Mediating Effect of Sleep Quality on the Association Between Psychological Stress and Acne Vulgaris in Chinese College Students: A Cross-Sectional Study

Objective: To identify modifiable factors associated with acne vulgaris in college students and further delineate the potential mechanistic pathway underlying the effect of psychological stress on acne development. Methods: We conducted a cross-sectional study with a questionnaire-based survey among 819 college students, collecting data on demographic characteristics, lifestyle behaviors, sleep quality, psychological stress, and acne prevalence. Descriptive statistics and univariate analyses were used to compare baseline characteristics between groups, and stepwise adjusted binary logistic regression models were constructed to identify independent risk factors for acne. The Bootstrap method was applied for mediation effect analysis. Subgroup analyses, interaction tests, sensitivity analyses, and robustness analyses were also performed. Results: The overall prevalence of acne in the study cohort was 33.33%. Multivariable regression analysis revealed that total stress score (OR = 1.187, p < 0.001), poor sleep quality (OR = 1.109, p = 0.010), excessive screen time (OR = 1.107, p = 0.021), intake of sugary drinks (OR = 1.561, p = 0.027), spicy diet (OR = 1.739, p = 0.003), smoking (OR = 1.809, p = 0.031), and use of skincare products (OR = 2.004, p = 0.001) were independent risk factors for acne, while outdoor activities were a protective factor (OR = 0.676, p = 0.048). Mediation effect analysis demonstrated that psychological stress exerted not only a direct effect on acne development, but also an indirect effect to increase disease risk via impairing sleep quality. This indirect effect was statistically significant (95% CI: 0.000–0.013, p < 0.05), accounting for approximately 20.67% of the total effect. The sensitivity analysis revealed that the E-values of all significant variables were greater than 1.4. The robustness test indicated that the results remained unchanged after excluding students majoring in medicine and extreme values. Furthermore, LASSO variable screening and Bootstrap internal validation further verified the stability of the model. Conclusions: Although as a cross-sectional study, this work cannot establish causal relationships, but we found that psychological stress and sleep disturbance are key modifiable risk factors for acne, and the impact of stress on acne is partially mediated by the impairment of sleep quality.