Exploring the influencing factors on acne, melasma, and rosacea: A case-control study in China.

Background: The severity and treatment response of acne, melasma, and rosacea may be influenced by various currently unclear internal and external factors. This study aimed to provide evidence to the influencing factors for the mentioned conditions through a real-world case-control study.

Methods: An online survey consisting of 60 questions was implemented, collecting information on demographics, socioeconomics, genetic factors, lifestyle habits, environmental exposures, and skin care behaviors. Then we constructed univariate and multivariate logistic regressions. Furthermore, we analyzed the dose-response relationship between exposure and outcome.

Results: A total of 399 individuals, including 94 acne patients, 107 melasma patients, and 91 rosacea patients were included. Acne and melasma were positively correlated with screen time (acne: odds ratio [OR]: 2.24, 95% confidence interval [CI]: 1.25-4.02; melasma: OR: 1.59, 95% CI: 1.09-2.31), while exercise exerted a protective effect on both acne (OR: 0.31, 95% CI: 0.13-0.77) and melasma (OR: 0.42, 95% CI: 0.22-0.80) in a dose-response relationship. In addition, males were associated with an elevated risk of acne (OR: 6.62, 95% CI: 1.01-43.26). Aging (OR: 1.15, 95% CI: 1.07-1.24) and irregular bowel movements (OR: 2.99, 95% CI: 1.11-8.08) were independent risk factors for melasma. Rosacea was positively associated with BMI (OR: 1.17, 95% CI: 1.01-1.35).

Conclusion: In our study, we highlighted exercise as an independent protective factor for both acne and melasma in a dose-response trend. Inversely, extended use of electronic equipment was independently associated with higher risks of acne and melasma. Rosacea, however, was more likely to be related with BMI.