Biochemical predictors of bone mineral density and fracture susceptibility in Maltese postmenopausal women

Abstract

INTRODUCTION: Osteoporosis and fractures are complex skeletal conditions resulting from an interplay of genetic and environmental factors. The aim of the study was to investigate the association of biochemical levels of total serum calcium, total serum alkaline phosphatase (sALP) and serum albumin with bone mineral density (BMD) levels at the lumbar spine (LS) and femoral neck (FN), and with fracture risk in Maltese postmenopausal women. Levels were also correlated with age, years since menopause (YSM) and physical activity.

METHODS: A case-control study of 1045 women was performed. Women who suffered a fracture were classified as cases whereas women without a fracture history were included as controls subdivided into normal, osteopenic or osteoporotic according to their BMD measurements. Blood specimens were collected following good standard practice and testing was performed by spectrophotometry.

RESULTS: Calcium, and to a lower extent sALP, were correlated with FN BMD levels. Fracture cases, especially those who sustained a hip fracture, had the lowest levels of calcium, sALP and albumin relative to all other control groups. Biochemical levels decreased with increasing age, possibly increasing fracture risk. YSM was correlated with lower calcium levels in fracture cases (rho: 0.229, P<O.01). Biochemical levels significantly decreased with reduced physical activity in fracture cases. Moreover, reduced physical activity was associated with decreased BMD levels at the hip and spine.

CONCLUSION: Results suggest that levels of calcium, sALP and albumin could be indicative of fracture risk, whereas calcium levels and to lower extent sALP are indicators of hip BMD.