Effects of consecutive night-shift work on health conditions among car-cleaners of super-express trains.

Abstract

The Shinkansen Super-Express trains of the Japanese National Railways, the so-called bullet trains, run from early morning until late at night. Accordingly the car-cleaners of the Shinkansen must do late night shift work. A self-administered questionnaire survey including items about health and work conditions was given to 246 workers at Osaka Station, who were then divided into 3 groups: Group A consisted of 102 night workers working 5 successive days with 2 days off, Group B consisted of 124 alternate-day 24-hour workers working 3 days a week, while Group C included 20 day-workers working 6 days a week. A subjective fatigue inventory was administered before and after work for a week to 20 workers selected from each of three groups, group A, B above group D whose shift was 2 times 2 successive night shifts with one day off, and one holiday a week. The results of the questionnaire survey revealed that the rates of complaints such as gastroenteric disorders and general fatigue were the highest in group A. The results of the subjective fatigue inventory show a tendency for the number of complaints in group A and B to increase significantly after the last work shift of the week, but not in the case of group D. The authors demonstrated that there was a close relationship between patterns of night-shift work and various kinds of health problems, and concluded that to insert a day off on the third day of the group D shift was effective in reducing the work load.