Epidemiological Risk Factors Associated with Acne Vulgaris Presentation, Severity, and Scarring in a Singapore Chinese Population: A Cross-Sectional Study.

Background: Acne vulgaris is classified based on the severity of skin lesions and post-healing scar types of these lesions. Numerous epidemiology studies have investigated the risk factors associated with acne presentation and severity, but studies for acne scarring are lacking.

Objective: To investigate the prevalence of acne, severity, and scarring grades and their associated risk factors among Singapore Chinese.

Methods: A total of 3,888 subjects (2,090 cases/1,798 controls; median age = 21 ± 4.589; range 17-71) completed an investigator-administered questionnaire as part of a cross-sectional study, which included sociodemographics, familial medical history, lifestyle factors, dietary habits, and acne history. Acne cases were further evaluated for their severity (n = 991) and scarring (n = 988) grades by a trained personnel.

Results: The majority of the acne cases had mild acne/grade 1 scarring, while less than 1% had severe acne/grade 4 scarring. Parental acne was significantly associated with acne presentation and moderate/severe acne, while sibling acne was significantly associated with grade 3/4 scarring. Gender and age affected acne severity and scarring but not acne presentation, while tertiary maternal education level and the possession of ≥3 siblings were particularly associated with acne scarring. Underweight BMI was protective against acne presentation, while atopic diseases (asthma, allergic rhinitis, eczema) were its predisposing factors. Of the evaluated lifestyle factors, computer/TV usage had significant association with acne presentation, while alcohol consumption was significantly associated with acne severity. Frequent milk consumption was associated with a protective effect for moderate-severe acne, while frequent butter consumption had a detrimental effect on acne scarring extent.

Conclusion: Positive familial history is a strong predisposing factor in determining acne presentation, severity, and scarring. Demographic factors (gender, age) and sedentary lifestyle (increased computer/TV usage) influence acne presentation, while dietary habits (milk and butter consumption) influence acne severity and scarring. The predisposing factors revealed in this study could help us to gain insights into acne pathophysiology and hence develop interventions especially targeting modifiable risk factors.