Yousaf Ahmed, Lee Justin, Fang Wei, Kolodney Michael S
Department of Dermatology, West Virginia University, Morgantown.
West Virginia Clinical and Translational Science Institute, Morgantown.
JAMA Dermatol. 2021 Mar 10. doi: 10.1001/jamadermatol.2021.0144.
Alopecia areata (AA) is a complex immune-mediated disorder that causes nonscarring hair loss. Previous reports have documented preferential targeting of pigmented hair follicles with sparing of gray, nonpigmented hair follicles in alopecia lesions. Thus, immune targeting of melanogenesis-associated proteins in melanocytes and keratinocytes represents a potential mechanism for the inflammation that targets anagen hairs in alopecia areata.
To investigate the association of alopecia areata with hair color among White residents of the UK.
DESIGN, SETTING, AND PARTICIPANTS: This matched, case-control study conducted in October 2020 used a large prospectively acquired cohort and included data that were collected from the UK Biobank, a large-scale prospective resource designed to study phenotypic and genotypic determinants in adults. A total of 502 510 UK Biobank participants were reviewed for inclusion. Among these individuals, 1673 cases of alopecia areata with reported hair color were captured and matched by age and sex to 6692 controls without alopecia areata using 1:4 matching.
Conditional logistic regression analysis was performed, in which the outcome variable was alopecia areata and the main predictor was natural hair color before graying. The variables considered included diabetes, hypothyroidism, hyperthyroidism, and vitiligo.
Of 464 353 participants, 254 505 (54.8%) were women, and the mean (SD) age for those with alopecia areata was 46.9 (16.5) years. Alopecia areata was significantly more common in individuals with black (adjusted odds ratio [aOR], 2.97; 95% CI, 2.38-3.71) and dark brown hair (aOR, 1.26; 95% CI, 1.11-1.42) compared with light brown hair. In contrast, blond individuals exhibited significantly decreased alopecia areata compared with those with light brown hair (aOR, 0.69; 95% CI, 0.56-0.85). Red hair color was not significantly different from light brown hair.
The findings of this matched case-control study seem to indicate that alopecia areata is modulated by natural hair color, preferentially targeting darker hair. Our results support a previously proposed model of alopecia areata in which immunity is directed against melanogenesis-associated proteins in the anagen hair follicles. However, further study is needed to more precisely understand the immunopathogenic association between alopecia areata and hair color.
斑秃（AA）是一种复杂的免疫介导性疾病，可导致非瘢痕性脱发。既往报道记录了斑秃皮损中色素性毛囊被优先累及，而灰色、无色素毛囊则未受累。因此，黑素细胞和角质形成细胞中与黑素生成相关蛋白的免疫靶向作用可能是斑秃中生长期毛发炎症反应的潜在机制。
调查英国白人居民中斑秃与头发颜色的关联。
设计、地点和参与者：这项配对病例对照研究于2020年10月进行，使用了一个大规模前瞻性队列，纳入了从英国生物银行收集的数据，该生物银行是一个旨在研究成年人表型和基因型决定因素的大规模前瞻性资源。对总共502510名英国生物银行参与者进行了纳入审查。在这些个体中，共记录了1673例有报告头发颜色的斑秃病例，并按年龄和性别以1:4的比例与6692名无斑秃的对照进行匹配。
进行条件逻辑回归分析，其中结局变量为斑秃，主要预测因素为白发前的自然头发颜色。纳入考虑的变量包括糖尿病、甲状腺功能减退、甲状腺功能亢进和白癜风。
在464353名参与者中，254505名（54.8%）为女性，斑秃患者的平均（标准差）年龄为46.9（16.5）岁。与浅棕色头发的个体相比，黑色头发（校正比值比[aOR]，2.97；95%置信区间[CI]，2.38 - 3.71）和深棕色头发（aOR，1.26；95% CI，1.11 - 1.42）的个体患斑秃的情况明显更常见。相比之下，金发个体患斑秃的情况与浅棕色头发个体相比显著降低（aOR，0.69；95% CI，0.56 - 0.85）。红色头发与浅棕色头发无显著差异。
这项配对病例对照研究的结果似乎表明斑秃受自然头发颜色的调节，更倾向于累及深色头发。我们的结果支持了先前提出的斑秃模型，即免疫反应针对生长期毛囊中与黑素生成相关的蛋白。然而，需要进一步研究以更精确地了解斑秃与头发颜色之间的免疫发病机制关联。
