Association between the digit ratio (2D:4D), handgrip strength, wrist ratio, and body fat distribution in women with different carpal tunnel syndrome severity

Abstract

Background: To evaluate the relationship of the second to fourth digit ratio (2D:4D), a biomarker of prenatal sex hormone exposure, with wrist ratio (WR), wrist-palm ratio (WPR), body mass index (BMI), waist-hip ratio (WHR), and handgrip strength (HGS) in different carpal tunnel syndrome (CTS) severity.

Method: This study involved 90 female participants (aged 18 to 83) with CTS. According to CTS severity, the participants were divided into four groups: normal, mild, moderate, and severe. All parameters of hand anthropometry and body fat distribution were measured, and the mean 2D:4D, WR, WPR, HGS, BMI, and WHR values were compared based on CTS severity. Data were collected with a visual analog scale (VAS) for pain and a Likert (LS) scale for numbness severity.

Results: The mean age, 2D:4D, WD, WW, WR, WPR, BMI, and HGS values showed a significant differences between CTS severity groups. We found that lower 2D:4D and higher WPR and BMI were associated with increased risk of CTS (AUC = 0.728) after removing the effect of age. Bilateral hands were affected in 38.9 % (70/180) of participants. Regression analysis showed that lower HGS can be used as independent variable for predicting the females having bilateral affected hands. The LS score was considerably higher in the severe and moderate groups. Also, the VAS score was significantly higher in the severe group.

Conclusion: The findings of the study demonstrated an association between 2D:4D, WPR, and BMI among women, emphasizing the effect of intrauterine sex hormone exposure on late life CTS severity.

Keywords: 2D:4D; Body mass index; Carpal tunnel syndrome severity; Handgrip strength; Wrist ratio.