Advisor(s)
Jonghwa Oh
Committee Member(s)
Claudiu Lungu
Jeffrey Wickliffe
Kristine Krajnak
Mark Shall
School
School of Public Health
Document Type
Dissertation
Department (new version)
Environmental Health Sciences
Date of Award
1-7-2025
Abstract
Long-term, excessive exposure to hand-arm vibration (HAV) may induce vascular, neurological, and musculoskeletal disorders, collectively known as hand-arm vibration syndrome (HAVS). However, concerns arise when adopting the currently available guidelines and standards to protect workers who regularly use vibrating tools due to the lack of standardized exposure assessment methods for HAV and reliable health indicators for HAVS. The existing exposure-response relationship addressed in ISO 5349-1 was developed based on epidemiological studies predominantly performed in temperate zones. Thus, this dissertation aimed to evaluate the HAV exposure levels and vascular and muscular health effects from vibration exposure among groundskeepers in the southeastern US where clinical features of HAVS are less known. A 6-day observational exposure measurement study was conducted among 17 groundskeepers and 10 office workers. HAV exposure measured using vibration dosimeters and occupational exposure history obtained from a questionnaire were used to estimate the lifetime HAV exposure dose. Finger blood flowrate (FBF) was measured using laser Doppler flowmetry (LDF) and passive stiffness (PS) of the abductor pollicis brevis (APB) muscle was measured using myotonometry to evaluate vascular and muscular health effects of HAV exposure, respectively. Linear mixed models were employed to estimate the association between HAV exposure dose and FBF and between HAV exposure dose and PS, along with the study participants’ social history and health-related information obtained from a questionnaire. The groundskeepers’ lifetime HAV (i.e., 76520.6 and 61955.5 hours·m/s2 for the right and left hand, respectively) was estimated to be over 28 times higher than the office workers, with grass trimmers contributing the most to the lifetime HAV. A significant negative association between lifetime HAV and FBF was observed in the linear mixed model after adjusting for age, body mass index, race/ethnicity, and hypertension (right hand: β=-0.0006 and p-value=0.0055; left hand: β=-0.0009 and p-value=0.0068). A significant positive association between lifetime HAV and PS was observed after adjusting for age, body mass index, and race/ethnicity (right hand: β=0.0007 and p-value=0.0128; left hand: β=0.0009 and p-value=0.0108). The study findings indicated that FBF measurement and PS measurement may be a promising health indicator for the vascular and muscular disorders of HAVS, respectively, supporting the current knowledge on the pathophysiological mechanisms of HAVS. Long-term panel studies need to be followed to establish a reliable cause-effect relationship and in turn reliable standards for occupational exposure to HAV.
ProQuest ID
Recommended Citation
Chen, Nathan, "Evaluations Of Hand-Arm Vibration (Hav) Exposure And Related Vascular And Musculoskeletal Heath Effects Among Groundskeeping Workers In Southeastern U.S." (2025). All ETDs from UAB. 7308.
https://digitalcommons.library.uab.edu/etd-collection/7308
