Validity of self-reported exposures to work postures and manual materials handling. Stockholm MUSIC I Study Group.

TLDR

The authors validated self‑administered questionnaires on manual material handling and work postures against direct measurements and systematic observations in 97 workers across 45 occupations, testing agreement at a dichotomous level and, where possible, with quantified duration or frequency. The study found acceptable agreement for nine dichotomous posture and >5‑kg load variables, but no acceptable agreement for detailed duration or frequency scales, with musculoskeletal complaints biasing some lifting variables, indicating that self‑reported exposure may be usable only for high‑risk variables and is too crude for detailed analyses.

Abstract

Exposure data from self-administered questionnaires on manual materials handling and work postures were validated in relation to direct measurements and systematic observations on 39 men and 58 women representing 45 different occupations. The agreement was tested at a dichotomous level and, when possible, with quantification of duration or frequency. At the dichotomous level the agreement was "acceptable" for nine variables concerning work postures and the handling of loads weighing > 5 kg. No variable showed "acceptable" agreement when the duration or the frequency was quantified in more detail (4- to 6-point scales). Musculoskeletal complaints seemed to introduce a differential bias for some lifting variables. Thus some variables for postures or the handling loads of > 5 kg may, under certain conditions, be acceptable for use in epidemiologic studies when the relative risks are high. However, self-reported exposure seems to be too crude if more-detailed information is required.