In the present study, bone metabolism (BM) and mineralisation were investigated in Estonian women of different age. The aims were to check the reference values of BM in women by collating the data obtained from radiological investigations; to ascertain the least significant change (LSC) in the principal markers of BM. Altogether 70 healthy women who presented to the gynaecologist were studied; 38 of them were young women (YGr) aged 22–32 years and 42 were women in the peri- or postmeno-pausal period aged 44–60 years. In order to select out women with osteopenia or osteoporosis, bone mineral density (BMD) and, by quantitative ultrasound, calcaneal speed of sound (SOS) and attenuation (BUA) were determined. In addition, the combined value of SOS and BUA, i.e. stiffness index (SI), was used. The investigation of the control group of 55 women revealed the following values as the upper limits of the bone markers (confidence level 95%): urinary free desoxypyridinolin, U-DPD/Crea <15 nmol/mmol, carboxyterminal telopeptide of type I collagen, S-CTx-I < 0.70 ng/mL, bone isoenzyme of alkaline phosphatase, S-ALP-bone < 45 U/L in serum. The upper limit of serum osteocalcin, S-OC, was <50 ng/mL according to the results of YGr. In monitoring the patient, the LSC values of the principal markers were 50% of the initial value for CTx-I, 43% for DPD/Crea, 27% for ALP-bone and 40% for OC.
In addition there were two remarkable findings. Firstly, all markers in YGr were negatively correlated with age: the level was the lowest after the age of 28–29. After that age, lumbal BMD as well as calcaneal SI increased. Secondly, the intensity of BM was different in women with osteoporosis. There occurred variants from both accelerated formation and resorption processes to absence of changes in the bone markers.