Twin study highlights environmental factors that may aggravate acne.
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.
The study, led by Amanda Suggs, MD, of University Hospitals Cleveland Medical Center, appears in the April issue of the Journal of Drugs in Dermatology.
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; 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 coursel to acne development. Thus, regular exercise and lower BMI may keep acne at bay," they noted.
They also analyzed 56 pairs of identical twins with acne, who reported different severities, and found that the twin with more severe acne was more likely to report that sun exposure (P = .048), cosmetic product use (P = .002), and sugar intake (P = .048) aggravated their acne. Refined carbohydrates, as an aggravating factor, approached statistical significance, they said.
A separate analysis of 45 pairs of female identical twins with different degrees of acne severity produced similar findings. There were no significant differences between acne severity groups in terms of menstruation flare frequency or with oral contraceptive use. The twin with more severe acne, however, "was more likely to report aggravation of acne with sun exposure," cosmetic use, and sugar intake, all associations which reached statistical significance. They were also more likely to report that refined carbohydrates and intake of fried foods aggravated their acne, associations that approached statistical significance.
"This twin study provides further support for reducing intake of sugar and refined carbohydrates to decrease acne severity in susceptible individuals," the authors wrote. "For females, reducing intake of fried foods may also help."
There's a twist to their results: The finding that those with more severe acne reported worsening symptoms with sun exposure "conflicts with prior research, which has found that acne improves with sun," the authors wrote, adding that "perhaps the data was confounded by comedogenic sunscreen use."
The study authors reported no disclosures or external funding.
SOURCE: Suggs A et al. J Drugs Dermatol. 2018 Apr;l 7(4):380-2.
COMMENTARY BY DR. SIDBURY
The pathogenesis of acne is multifactorial. Investigators (and parents) have long parsed the relative contribution of genetic and environmental factors.
Suggs et al. surveyed 101 pairs of identical twins and 53 sets of fraternal twins or triplets attending the 2016 Twins Day Festival to learn more. Identical twins were more likely to both have acne than fraternal twins (64% vs. 49%), supporting a genetic role. Investigators likewise noted worse acne with higher BMI, greater refined carbohydrate intake, and less exercise.
Contrary to many prior studies, and my own anecdotal experience, acne seemed to be worse with sun exposure. Though hardly settled science, this study will offer ammunition for parents who want to leverage their child's acne toward better health behaviors: Eat less sugar; exercise more; and moderate sun exposure. If only the investigators had found that texting worsened acne; parents might have nominated them for the Nobel Prize by acclimation!
BY RANDY DOTINGA
FROM THE JOURNAL OF DRUGS IN DERMATOLOGY
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|Date:||Jun 1, 2019|
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