Abstract
OBJECTIVE: Environmental pollution of heavy metals is increasingly a problem and has become of great concern due to the adverse effects it causes worldwide. Heavy metal exposure has been implicated in health problems, including fibromyalgia and rheumatoid arthritis. We aim to evaluate the rule of chronic heavy metals toxicity on the induction of vitamin D3 (VD) deficiency and parathyroid hormone (PTH) disturbances in an inflammatory disease like rheumatoid arthritis (RA) and non-inflammatory disease like fibromyalgia syndrome (FMS). METHODS: This comparative analytical study was conducted on sixty adults (age ≥ 18 years). Participants were divided into three groups. Group I: twenty patients diagnosed with RA according to the specific ACR/EULAR criteria for RA. Group II: twenty patients diagnosed with FMS according to the specific 2010 (ACR) criteria for FMS. Group III: twenty healthy adults. All patients and controls were subjected to routine laboratory tests as well as the measurement of PTH, VD and estimation of serum levels of lead, cadmium, and chromium. RESULTS: VD was significantly inversely correlated to PTH, lead, cadmium, chromium, and activity scores in the RA and FMS groups. Lead, Cadmium and Chromium had a significant independent risk on the VD level in RA patients, while lead had a significant independent risk on the VD level in FMS patients. CONCLUSION: Heavy metals may affect VD synthesis, leading to hypovitaminosis D and secondary hyperparathyroidism in RA and FMS patients. Heavy metals play a key role in the pathogenesis of RA, FMS, and their disease activity.