Back disorders and nonneutral trunk postures of automobile assembly workers.

TLDR

The study evaluated the health impact of nonneutral trunk postures, such as bending and twisting, among automobile assembly workers. Using a case‑referent design, 95 back‑pain cases and 124 pain‑free referents were selected, and their job tasks were analyzed for postural and lifting demands with video recording and software analysis by blinded analysts. Back disorders were significantly associated with mild trunk flexion (OR 4.9), severe trunk flexion (OR 5.7), and trunk twist or lateral bend (OR 5.9), with risk rising with multiple postures and longer exposure duration.

Abstract

A case-referent study was conducted in an automobile assembly plant to evaluate the health effect of trunk postures, such as bending and twisting, that deviate from anatomically neutral. Cases of back disorders were all those of workers who reported back pain to the medical department in a ten-month period and met the severity criteria of an interview. The referents were randomly selected workers free of back pain according to medical department records, an interview, and an examination. For each of the final 95 cases and 124 referents, the job was analyzed for postural and lifting requirements with a video recording and software analysis system by analysts blinded to the case/referent status. Back disorders were associated with mild trunk flexion [odds ratio (OR) 4.9, 95% confidence interval (95% CI) 1.4-17.4], severe trunk flexion (OR 5.7, 95% CI 1.6-20.4), and trunk twist or lateral bend (OR 5.9, 95% CI 1.6-21.4). The risk increased with exposure to multiple postures and increasing duration of exposure.