The Metabolic Architecture of Bone Health: Vitamin D, Adiposity, and DXA-Derived Skeletal Phenotypes

Abstract

Background: Vitamin D is essential for calcium absorption, skeletal mineralization, and musculoskeletal health. However, the relationship between serum 25-Hydroxyvitamin D [25(OH) D], Body Mass Index (BMI), and DEXA-defined osteopenia or osteoporosis remains debated, particularly in populations with heterogeneous nutritional, lifestyle, and clinical risk factors.

Objective: This study evaluated the distribution of vitamin D status and Bone Mineral Density (BMD) categories and examined whether vitamin D and BMI were associated with osteopenia or osteoporosis in a diagnostic-center population in Pakistan.

Methods: A cross-sectional analysis was conducted among individuals evaluated at Islamabad Diagnostic Center, Islamabad, Pakistan, from January 2020 to March 2025. Serum 25(OH)D testing and Dual-Energy X-ray Absorptiometry (DEXA) or BMD assessment were reviewed. BMD categories were summarized for the lumbar spine, hip joint, and forearm. Vitamin D status was categorized as normal, insufficient, deficient, or high. Pearson correlation was used to evaluate associations between vitamin D, BMI, and bone health categories.

Results: A total of 2,202 individuals had vitamin D data. Normal vitamin D levels were reported in 1,579 (72%), insufficiency in 328 (15%), deficiency in 265 (12%), and high levels in 30 (1%). Across DEXA anatomical readings, 806 were normal, 868 were osteopenic, and 382 were osteoporotic. Osteoporosis was most frequent in the forearm, while osteopenia was common across lumbar spine and hip readings. Vitamin D showed no significant correlation with osteopenia (r=0.02, p=0.68) or osteoporosis (r=-0.03, p=0.56). BMI also showed no significant correlation with osteopenia (r= 0.01, p=0.77) or osteoporosis (r=0.04, p=0.44).

Conclusion: In this cohort, serum vitamin D and BMI were not reliable standalone predictors of DEXA-defined osteopenia or osteoporosis. Bone health assessment should integrate DEXA findings, age, sex, fracture history, hormonal status, medication exposure, nutrition, physical activity, and other clinical risk factors.

Keywords: Vitamin D; 25-Hydroxyvitamin D; Body Mass Index; Osteopenia; Osteoporosis; DEXA; Bone Mineral Density

Citation

Rehan Uppal M, Saeed U, Uppal R, Saad Uppal M, Zahid Piracha Z. The Metabolic Architecture of Bone Health: Vitamin D, Adiposity, and DXA-Derived Skeletal Phenotypes. WebLog J Nutr Food Sci. wjnfs.2026.h2906. https://doi.org/10.5281/zenodo.22513678