[Subjective pain and tenderness in low back among care workers in relation to work load and daily life]

Five hundred and fifty-two care-workers aged 20 to 60 years, who worked at six custodial-care homes, were examined to clarify the relationship between subjective pain and tenderness in the low back, together with the factors affecting occupational low back pain. Subjects who were diagnosed as having tenderness in the low back by one medical practitioner at the time of health examinations, and those who reported the presence of low back pain in self-rating questionnaires were defined as those with "objective" and "subjective" low back pain, respectively. Complaints concerning workloads and daily life, as well as musculoskeletal and systemic symptoms, were inquired of in the self-rating questionnaires; the former complaints were compiled into four factors representing "environmental load at work," "physical load at work," "mental load at work," and "daily life" by the factor analysis. The corresponding rates in subjective and objective low back pains were 67.0% in 188 male care workers and 70.9% in 364 female care workers. In males and females, "physical load at work" was positively related to subjective low back pain (P < 0.05) with the use of the multiple logistic regression analysis including all the causal and confounding factors. Musculoskeletal symptoms in females were also positively related to subjective and objective low back pain (P < 0.05). These data suggest that subjective low back pain clearly reflects the problem of occupational low back pain as a whole, and that low back pain is mainly related to the physical load at work in care workers.