Serum 25(OH) vitamin D deficiency among young adults in the East Khasi Hills district of Meghalaya and its influence on bone mineral density: Investigating the involvement of the RANKL/RANK/OPG system

ABSTRACT Vitamin D’s precise role in bone mineral density regulation remains elusive. Nevertheless, its deficiency is linked to increased bone turnover through the upregulation of RANK ligands by osteoblasts. This study aimed to (i) evaluate vitamin D status in young adults and (ii) assess the association between vitamin D deficiency and bone turnover markers receptor activator of nuclear factor-κB ligand (RANKL), RANK, and the osteoprotegerin (OPG) in determining bone mineral density. This cross-sectional study involved 474 participants from the East Khasi Hills district, Meghalaya. Vitamin D levels were measured using the UniCel DxI 800 system, while OPG, RANK, and RANKL were assessed through enzyme-linked immunosorbent assay (ELISA). Additionally, a whole-body dual X-ray absorptiometry (DEXA) scan determined bone mineral density. Vitamin D deficiency was categorised as <20 ng/ml, insufficiency as 20–29 ng/ml, and sufficiency as ≥30 ng/ml. Findings indicated 54.6% vitamin D deficiency and 35.4% insufficiency in young adults. Osteoporosis affected 26%, and 67% exhibited osteopenia. A weak positive correlation was found between vitamin 25(OH) D and bone mineral density T score (r = 0.16, r2 = 0.02, P = 0.44). Additionally, moderately weak correlations were observed between serum vitamin D and OPG (r = –0.42, r2 = 0.18, P < 0.001) and between vitamin D and RANKL (r = –0.13, r2 = 0.01, P = 0.18). The study suggests that vitamin D deficiency diminishes bone mineral density by promoting RANKL-RANK osteoclastogenesis and upregulating OPG expression. As young adults form a significant workforce, creating awareness is crucial for maintaining optimal health.