The effects of aging and parathyroid hormone on bone density

Abstract

Background: Osteoporosis is characterized by chronic and progressive alterations in bone microstructure, leads to reduced bone density and increased fracture risk. The incidence of osteoporosis and related fractures are rising due to increased life expectancy and evolving lifestyles globally. Researchers have explored osteoporosis prevalence and associated risk factors, including hormones, minerals, and genetics via cross-sectional and case-control study designs in our country. No research work has been conducted to ascertain the long-term changes in bone density and the factors influencing them. Aim: To evaluate changes in the bone density of the study participants after 10 years and identify associated factors. Materials and Methods: This prospective cohort study was conducted at the Department of Pathophysiology, School of Biomedicine, MNUMS. We have re-enrolled 151 adults from Ulaanbaatar between November 2023 and January 2024, originally part of the ‘Study of some risk and pathophysiological factors of osteoporosis in the Mongolian population’ funded by the Ministry of Health and the Science and Technology Fund of Mongolia. Data collection included questionnaires, anthropometric measurements, bone mineral density assessments using the ‘Sunlight Mini-Omni’ bone sonometer (Beammed, USA), and measurement of serum parathyroid hormone levels. Results: The average age of participants was 56.3±10.93 (N=151), with 29.1% (n=44) male and 70.9% (n=107) female. The mean T-score of bone density in 2014 was -0.18±1.81, after 10 years, it decreased to -2.11±1.51. (p<0.01) Menopause (RR=2.9, 95% CI 1.201-6.762), postmenopause up to 5 years (RR=3.0, 95% CI 1.126 - 7.993), and postmenopause 5-10 years (RR=2.8, 95% CI 1.14 - 6.808) were associated with an increased risk of osteoporosis (p<0.05). A height reduction of more than 1 cm compared to participants without reduction had RR=3.0 [95% CI 1.138-7.981] (p<0.05). No significant correlation was observed between bone density parameters and serum parathyroid hormone (r=-0.024, p<0.05). Conclusions: Over the course of a decade, the bone density of the study participants demonstrated a discernible decline correlating with advancing age. Notably, age-related factors exerted a more pronounced influence on bone density than mineral metabolism.