Associations of Sleep Quality and Perceived Stress with Skin, Scalp, and Hair Health Among 1,017 Chinese Women: A Cross-Sectional Observational Study.

Background and Objective: Psychological stress and poor sleep quality are prevalent among urban adults and have been proposed to be associated with skin, scalp, and hair health through neuro-endocrine-immune pathways. However, evidence from large real-world cohorts under chronic, naturalistic conditions remains limited. The objective of this study was to characterize the associations of sleep quality and perceived stress with a range of dermatological outcomes under real-life conditions, including self-perceived concerns, expert-scored clinical signs, and objective instrumental measurement in healthy women. Methods: This cross-sectional observational study enrolled 1,017 healthy women aged 18-40 years in Shanghai, China. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and perceived stress with the Perceived Stress Scale (PSS-10). Dermatological outcomes were assessed through four modalities: validated psychometric questionnaires, self-perception surveys, expert clinical scoring, and objective instrumental measurements. Associations were investigated using generalized linear models (GLMs) adjusted for age and season (regression analytical sample: n=994 after exclusion of participants with BMI>30), with Benjamini-Hochberg correction for multiple comparisons. Results: Poor sleep quality (PSQI score ≥ 6) was identified in 60% of participants and elevated perceived stress (PSS-10 score ≥ 14) in 50%. Both factors were significantly associated with lower wellbeing, happiness, and higher fatigue scores. Poor sleep quality was associated with increased likelihood of reporting sensitive scalp (OR = 1.17 [95% CI:1.08-1.27], Adj-P = 0.004), skin fatigue appearance (OR = 1.11 [95% CI:1.06-1.17], Adj-P = 0.003), and self-perceived skin yellowness (OR = 1.10 [95% CI:1.04-1.15], Adj-P = 0.013), as well as a modest but significant increase in clinically graded dark eye circle severity (β = 0.028 [95% CI: 0.012-0.044], Adj-P = 0.014). Elevated perceived stress was associated with self-reported hair loss (OR = 1.04 [95% CI:1.01-1.06], Adj-P = 0.034) and itchy scalp (OR = 1.07 [95% CI:1.03-1.11], Adj-P = 0.035). In post-hoc exploratory age-stratified analyses, poor sleep was associated with higher acne severity exclusively in participants aged 18-25 years (p = 0.016). Conclusion: In this cross-sectional study of healthy urban women in Shanghai, poor sleep quality and elevated perceived stress were each associated with a range of self-perceived dermatological concerns and clinical signs. These findings are cross-sectional in nature and require longitudinal investigation to establish temporal directionality. The observed associations are consistent with the skin-brain axis hypothesis and support the relevance of sleep and stress assessment in dermatological research and practice.