A cross sectional study of role of health literacy on the differences in health behaviors between shift workers and day workers

Abstract Background Shift work is a common working style in the manufacturing industry. Many studies have reported that shift workers have unfavorable health behaviors. To investigate using a cross-sectional study whether health literacy had a mediating influence on the differences in health behaviors between the shift workers and day workers. Methods The target population was employees in a light metal product manufacturing company in Japan. In 2020, we conducted a survey on job characteristics, health literacy, and health behaviors using a self-administered questionnaire. A total of 2152 manual workers aged between 18-64 years were enrolled in the study (961 fixed day and 1191 shift workers). The odds ratios for favorable habits in shift workers relative to those in daytime workers were calculated using multivariate logistic regression analysis. Logistic regression structural equation models were used to analyze the mediating role of health literacy on the relationship between shift work and health behaviors. Results The odds ratios (95% confidence interval) of shift workers, with daytime workers as the reference group, following adjustment for age, health literacy, educational attainment, marital status, and working hours were 0.85 (95%CI, 0.70-1.02) for performing leisure time exercise, 0.68 (95%CI, 0.56-0.80) for not currently smoking, 0.63 (95%CI, 0.52-0.76) for brushing their teeth, 0.79 (95%CI, 0.65-0.95) for having breakfast, and 0.58 (95%CI, 0.48-0.70) for eating green and yellow vegetables. With the exception of smoking, health literacy was associated with health behaviors independent of job characteristics. The odds ratios of the direct effects of shift work on favorable habits were almost the same as the total effect. Conclusions Health literacy did not have a mediating influence on the association between the shift work and health behaviors in manual workers. Both job characteristics and Health literacy were related independently with health behaviors in the workers. Our findings suggest that in order to improve health behaviors in workers, both improvement in the working environment and efforts to improve Health literacy are required.