美国北卡罗来纳州高点大学James M Smoliga团队研究了食指与无名指的指长比率是否为好运的生物标志物。2021年12月15日出版的《英国医学杂志》发表了这项成果。

为了探讨随机、薄弱的研究方法或不适当的报告是否会导致声称具有统计意义（但在生物学上毫无意义）的生物标志物关联，研究组将产前睾酮暴露的常见替代物和食指与无名指的指长比率（2D:4D）与随机好运指标之间的相关性作为模型，进行了一项横断面研究。

2015年5月至2017年2月，研究组在美国大学体育表演实验室共招募了176名成年人（74名女性，102名男性），包括大学生、教员和工作人员，均没有可能影响手指长度的受伤、疾病或医疗状况史。主要观察指标为2D:4D，可能受雄激素（骨矿物质含量、骨矿物质密度、体脂百分比）和好运（使用随机选择的扑克牌作为替代品）影响的身体成分参数。

2D:4D与所选身体成分参数显著相关，但相关性因性别、参与者手工测量和2D:4D测量方法（通过影印或射线照相）而异。然而，通过X光片测量的男性右手2D:4D与扑克手等级之间的相关性最强。

根据较低的2D:4D估计，产前暴露于更多睾酮会显著增加成年期的好运，也会调节身体成分（尽管程度较低）。虽然这些发现与大量研究报告一致，即2D:4D与许多看似不同的结果相关，但它们并不意味着提供确凿的证据，证明2D:4D是几乎所有事物的通用生物标志物。

相反，2D:4D和好运之间的联系仅仅是偶然的，它为医学和科学研究中的可重复性危机提供了一个“方便”的例子。生物学上合理的假设、试验的预先登记、强有力的方法学和统计分析、阴性结果的透明报告以及数据的无偏倚解释都是生物标志物研究和其他临床研究领域所必需的。

附：英文原文

Title: Giving science the finger—is the second-to-fourth digit ratio (2D:4D) a biomarker of good luck A cross sectional study

Author: James M Smoliga, Lucas K Fogaca, Jessica S Siplon, Abigail A Goldburt, Franziska Jakobs

Issue&Volume: 2021/12/15

Abstract:

Objectives To explore whether random chance, weak research methodology, or inappropriate reporting can lead to claims of statistically significant (yet, biologically meaningless) biomarker associations, using as a model the relation between a common surrogate of prenatal testosterone exposure, second-to-fourth digit ratio (2D:4D), and a random indicator of good luck.

Design Cross sectional study.

Setting University sports performance laboratory in the United States. Data were collected from May 2015 to February 2017.

Participants 176 adults (74 women, 102 men), including university students, faculty, and staff with no history of injuries, disease, or medical conditions that would affect digit length.

Main outcome measures 2D:4D, body composition parameters potentially influenced by androgens (bone mineral content, bone mineral density, body fat percentage), and good luck (using poker hands from randomly selected playing cards as a surrogate).

Results 2D:4D significantly correlated with select body composition parameters (Spearman’s rs range 0.26 to 0.23; P<0.05), but the correlations varied by sex, participant hand measured, and the method of measuring 2D:4D (by photocopy or radiography). However, the strongest correlation observed was between right hand 2D:4D in men measured by radiograph and poker hand rank (rs=0.28, P=0.004).

Conclusions Greater prenatal exposure to testosterone, as estimated by a lower 2D:4D, significantly increases good luck in adulthood, and also modulates body composition (albeit to a lesser degree). While these findings are consistent with a wealth of research reporting that 2D:4D is related to many seemingly disparate outcomes, they are not meant to provide confirmatory evidence that 2D:4D is a universal biomarker of nearly everything. Instead, the associations between 2D:4D and good luck are simply due to chance, and provide a “handy” example of the reproducibility crisis within medical and scientific research. Biologically sound hypotheses, pre-registration of trials, strong methodological and statistical analyses, transparent reporting of negative results, and unbiased interpretation of data are all necessary for biomarker studies and other areas of clinical research.

DOI: 10.1136/bmj-2021-067849

Source: https://www.bmj.com/content/375/bmj-2021-067849