Back injuries among union carpenters in Washington State, 1989-2003.

BACKGROUND There is limited information on occupational back pain specific to carpenters despite their known exposures to recognized occupational risk factors and limited opportunities for modified work due to the predominantly heavy nature of their work. METHODS By combining union records with worker's compensation claims, we describe work-related back injuries, including associated medical diagnoses, among a well-defined cohort of union carpenters between 1989 and 2003. High risk subgroups were explored based on age, gender, union tenure, and predominant type of work. Paid lost time claims were contrasted to less serious events, and injuries sustained from overexertion activities were contrasted with those sustained through more acute trauma. RESULTS Back injuries occurred at an overall rate of 6.2/200,000 hours worked. Most injuries were coded in the compensation records as sprains, but there was little agreement between these nature of injury codes and ICD9 diagnosis codes. Injury rates declined most significantly over time for injuries secondary to overexertion. In multivariate analyses, we observed similar patterns of risk for the types of claims evaluated despite disparate mechanisms and severity. Those who worked predominantly in residential carpentry or drywall installation were consistently at greatest risk. CONCLUSIONS Overexertion injuries from manual materials handling activities are responsible for the largest burden of back injuries among these carpenters, but a growing proportion of injuries result from acute traumatic events. Interventions are called for which specifically address risk among residential carpenters and drywall installers. These data provide additional evidence that Bureau of Labor Statistics data underestimate work-related injuries.