LAUSR

Introduction Past research finds that both male and female workers in male-dominated workplaces experience decreased job satisfaction and increased work-related stress. Female workers in particular are more likely to experience gender discrimination, sexual harassment, and social isolation. Nevertheless, systematic evidence regarding the association between workplace gender composition and worker mental healthcare utilization remains limited. Methods Using data from the American Manufacturing Cohort Study (AMC), we examined the association between workplace gender composition and risk of depression-related outpatient visits among hourly workers employed at one of 32 U.S. aluminum plants between 2003 - 2013.Using generalized additive models (GAM) with a logit link, we modeled risk of depression-related outpatient visits as a function of annual workplace gender composition (i.e. percent women) and covariates (baseline age, race, sex, plant, and calendar year). We captured potential nonlinear relationships using cubic smoothing splines. We used g-computation to summarize the counterfactual risk of depression-related outpatient visits under three hypothetical interventions wherein women comprised at least 10, 20, or 30 percent of the workforce at all plants for all years of follow-up. We compared these counterfactual risks to the risk under no intervention (the observed data). Results Across all 32 U.S. plants, the final study sample included 5,279 female and 24,124 male hourly workers. We observed significant reductions in the number of depression-related outpatient visits when women comprised at least 20% (RD=-6.2, 95% CI -8.75, -3.65) and 30% (-14.6; 95% CI -19.0, -10.2) of the workforce. Findings were consistent within subgroups of male and female workers. Conclusion The gender composition of industries, occupations, and workplaces is an important expression of social structure. We find that modest increases in the percent women employed in otherwise male-dominated work environments can lead to measurable reductions in the frequency of depression-related outpatient visits among male and female hourly workers.