Association of Urinary Calcium and Phosphate with Bone Mineral Density among Postmenopausal Women

Introduction: Development of peak bone mass and premenopausal bone loss is determined by the menstrual status of a women. Objective of this study was to determine the association of urinary calcium and phosphate with bone loss in post-menopausal women. This study is cross sectional. It was carried out in the Department of Biochemistry, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. Method: Females (n = 90) were assessed with measurements of Body Mass Index, 24 hour urinary excretion of calcium creatinine ratio, Phosphate creatinine ratio. Bone mineral density of women was evaluated by Dual Energy X-ray Absorptiometrey (DEXA) and its association was analyzed with urinary calcium creatinine ratio and urinary phosphate creatinine ratio. Results: Twenty two (44%) postmenopausal women were found to be osteoporotic while 24 (48%) were osteopenic on the basis of BMD measurements. The mean urinary calcium creatinine ratio and phosphate creatinine ratio was increased in postmenopausal women compared to pre-menopausal women (p < 0.001). A significant negative correlation was found between BMD (hip) and urinary calcium and phosphate (r = – 0.65, p < 0.05) (r = 0.58, p < 0.01) respectively in post-menopausal osteoporotic women. Conclusion: Urinary calcium and phosphate creatinine ratio appears to be a valuable markers for assessing bone loss in postmenopausal women.