatase. Timepoint: At the beginning, middle, and the end of the study. Method of measurement: RIA. Serum levels of Calcium. Timepoint: At the beginning, middle, and the end of the study. Method of measurement: RIA. Serum levels of iPTH. Timepoint: At the beginning, middle, and the end of the study. Method of measurement: RIA. Serum levels of osteocalcin. Timepoint: samples were taken at the begining, middle, and end of the study. Method of measurement: RIA. INCLUSION CRITERIA: INCLUSION CRITERIA: All healthy active students. Exclusion criteria: Those with disorders affecting bone metabolism or taking supplements or drugs affecting bone metabolism.