Lumbar and femoral bone density in perimenopausal women with irregular cycles.

Objective ― The aim of the study was to evaluate the impact of irregular cycles on bone mass in perimenopausal women. Setting - University clinic. Patients and Methods - 118 healthy women aged between 45 and 55 years were divided into three groups according to the previous year's menstrual history (pre-menopause: regular cycles; perimenopause: irregular cycles; early postmenopause: 1-3 years since the last menstrual cycle). Among the perimenopausal group, only women presenting intervals without menstruation longer than 3 months during the year of the study were selected. Bone mineral density of the lumbar spine and of the proximal femur was measured by dual energy X-ray absorptiometry (DEXA) at the start of the study and after 12 months. Results - The serum estradiol level was significantly lower in postmenopausal women and the FSH serum level showed a significant increase in perimenopausal and postmenopausal women in comparison with premenopausal controls. Bone density at L 2 -L 4 , femoral neck, greater trochanter, and total femur did not show significant differences at the beginning of the between-group study. Only the density in Ward's triangle was significantly lower in perimenopausal and postmenopausal women. After twelve months the densities of L 2 -L 4 , greater trochanter, Ward's triangle, and total femur showed a significant decrease in postmenopausal women in comparison. The perimenopausal group showed a significant decrease in total femur and Ward's triangle density in comparison with premenopausal. Conclusion - The occurrence of marked irregularity of menstrual cycles preceding menopause can influence bone mass, in particular at the femoral site.