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

Abstract

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

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

Patients and methods: 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.

Results: 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.

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