Introduction While there is a body of literature that identifies relations between injury occurrence and resulting depression, literature relevant to a relation between work factors and depression and injury occurrence is limited.

Objectives To identify the potential relations between: 1) work-related factors and depression diagnosis and 2) depression diagnosis and injury outcome and consequences in a high-risk, understudied population.

Methods Specially designed questionnaires were disseminated to 1,200 full-time janitors in the SEIU Local 26 union to collect information on their injury occurrences, personal characteristics, health history, and work-related exposures, for two sequential six-month periods. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using multivariable Poisson regression with robust error variances, and included bias adjustment for non-response and adjustment for within-person correlation using general estimating equations (GEEs).

Results A total of 527 observations among 390 janitors identified associations between work environment factors (range = 1, terrible/unhappy/mostly dissatisfied; 2, mixed feelings; 3, mostly satisfied/pleased delighted) and diagnosed depression (n=48): how they felt about people they worked with (1 versus [vs] 3 - RR 3.86; CI 1.31, 11.36); how they felt about the work itself (2 vs 3 - RR 2.54; CI 1.36, 4.77); resources available for their job (1 vs 3 - RR 2.93; CI 1.27, 6.75). Associations were also identified between high (4,5 very much, often) vs low (1–3 sometimes, very little, not at all) frequency of stress and depression (RR 4.79; CI 2.22, 10.36) and between depression diagnosis and risk of injury-related persistent problems (RR 5.19; CI 1.40, 19.24).

Conclusions This analysis enabled identification of work-related factors associated with diagnosed depression, the relation between stress and depression, and the risk of injury and consequences among those with depression. These findings serve as a basis for future research and relevant interventions to facilitate optimal working environments.