Effect of vitamin D and calcium levels on gender differences in bone minerals: A cross-sectional study based on NHANES 2011 to 2018

Bone health, assessed by bone mineral content (BMC) and bone mineral density (BMD), is a critical determinant of overall health and quality of life. Vitamin D and calcium are well-established factors influencing bone metabolism, but their effects may differ by gender and remain insufficiently clarified. This study aimed to examine the associations of vitamin D levels and total calcium concentrations with BMC and BMD, with a focus on gender-specific effects. Based on health data gathered from 2011 to 2018, this cross-sectional study included 11,246 participants aged ≥18 years. The study variables included BMC, BMD, 25-hydroxyvitamin D2 + D3 [25(OH)D2 + D3], 25(OH)D2, 25(OH)D3, and total calcium levels, with adjustments for covariates such as smoking, alcohol consumption, and body mass index. The associations of vitamin D and calcium with BMC and BMD were evaluated using multivariate linear regression, followed by gender-specific subgroup analyses. The results of this study disclosed that both vitamin D levels and total calcium concentrations were significantly associated with BMC and BMD (P < .05). Subgroup analysis revealed that, in males, vitamin D levels - including 25(OH)D2+ D3, 25(OH)D2, and 25(OH)D3 - were positively associated with BMC and BMD, while total calcium showed no significant effect. In contrast, among females, vitamin D levels were not significantly associated with BMC or BMD, whereas total calcium levels showed significant associations with both (P < .05). Both vitamin D and calcium are essential for bone health maintenance, and their effects differ significantly between genders. Vitamin D levels have a stronger impact on bone health in males, while calcium intake is more influential in females. This observation may inform gender-specific nutritional interventions and offers theoretical support for personalized health approaches.