Age-related progression of androgenetic alopecia: Statistical analysis of 5372 Japanese men

To the Editor: Androgenetic alopecia (AGA) is widely observed in men worldwide. It can evoke feelings of inferiority by symbolizing premature aging, potentially impacting self-esteem and interpersonal relationships. The progression of AGA is globally assessed using the revised Norwood–Hamilton classification (NH classification).1,2 This scale quantifies the pattern of progression and extent of hair loss, which is crucial for clinical evaluation and treatment decisions. Although AGA is known to progress with age, further research is still needed to address the details of the relationship between the progression of AGA and age3 We hypothesized that there would be significant differences in median age across NH classifications.