Twin study highlights environmental factors that may aggravate acne

A survey conducted at the world’s largest twin celebration provides more evidence that twins share a genetic propensity toward acne, and provides information about several aggravating factors.

The study “further supports that there may be a genetic phenotypic link, though social and environmental factors may also have an influence in the disease process,” the authors wrote.

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Previous twin research has linked genetic factors to 80% of acne variance, with environmental factors, such as stress and low intake of produce, believed to account for the rest of the risk (J Invest Dermat. 2002;119[6]:1317-22). For the new study, researchers surveyed twins at the 2016 Twins Day Festival in Twinsburg, Ohio. Thousand of twins – and triplets and quadruplets – from around the world attend the annual event.

After incomplete surveys were discarded, the survey population included 202 identical twins (101 pairs) and 53 fraternal twins or triplets. (A set of triplets was included in addition to 25 pairs of twins.) The majority of participants were female: 23% of identical twins and 17% of the fraternal twins and triplets were male. The mean age was 29 years among the identical twins and 21 years among fraternal twins.

Identical twins were more likely to both have acne (64%) than fraternal twins (49%), which supports the results of previous studies that suggest “acne is largely attributable to genetics,” the authors observed. Among identical twins, those with acne were more likely to have polycystic ovarian syndrome (P = .045), anxiety (P = .014), and asthma (P = .026).

“Identical twin pairs with acne had a higher BMI [body mass index] and exercised less than those without,” the researchers added. These two associations were statistically significant, both for higher BMI (P = .020) and for less exercise (P = .001). “This suggests that a higher BMI and lack of exercise may contribute [along with genetics of course] to acne development. Thus, regular exercise and lower BMI may keep acne at bay,” they noted.