Slipping as an upstream measure of outcome for fall-related injury research

Introduction: Falls are responsible for a substantial injury burden globally at work. A major challenge to the study falls in active work environments is the rarity of the outcome. Slipping is an important precursor to falling and subsequent injury. We applied epidemiologic methods to study individual and work environment factors related to slipping. Method: Ten limited service restaurants in the Northeastern US were recruited to participate. Workers' slip and/or fall history within the prior 4 weeks was collected along with age, gender, job tenure, weekly work hours, and shift. Shoe type, condition, and gross shoe contamination were visually assessed. Floor coefficient of friction was measured. The logistic generalized estimating equations model was used to compute adjusted odds ratios.

Results: One hundred twenty-six workers(60% female, mean age 30) participated. Multivariable logistic regression showed that higher restaurant mean coefficient of friction (COF) was significantly associated with decreased risk of self-reported slipping in the prior 4 weeks (Odds Ratio 0.59, 95% CI 0.42-0.82). From the highest to the lowest COF restaurant, the odds of slipping increased more than seven times. Younger workers, males, shorter work hours and the gross shoe contamination were also positively associated with slipping.

Conclusion: This study demonstrated that the prevalence of slipping among limited service restaurant workers was sufficiently frequent to allow the application of epidemiologic methods to assess the relative contributions of the observed exposures. Using self-reported slipping as an upstream measure of outcome may make assessment of risk factors and potential interventions for STF-related injuries more feasible.