Acne incidence in preadolescents and association with increased body mass index: A population-based retrospective cohort study of 643 cases with age- and sex-matched community controls.

Background/objectives: Little is known about acne incidence in preadolescents and its potential association with body mass index (BMI). Our study aims to determine acne incidence in preadolescents and its association with BMI.

Methods: A population-based retrospective cohort study identified 7- to ≤12 year-olds with an initial acne diagnosis during 2010-2018, and incidence was calculated. Two age- and sex-matched controls without acne were randomly selected per case, and BMI was recorded.

Results: A total of 643 acne patients were identified. Annual age- and sex-adjusted incidence rate was 58.0 per 10,000 person-years, higher in females vs. males (89.2 vs. 28.2 per 10,000 person-years, p < .001), and increased with age (4.3, 24.4, and 144.3 per 10,000 person-years among 7-8, 9-10, and 11-12 year-olds, respectively, p < .001). Systemic medication use was associated with increasing BMI (odds ratio = 1.43 per 5 kg/m increase in BMI, 95% CI 1.07-1.92, p = .015). Median BMI percentile was higher among acne cases vs. controls (75.0 vs. 65.0, p < .001), as was the proportion with BMI ≥95th percentile (16.7% vs. 12.2%, p = .01).

Conclusion: Acne incidence is higher in preadolescent girls than boys and increases with age. Preadolescents with acne are more likely to be obese than those without acne. Those with higher BMIs are more likely to be given systemic treatment.