Temporal trend of occupational injuries; first versus second half of a working shift.

OBJECTIVES To assess occupational injuries in the 1st versus 2nd half of a working shift in terms of (a) the likelihood of hospital referral following an injury event; (b) the external causes of injuries. METHODS Logistic regression analyses of data from a 16-year (1991-2007) experience of ongoing surveillance of occupational injuries in a synthetic fiber factory in Iran. RESULTS The likelihood of a hospital referral following an injury in the 1st half of a shift was higher than in the 2nd half (adjusted odds ratio [OR] 1.50, 95% confidence interval [CI] 1.10-2.00). Comparing the 2 halves of the shift, an injury occurring in the 2nd half was more likely to be due to exposure to smoke, fire and flames (OR 2.34, 95% CI 1.06-5.19) or transport accidents (OR 1.84, 95% CI 1.06-3.21). CONCLUSIONS Time-specific safety interventions could be used in the risk management of occupational injuries. Further studies to investigate the effect of time-dependent interventions are recommended.