Extended work hours and risk of acute occupational injury: A case-crossover study of workers in manufacturing

Abstract

Objective: This study was designed to determine whether injury risk among manufacturing workers was related to hours worked during the previous week.

Methods: A case-crossover design was utilized to contrast hours worked prior to an injury shift with those worked prior to a non-injury shift for hourly workers. Paired t-tests were used to determine significance of the difference. Conditional logistic regression was used to assess dose-response.

Results: Hours worked prior to injury significantly exceeded hours during the control week. Workers who worked more than 64 hr in the week before the shift had an 88% excess risk compared to those who worked 40 hr or fewer, P < 0.05.

Conclusion: The study provides evidence that injury risk is related to time worked during the previous week. Control of overtime in manufacturing may reduce risk of worker injury.