Park Hee Ung, Chung Kyung Bae, Kim Do-Young
Department of Dermatology, Hanyang University Medical Center, Myongji Hospital, Goyang, Republic of Korea.
Department of Dermatology, Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
JAAD Int. 2024 Feb 15;15:121-126. doi: 10.1016/j.jdin.2024.02.005. eCollection 2024 Jun.
The conventional 20% threshold for hair diameter diversity (HDD), widely accepted for diagnosing androgenetic alopecia (AGA) in the vertex area, has not quantitatively analyzed.
To validate the HDD 20% threshold for AGA and develop a refined, Korean-specific criterion.
This study involved 240 male patients with AGA, categorized by the V stages of the basic and specific classification. Phototrichogram images of the vertex region were analyzed using Image J software for hair thickness measurement.
Receiver operating characteristic curve analysis determined the 45 μm hair diameter threshold as the most diagnostic for AGA, with an area under the curve value of 0.884 and a Youden index of 0.659. Optimal AGA diagnosis was achieved when over 21% of hair had a diameter of ≤45 μm.
Restriction to Korean male limits its applicability to a broader population, and using a specific hair diameter threshold does not account for individual variations in hair characteristics.
The study validates the conventional HDD 20% threshold and proposes a more appropriate 45 μm threshold for Korean males, beyond the 40 μm. It concludes that while the HDD 20% remains a key method for early detection of vertex AGA, the definition of thin hair should be ethnicity-specific.
用于诊断头顶区域雄激素性脱发（AGA）的传统20%毛发直径差异（HDD）阈值尚未进行定量分析。
验证用于AGA诊断的HDD 20%阈值，并制定一个更精确的、针对韩国人的标准。
本研究纳入了240例男性AGA患者，根据基本和特定分类的V期进行分类。使用Image J软件分析头顶区域的毛发照片，以测量毛发厚度。
受试者工作特征曲线分析确定45μm的毛发直径阈值对AGA诊断最具诊断价值，曲线下面积值为0.884，约登指数为0.659。当超过21%的毛发直径≤45μm时，可实现最佳的AGA诊断。
研究对象仅限于韩国男性，限制了其在更广泛人群中的适用性，且使用特定的毛发直径阈值未考虑毛发特征的个体差异。
该研究验证了传统的HDD 20%阈值，并为韩国男性提出了一个更合适的45μm阈值，而非40μm。研究得出结论，虽然HDD 20%仍然是早期检测头顶AGA的关键方法，但细发的定义应因种族而异。
