Comparison of occupational exposure methods relevant to musculoskeletal disorders: worker-workstation interaction in an office environment

Work related musculoskeletal disorders have been associated with office work yet exposure quantification is challenging and not measured consistently. Our objective was to examine associations within and across exposure measurements guided by a conceptual model of three measurement locations: external to the body, at the interface, and internal to the body. Forty-one office workers (71% female), mean age 41years (SD=9.6), mean height 168cm (SD=10.3), and mean weight 74kg (SD=19), were recruited from a large urban newspaper. Four methods of quantifying mechanical exposure were used linked to locations: equipment dimensions (external), relative fit and postures (interface), and EMG (internal). We explored: (1) a within-location analysis of relationships among methods; and (2) a cross-location analysis of relationships among methods. Exposure method comparisons showed mostly weak correlations among equipment variables, moderate correlations among posture variables, and strong or moderate correlations among EMG variables. For the majority of pair-wise comparisons between exposure measures across locations, the correlations were weak or moderate. Comparisons of relative fit revealed some differences in dimensions, postures, and EMG measures. Few strong associations between various exposure measures were found, although worker-reported relative fit holds promise. Future work might link exposure methods (specific measures) with locations for particular purposes