Reliability and Validity of an Adapted Questionnaire Assessing Occupational Exposures to Hazardous Chemicals among Health Care Workers in Bhutan

Background: The major portion of lead in the body resides in skeletal system. The bone turnover affects the release of lead into the circulation from bones. The bone turnover biomarkers (BTM) in lead-battery workers with long-term exposure to lead have not been explored yet. Objective: To evaluate the BTM (formation and resorption) in lead-battery workers with long-term exposure to lead in lead-battery manufacturing plant. Methods: 176 male lead-exposed workers and 80 matched comparison group were studied. All participants were examined for blood lead levels (BLLs), bone formation biomarkers— serum osteocalcin (OC), alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BALP)—and bone resorption biomarkers—serum pyridinoline (PYD), deoxypyridinoline (DPYD), tartarate-resistant acid phosphatase-5b (TRACP-5b), and urinary hydroxyproline (UHYP). Results: We found a significantly higher bone formation biomarkers such as BALP (p=0.007) and bone resorption biomarkers, eg, PYD (p=0.048), TRCAP-5b (p=0.001), and UHYP (p=0.001) in lead-exposed workers. A significant (p=0.041) negative correlation (ρ ‑0.128) was noted between BLLs and OC. A significant positive correlation was noted between BLLs and TRACP-5b (ρ 0.176, p=0.005) and UHYP (ρ 0.258, p=0.004). Serum OC (p=0.040) and UHYP (p=0.015) levels changed significantly with BLL level. Bone resorption biomarkers levels— PYD, TRACP-5b, and BALP—were higher among those with higher BLLs levels. The duration of exposure was significantly associated with BALP (p=0.037), DPYD (p=0.016), TRACP-5b (p=0.001), and UHYP (p=0.002) levels. Conclusion: Long-term lead exposure affects the bone turnover