Different involutionary changes in bone mineral density with age in three skeletal sites in healthy Polish women

The aim of the study was to estimate the differences in bone mineral density (BMD) at three skeletal sites, with regard to age and menopausal status.The study was conducted between 2001 and 2006 in the Polish city of Wroc?aw and the sample was comprised of 440 healthy female inhabitants aged 40–88 years. The measurements of bone mineral density were taken at three sites: femoral neck, Ward's triangle and trochanter major. Two bone mineral density characteristics were used in further analysis: absolute measure of bone mineral density (BMD) expressed in g/(100 mm)², and % of BMD of the peak value calculated for young adults (20–45, USA reference population). Pre- and postmenopausal status was defined according to occurrence of menstruation within the last 60 days.The changes in bone mineral density with age showed significantly different patterns in different skeletal sites. While the decrease in bone mineral density in the femoral neck and Ward's triangle were parallel and gradual, the changes in trochanter major were very small and between the age groups 51–55 and 71–75, nearly unnoticeable. A comparison between pre- and postmenopausal women aged 46–55, showed a significant effect of menopausal status. The average bone mineral densities in the three skeletal sites were higher in premenopausal than in postmenopausal women. The highest value of bone mineral density was found in the femoral neck, significantly lower in Ward's triangle, and a little lower (non-significantly) in the trochanter major than in the Ward's triangle. Postmenopausal women had a little higher BMD value in the trochanter major than in the Ward's triangle site.