Risk indicators of low back pain among workers in Japan. Association of familial and physical factors with low back pain.

STUDY DESIGN

A questionnaire was given to 3,042 Japanese workers at a factory in 1992. It surveyed age, gender, weight, height, job classification, and work environment, as well as the perceived causes, onset age, and characteristics of low back pain. Family history of low back pain among first-degree relatives and perception of physical condition also were assessed.

OBJECTIVES

To investigate the risk indicators of low back pain in Japanese workers with various kinds of job classifications in a manufacturing company.

SUMMARY OF BACKGROUND DATA

Risk indicators of low back pain in Japanese patients have not been fully investigated in previous studies.

METHODS

Prevalence rates and characteristics of low back pain were examined among 3,042 factory workers (2,517 men and 525 woman) with jobs with varying physical demands. In the analysis of risk indicators of low back pain, the odds ratios and 95% confidence intervals were computed. In addition, a multiple logistic analysis was performed to evaluate risk indicators of low back pain.

RESULTS

Point and lifetime prevalence of low back pain were correlated with the physical demands of the job. The perceived cause found to be most associated with low back pain were lifting in workers with jobs requiring moderate to heavy work and sports activity in sedentary workers. Family history of low back pain in parents, siblings, and children was a risk indicator of low back pain. The average age of the first attack of low back pain in workers with a family history of it in their parents was significantly younger than that in workers with no family history in a multiple logistic analysis in male workers, the physical work demands, age, and family history of low back pain in their parents were risk indicators; however, obesity was not a risk indicator. Physical and mental conditions of workers also were associated with low back pain.

CONCLUSIONS

The physical job demands show a clear association with the point and lifetime prevalence of low back pain, and improvements in work conditions may decrease low back symptoms among workers. It is likely that a family history of low back pain and physical and mental conditions of workers also should be considered in the management of low back pain.