 Methods: Skeletal Evaluation: Dual X-ray absorptiometry DXA, Lunar DPX-L and Lunar Pixi: Quantitative bone mass aBMD total body, femoral neck, lumbar spine and regional. Special software determines cortical width, medullar width, cortical density and trabecular density in mid femur. vBMD and skeletal size can be evaluated from existing measurement in femoral neck and third lumbar vertebrae from DXA scan by the method described by Carter. Ultrasound Lunar Achilles: Qualitative bone mass aBMD and bone width calcaneus. Peripheral computed tomography pQCT: Bone mass, bone size and skeletal structure. Finite element analyses: skeletal strength. Digital radiographs of the hand: Bone size and cortical thickness. Soft tissue Evaluation: DXA Lunar DPX-L: Quantitative lean body mass and fat mass. Peripheral computed tomography pQCT: Quantitative lean body mass and fat mass. Muscle function: Cybex apparatus: Qualitative muscle strength in lower extremities. Balance plate and physiotherapists test: Qualitative muscle capacity. Anthropometric evaluation: Electronic scale: Body weight. Holstein Stadiometer: Sitting and standing height. Harpender stadiometer: Segmental extremity length and width. Pubertal status: Tanner. Environmental Evaluation: Questionnaire: life-style, exercise history, nutrition, and hereditary factors. Bone metabolism: Bone formation: Alkaline phosphatase ALP, isoenzyme of bone specific ALP, osteocalcin bone GLA protein, procollagen 1 C-terminal propeptic P1CP. Bone resorption: Hydroxyproline, pyridinoline, deoxypyridinoline, carboxytelopeptid region ICTP and aminotelopeptid region NTX in blood and urine. Genetics: Polymorphism of Vitamin D receptor gene VDR, oestrogen receptor gene ER, androgen receptor gene AR, human growth hormone gene GH 1, collagen 1 A gene COLL1A and additional bone related genes that will occur the next years. Hormones: Growth hormone, IGF-1, testosterone, estradiol, luteinisating hormone, follicle stimulating hormone, sex hormone binding globulin SHBG, androstenedione, dehydroepiandrostenedione DHEAS. Fractures: The fractures are registered in the files at the Dept. of Radiology, MAS where referrals, reports and films are saved since last century. Questionnaire: Epidemiologic fracture screening. Physiologic Evaluation: Blood pressure rest: Upper right arm. Bicycle test: Max working capacity by evaluating VO2 MAX. and CO2 production in breath. Bio impedance: Fat percent in total body. Spirometry: Static and dynamic lung function measured by the IOS-method. Ultrasound: Volume and wall thickness of heart. Accelerometer: Number of steps during four days is measured within this minicomputer fastened at the wrist belt evaluate the objective activity level. Blood Evaluation: Lipid profile and glucose - risk factors for cardiovascular disease and metabolic syndrome. 