Causal analysis of back belts to prevent low back pain.
Proc Am Stat Assoc Sect Stat Epidemiology. Alexandria, VA: American Statistical Association, 2002 Mar; :1-6
In a prospective study of the effect of back belts to prevent low back pain, 4,203 material handlers, who did not report a history of previous back pain in a baseline telephone interview, completed a 6-month follow up telephone interview. Belt wearing was self-determined, but influenced by store policy, for which there was poor compliance. Classification tree methods were used to define ten groups of workers with similar propensity to wear back belts. The effect of self-reported belt wearing on self-reported incident low back pain was evaluated within these ten strata. Stratum specific risk differences, odds ratios and logistic regression estimates of the effects of back belts were used to calculate weighted estimates and weighted estimates of variance. There was little evidence to suggest any lack of homogeneity of the effects of belt wearing across strata. Given this propensity stratum adjustment for nonrandom treatment assignment, there was no difference in the incidence of low back pain between those who reported wearing back belts "usually everyday" and those who reported "never" to a question about belt wearing habits.
Back-injuries; Injury-prevention; Injuries; Risk-analysis; Risk-factors; Workers; Epidemiology
Division of Safety Research, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, 1095 Willowdale Road, MS/1811, Morgantown, WV 26505
Disease and Injury: Low Back Disorders; Research Tools and Approaches: Intervention Effectiveness Research
Proceedings of the American Statistical Association, Section on Statistics in Epidemiology