[Risk factors for low back pain among taxi drivers in Japan]

We conducted a questionnaire study on low back pain (LBP) and working conditions among male taxi drivers employed in the company in Fukuoka city in order to investigate the occurrence of LBP and occupational factors related to LBP among taxi drivers. The study was undertaken through two questionnaires, the first conducted in 1999 (n = 280, first cross-sectional study), the second conducted in 2001 (n = 284, second cross-sectional study). The questionnaire results were used to conduct two analyses: 1) the one-year prevalence of LBP and the relationship between LBP and occupational factors in the second cross-sectional study, and 2) the incidence of LBP and the relationship between LBP and occupational factors from the first to the second cross-sectional study in the longitudinal study. The incidence cases were defined as subjects who met the following conditions: those who had never experienced LBP at the time of the first study but had experienced LBP during the previous year at the time of the 2nd study. The one-year prevalence (45.8%) of LBP among taxi drivers was comparable to rates reported for other occupational drivers in which LBP occurs frequently. This result indicates that LBP is an important health problem for taxi drivers, and an urgent occupational safety and health management issue. The two-year incidence of LBP among the taxi drivers was estimated at 25.9%. LBP was significantly related with the suitability of the driver's seat pan, total mileage on the taxi (total mileage), the level of uncomfortable vibrations on the road, job stress and time employed as a taxi driver. Importantly, the prevalence of LBP increased with increasing total mileage, a finding which had not previously been reported. The findings of this study also suggest that ergonomic problems with the driver's seat pan, whole-body vibration (WBV) and job stress may contribute to LBP among taxi drivers. Further study is needed to confirm how total mileage contributes to LBP. Furthermore, WBV during normal use of taxies should be measured in order to evaluate the association between WBV and LBP.