Associations between Plasma Folate and Vitamin B₁₂, Blood Lead, and Bone Mineral Density among Adults and Elderly Who Received a Health Examination

This study hypothesized that plasma folate and vitamin B₁₂ levels modified the association between blood lead and cadmium and total urinary arsenic levels and bone loss. A total of 447 study subjects who received a physical examination at the Wanfang Hospital Medical Center were recruited. Bone loss was defined as a calcaneus bone mineral density T-score less than −1. Blood cadmium and lead concentrations were measured by ICP-MS. Urinary arsenic species were determined using HPLC-HG-AAS. A SimulTRAC-SNB radioassay was used to measure plasma folate, vitamin B₁₂, and homocysteine levels. Total urinary arsenic and blood lead concentration were positively correlated with the odds ratio (OR) for bone loss in a dose–response manner. The OR and 95% confidence interval (CI) for bone loss in participants with blood lead concentrations > 56.14 versus ≤33.82 µg/dL were 1.82 and 1.10–3.01. No correlation between plasma folate and vitamin B₁₂ levels alone and bone loss was observed. However, this study is the first observational study to find that blood lead concentrations tend to increase the OR of bone loss in a low plasma folate and plasma vitamin B₁₂ group with multivariate ORs (95% CI) of 2.44 (0.85–6.96).