Serum Calcium and Phosphorus Levels in Postmenopausal Women in a Community in Kwara State

Postmenopausal women experience accelerated bone mineral turnover due to oestrogen withdrawal, making monitoring of calcium and phosphorus homeostasis relevant for early detection of osteoporosis risk in this population. This study determines serum calcium and phosphorus levels and their relationship to bone health indicators in postmenopausal women in Ilorin, Kwara State. One hundred postmenopausal women aged between forty-five and seventy years and fifty premenopausal women of comparable age were recruited from community health centres in Ilorin. Menopause was defined as at least twelve months of amenorrhoea. Fasting blood samples were analysed for serum total calcium using the arsenazo III colorimetric method, ionized calcium by ion-selective electrode, inorganic phosphorus by the ammonium molybdate method, serum alkaline phosphatase as a bone turnover marker, and 25-hydroxyvitamin D by ELISA. Results show significantly lower serum ionized calcium and 25-hydroxyvitamin D in postmenopausal women compared to premenopausal controls. Serum inorganic phosphorus was elevated in the postmenopausal group, reflecting altered renal phosphorus handling. Alkaline phosphatase activity was significantly higher in postmenopausal women, indicating increased bone turnover. Vitamin D insufficiency, defined as 25-hydroxyvitamin D below 50 nanomoles per litre, was present in 67 percent of postmenopausal women. Duration since menopause negatively correlated with serum ionized calcium. These findings highlight the need for calcium and vitamin D supplementation programmes in postmenopausal women in Kwara State. Keywords: serum calcium, phosphorus, postmenopausal women, vitamin D, Kwara State.