Association between Musculoskeletal Pain and Bone Turnover Markers in Long-Term Pb-Exposed Workers

Background: On chronic exposure, Lead (Pb) deposits in the skeletal system, replaces calciumions, and alters the normal physiological processes, which in turn, lead to stunting, delayed fracturehealing, and high resorption of collagen molecules. The present study aimed to assess theassociation of musculoskeletal pain and discomfort with bone turnover markers (BTMs) amonglong-term Pb-exposed workers.Study design: A cross-sectional study.Methods: The study recruited ۱۷۶ male Pb-exposed workers and ۸۰ control subjects who werematched for age, gender, and socio-economic status. Blood lead levels (BLLs), bone growthmarkers, such as serum osteocalcin (OC), alkaline phosphatase (ALP), bone alkaline phosphatase(BAP), and bone resorption markers: serum pyridinoline (Pry), deoxypyridinoline (DPry), tartrateresistantacid phosphatase-۵b(TRACP-۵b), and hydroxyproline in urine (HyP-U) of participantswere investigated. Pain and discomfort in the musculoskeletal system were assessed using NordicMusculoskeletal Questionnaire.Results: Pb-exposure was significantly associated with musculoskeletal discomfort of the lowerback (P<۰.۰۰۱), upper back (P<۰.۰۰۱), and ankle/foot (P=۰.۰۱۱). Among bone formation markers,serum OC was significantly lower in musculoskeletal discomfort of elbows (P=۰.۰۳۳) and ankle/foot(P=۰.۰۴۲). Among bone resorption markers, serum DPry was significantly lower in musculoskeletaldiscomfort of the neck (P=۰.۰۴۹) and shoulders (P=۰.۰۲۳). HyP-U was significantly higher inmusculoskeletal discomfort of shoulders (P=۰.۰۳۵) and lower back (P=۰.۰۳۶).Conclusion: As evidenced by the obtained results, Pb-exposure was associated withmusculoskeletal discomfort of the lower back, upper back, and ankle/foot. Lower bone formation(serum OC) marker was noted with musculoskeletal discomfort of elbows and ankle/foot.Furthermore, bone resorption markers were associated with musculoskeletal discomfort of theneck, shoulders, and lower back. The findings of the present study suggested that long-term Pbexposureand BTMs were associated with musculoskeletal discomfort.

Keywords:

Musculoskeletal pain , Bone remodeling , Bone formation , Bone resorption , Lead , Blood , Occupational exposure