A case-control study of risk factors for industrial low back injury: implications for primary and secondary prevention programs.

Data were collected on 228 consecutive back injuries in Boston's General Mail Facility and 228 non-injured controls drawn randomly from each case's work unit, matching on craft (clerk, mailhandler, maintenance), shift, and general supervisor. Data were collected on age, gender, duration of employment, 3 year history of injury claims, overtime work in the past 2 weeks, job change in the past 60 days, and machine vs. manual job. Risk factors for back injury were examined simultaneously in a conditional logistic regression for matched pairs. Risk factors included history of back injury claim (OR = 16.5, p less than 0.0001), younger age (OR = 3.0, p = 0.0001), shorter duration of employment (OR = 2.6, p = 0.0007), recent job change (OR = 2.5, p = 0.06), and history of non-back injury claim (OR = 2.0, p = 0.08). Among heavy lifters (vs. clerks) overtime and being female increased the risk of injury. In this setting, higher risk workers who may benefit from preventive education programs can be identified.