Objective: The etiology of bipolar disorder has yet to be fully elucidated, but differences in sex hormones have been suggested to play a role in its pathogenesis. An easily assessed marker of prenatal androgen exposure is the second-to-fourth-digit ratio (2D:4D) of the hand. In this study, we aimed to compare the 2D:4D ratio of patients with bipolar disorder to that of healthy controls. Methods: Seventy patients with bipolar disorder and 70 healthy controls, matched for age and sex, were included in the study. Finger lengths were measured from the palmar digital crease to the tip using a digital vernier caliper. Results: Patients with bipolar disorder had considerably higher right-hand 2D:4D ratios compared to controls. Both the right and left 2D:4D ratios of male patients were significantly greater than those of males in the control group. Female patients showed no differences in right or left 2D:4D ratio compared to healthy controls. Conclusion: These findings suggest that a high 2D:4D digit ratio of right hand is associated with the presence of bipolar disorder in males. Further large-scale, prospective studies are needed to explain the validity of this marker and its relationship with bipolar disorder.

中文翻译：

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双相障碍患者中指与第四指长度比（2D:4D）的调查

目的：双相情感障碍的病因尚未完全阐明，但已表明性激素的差异在其发病机制中起作用。一个容易评估的产前雄激素暴露标志物是手的第二至第四位数字比例 (2D:4D)。在这项研究中，我们旨在比较双相情感障碍患者与健康对照组的 2D:4D 比例。方法：本研究包括 70 名双相情感障碍患者和 70 名年龄和性别匹配的健康对照。使用数字游标卡尺测量从手掌数字折痕到尖端的手指长度。结果：与对照组相比，双相障碍患者的右手 2D:4D 比率要高得多。男性患者的左右 2D:4D 比率均显着大于对照组中的男性。与健康对照相比，女性患者的右侧或左侧 2D:4D 比率没有差异。结论：这些发现表明，右手的高 2D:4D 手指比例与男性双相情感障碍的存在有关。需要进一步的大规模前瞻性研究来解释该标志物的有效性及其与双相情感障碍的关系。