Isotretinoin Treatment in Adolescence and Adult Height

Importance: Isotretinoin is an effective treatment for moderate to severe acne, but concerns exist that exposure during adolescence could impair linear growth. Objective: To examine whether isotretinoin use in adolescence is associated with reduced adult height. Design, Setting, and Participants: This nationwide population-based cross-sectional study analyzed individuals eligible for military conscription in Denmark between January 1, 2001, and December 31, 2015, including all men and women volunteers. Conscription records were linked via unique personal identifiers to prospectively collected data from nationwide Danish registries. Individuals without a recorded height or with implausible height values were excluded. Data were analyzed from April 2025 to January 2026. Exposures: Prior use of isotretinoin, oral tetracycline-class antibiotics, or topical acne therapies, ascertained from linked prescription records before outcome assessment. Individuals without prescribed acne treatment or hospital-diagnosed acne served as the reference group. Main Outcomes and Measures: Adult height measured at conscription. Linear regression models adjusted for birth cohort and educational level were used to estimate mean differences in height. The predefined minimal clinically important difference was 5 cm or greater. Analyses were stratified by age at isotretinoin initiation and cumulative dose before conscription. Stunting was examined as a secondary outcome. Results: The study included 379 196 individuals, of whom 368 338 were men (16 739 [4.5%] isotretinoin users) and 10 858 were women (278 [2.6%] isotretinoin users). Median age at conscription was 19.0 years (IQR, 18.7-20.0 years) among men and 19.2 years (IQR, 18.7-20.5 years) among women. The mean (SD) height at age 19 years was 180.4 (6.7) cm in men and 168.3 cm (5.9) in women. There was little variation in adult height across exposures. Compared with the reference group, in the isotretinoin group, the adjusted mean difference in height was 0.31 cm (95% CI, 0.20-0.41 cm) among men and 0.25 cm (95% CI, -0.47 to 0.96 cm) among women; both estimates were below the predefined minimal clinically important difference. Findings were consistent across analyses stratified by age at initiation, cumulative dose, and when using stunting as the outcome. Conclusions and Relevance: In this nationwide cross-sectional study, isotretinoin for acne was not associated with reduced adult height. These findings may inform evidence-based decision-making when considering isotretinoin treatment during adolescence.