Changes of bone mineral density in obese perimenopausal women during 5-year follow-up

The beneficial effect of obesity on bone mineral density (BMD) has not been definitely established.

The aim of the study was to evaluate changes in BMD in obese perimenopausal women during a 5-year follow-up.

The study involved 54 obese women. The group was divided into 2 subgroups according to the menopausal status: postmenopausal women--M (n = 35) and premenopausal women--P (n = 19). Laboratory tests (parathyroid hormone, 25-hydroxyvitamin D₃, C-terminal telopeptide of type I collagen, osteocalcin, and osteoprotegerin), anthropometric measurements, and densitometry were performed twice during the 5-year follow-up. The control group consisted of 19 healthy women of the same age and with normal body weight.

Obese postmenopausal women were characterized by lower BMD in the proximal femur and lumbar spine, higher fracture risk, and higher serum osteocalcin levels at baseline. During the 5-year follow-up, there was a 1.52% and 6.86% decrease in proximal femur BMD and 2.34% and 5.17% in lumbar spine BMD (in premenopausal and postmenopausal women, respectively). In postmenopausal controls, BMD reduction was 2.36% and 4.3%, respectively. In the combined analysis including all postmenopausal women, there was an inverse correlation between the initial body mass index and the changes in proximal femur BMD (r = -0.25; P <0.05) and lumbar spine BMD (r = -0.28; P = 0.08) that occurred during the 5-year follow-up.

Obesity appears not to protect against bone mineral loss in postmenopausal women.