In aging population osteoporotic fractures in postmenopausal women are a growing problem and a cause of remarkable morbidity, individual suffering and costs. The effect of calcium and vitamin-D in fracture prevention have been tested in elderly patients mostly over 70-75 years of age and results with low dose intervention have been controversial. The aim of this study is to determine the effects of calcium (1000 mg/d) and vitamin-D (800 IU/d) in 65-71 year-old postmenopausal women in a clinical trial on two levels: a) a randomized postal interview trial (n=3432) and b) a randomized clinical trial (n=606). 5407 women of the OSTPRE-cohort received a postal enquiry with questions of health related issues and willingness to participate a calcium and vitamin-D survey. 4706 enquiries were returned. 3432 eligible women were randomised to the active treatment group (n=1718) to receive the intervention and control group (n=1714), that did not receive placebo, they were told to go on as before in terms of calcium or vitamin-D substitution. On the level of the interview trial end point variables, falls and fractures, are collected by telephone interviews annually and on the level of the clinical trial every four months. In clinically examined subset of 606 subjects axial and heel bone mineral density (BMD), heel quantitative ultrasound (QUS) measurement, anthropometric measurements, a comprehensive set of clinical (muscle strength, balance, functional capacity) and laboratory tests (serum calcium, phosphate, AFOS, creatinine, cholesterol, triglycerides, complete blood count, 25-OH-D-vitamin, PTH, osteocalcin and Trap5B and reserve, serum and urine samples) will be performed and food diary will be obtained at baseline and after 3 years follow-up and baseline blood samples will be taken for DNA-analyses.