Effect of age and estrogen on biochemical markers of bone turnover in postmenopausal women: a population-based study from Nepal

Bashu Dev Pardhe, Sabala Pathak, Anjeela Bhetwal, Sumitra Ghimire, Shreena Shakya, Puspa Raj Khanal, Sujan Babu Marahatta Department of Laboratory Medicine, Manmohan Memorial Institute of Health Sciences, Kathmandu, Nepal Background: Osteoporosis, a common disease worldwide, is characterized by low bone mass and architectural deterioration of bone tissue, leading to enhanced bone fragility and increase in fracture risks. Both menopause and aging are related factors leading to greater risk of bone disease, particularly among postmenopausal women. Hence, the main purpose of this study was to investigate the differences in biochemical markers of bone turnover and to evaluate the association of hormones and age-related factors with biochemical markers between pre- and postmenopausal women.Methods: A descriptive cross-sectional study was conducted over a period of 6 months among the female population of Dholahity community, Lalitpur, Nepal. A total of 496 healthy women were selected based on the questionnaire strategy. Among them, 244 were premenopausal and 252 were postmenopausal women. Different bone markers were evaluated as per the guideline provided by the reagent manufacturer, and hormonal assay, particularly estradiol level assessment, was performed by chemiluminescence immunoassay-based technique.Results: A significant decrease in serum calcium level and estradiol level was observed in postmenopausal women as compared to premenopausal women, whereas a significant increase in serum phosphorus and alkaline phosphatase (ALP) levels was seen among postmenopausal (p<0.001). Age was significantly correlated with bone markers (ALP and calcium) in postmenopausal group (p<0.005), while there was no significant correlation in premenopausal group. In addition, there was significant positive correlation between calcium and estradiol in postmenopausal women, while ALP was negatively correlated with estradiol in that group. Further, no significant correlation was demonstrated between estradiol and bone markers in postmenopausal women in body mass index and age-adjusted partial correlation analysis.Conclusion: Timely diagnosis of osteoporosis in women would be of significant benefit for effective care for required populations and help to minimize mortality rate and financial burden of our country. Keywords: postmenopause, osteoporosis, bone markers, estradiol, Nepa