The Second Hospital of Hunan University of Chinese Medicine, Changsha, Hunan, China.
The First Hospital of Hunan University of Chinese Medicine, Changsha, Hunan, China.
Medicine (Baltimore). 2024 Jun 14;103(24):e38426. doi: 10.1097/MD.0000000000038426.
Previous observational studies revealed controversy about the effect of circulating antioxidants on risk of alopecia. In the present study, we investigated the causal relationships between diet-derived circulating antioxidants and 2 non-scarring alopecia using Mendelian randomization (MR). Instrumental variables for antioxidants (lycopene, retinol, ascorbate, β-carotene, α-tocopherol, and γ-tocopherol) were selected from published studies. Data for alopecia areata (AA) and androgenetic alopecia (AGA) was obtained from the FinnGen study project (R9 released in 2023), including 195 cases and 201,019 controls for AGA and 682 cases and 361,140 controls for AA. We used the inverse variance weighted method as the primary MR method. Three additional methods were used as sensitivity analysis to validate the robustness of the results. We found a causal relationship between absolute β-carotene levels and AGA risk (P = .039), but not with AA (P = .283). The results of Wald ratio showed a protective effect of absolute β-carotene levels against AGA, with per 0.1 ln-transformed β-carotene being associated with a 76% lower risk of AGA (OR: 0.24, 95% CI: 0.06-0.93). Based on the fixed effects inverse variance weighting results, we found that α-tocopherol was protective against both AGA (P = .026) and AA (P = .018). For each unit increase in α-tocopherol, the effects of change in AGA and AA were 0.02 (95% CI: 0.00-0.61) and 0.10 (95% CI: 0.01-0.67), respectively. The results did not reveal any other causal relationships. Our study identified 3 causal associations of antioxidants with the risk of non-scarring alopecia. These results provide new insights into the prevention of non-scarring alopecia through diet.
先前的观察性研究表明，循环抗氧化剂对脱发风险的影响存在争议。在本研究中，我们使用孟德尔随机化（MR）方法研究了饮食来源的循环抗氧化剂与 2 种非瘢痕性脱发之间的因果关系。抗氧化剂（番茄红素、视黄醇、抗坏血酸、β-胡萝卜素、α-生育酚和γ-生育酚）的工具变量选自已发表的研究。脱发症（AA）和雄激素性脱发（AGA）的数据来自 FinnGen 研究项目（2023 年发布的 R9 版本），包括 195 例 AGA 病例和 201019 例对照、682 例 AA 病例和 361140 例对照。我们使用逆方差加权法作为主要的 MR 方法。还使用了另外 3 种方法作为敏感性分析，以验证结果的稳健性。我们发现绝对β-胡萝卜素水平与 AGA 风险之间存在因果关系（P=0.039），但与 AA 无关（P=0.283）。Wald 比值的结果表明，绝对β-胡萝卜素水平对 AGA 有保护作用，β-胡萝卜素每增加 0.1ln 转换单位，AGA 的风险降低 76%（OR：0.24，95%CI：0.06-0.93）。基于固定效应逆方差加权结果，我们发现α-生育酚对 AGA（P=0.026）和 AA（P=0.018）均有保护作用。每增加一个单位的α-生育酚，AGA 和 AA 的变化效应分别为 0.02（95%CI：0.00-0.61）和 0.10（95%CI：0.01-0.67）。结果没有显示出其他任何因果关系。本研究确定了 3 种抗氧化剂与非瘢痕性脱发风险之间的因果关系。这些结果为通过饮食预防非瘢痕性脱发提供了新的见解。
