INTRODUCTION
Identical twins are a unique population of subjects given their similar genetic makeup. Looking at concordant and nonconcordant identical twin pairs can separate genetic and environmental effects of a disease process. Concordant pairs each have the phenotype for a given disease. In nonconcordant pairs, one twin has the phenotype and one does not. The Twins Day Festival in Twinsburg, Ohio is the largest annual gathering of multiples and is an ideal setting for conducting research in twins. Studying twins, Bataille et al found that roughly 80% of the variance of acne disease is attributable to additive genetic effects and the remaining, roughly 20%, is due to unique, unshared environmental factors.1 Environmental factors contributing to acne may include stress,2 milk chocolate consumption,3 low intake of fruits and vegetables,2 and high glycemic load diets.2,4,5 The objective of this study was to support that there is a genetic, phenotypic link to acne and to identify environmental factors that may in uence acne severity.
METHODS
Study Design
The study was approved by the Institutional Review Board (IRB) at University Hospitals Cleveland Medical Center. The study was conducted at the Twins Day Festival in Twinsburg, Ohio on August 6-7, 2016. Data was analyzed from August 15, 2016 to February 2, 2017. The survey was administered through the REDCap (Research Electronic Data Capture) database. Informed consent was obtained from all study participants. Parental consent was obtained from participants under the age of 18.
Study Participants
A survey was administered to 139 identical and fraternal twin multiples (279 individuals). There was one set of triplets. The metrics surveyed included demographics, medical history, family history, social history, and physical activity. The twins were surveyed regarding acne incidence, age of onset, severity, and triggers. The majority of those surveyed were from the Midwest and Northeast regions of the United States. Height and weight were taken to determine body mass index (BMI).
Statistics
Data analysis was conducted using excel software (Microsoft Corporation; Redmond, WA). The proportion of concordant pairs, acne associations with other medical conditions, and acne triggers between groups were analyzed using the N-1 Chi-squared test. Comparison of BMI and physical activity