Open AccessFinger Length Ratio (2D:4D) and Aging
Author(s) -
Leonid Kalichman,
Valery Batsevich,
Eugene Kobyliansky
Publication year - 2020
Publication title -
collegium antropologicum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.138
H-Index - 42
eISSN - 1848-9486
pISSN - 0350-6134
DOI - 10.5671/ca.44.1.1
Subject(s) - digit ratio , menarche , medicine , anthropometry , ring finger , heritability , osteoarthritis , population , body mass index , demography , demographics , index finger , biology , anatomy , genetics , pathology , testosterone (patch) , alternative medicine , environmental health , sociology , gene
This study aimed to evaluate the association between the index to ring (2D:4D) finger length ratio and aging-related traits (hand osteoarthritis (OA), the osseographic score (OSS), and reproductive period), as well as to assess the heritability of finger length. A Chuvashian population-based sample included 802 males (mean age 46.98±17.10 years) and 738 females (mean age 48.65±16.62 years). Age, sex, basic demographics, anthropometric data, reproductive indices (age at menarche, menopausal age, and length of the reproductive period), and x-rays of both hands were collected. Finger length ratio was measured on x-ray and each hand was visually classified as either type 1 – 2D>4D; type 2 ― 2D=4D; or type 3 ― 2D<4D. Hand OA was defined by the number of affected joints (Kellgren-Lawrence score ≥2) and the total of Kellgren-Lawrence scores (total OA score). OSS is a skeletal biomarker that comprises osteoporotic and OA changes observable on a hands x-ray. We calculated the familial correlations and performed a heritability analysis of 2D:4D ratio traits in a studied sample. After comparing the OA variables of individuals with different finger length ratio types (after adjustment for age and BMI) significant differences were found only in females between finger ratio types of the right hand in a number of affected joints (F=3.153, p=0. 043) and finger ratio types of the left (F=3.330, p=0. 036) and right (F=2.397, p=0. 047) hands of the total OA score. Females with type 3 ratio had the highest adjusted values of hand OA parameters. Results of one-way ANCOVA for finger length ratio types of the right hand showed a significant difference in OSS (df =2, F=7.569, P=0.001), after adjustment for age, sex, and BMI. The posthoc comparison showed that individuals with type 3 (2D<4D) ratio showed significantly higher OSS scores than ones with type 1 (p=0.012) and type 2 (p=0.003). In an analysis of finger length ratio types of left hand also a significant difference in OSS was found (df=2, F=3.290, P=0.038). The posthoc comparison showed that individuals with type 3 ratio showed significantly higher OSS scores than ones with type 2 (p=0.33) ratio. We found that a low finger length ratio, a masculine visually evaluated finger length ratio type, was associated with later menarche and a shorter reproductive period. No association was found with menopausal age. Familial correlations of finger length ratio traits showed no significant correlation for spouses, however, parent-offspring (0.15―0.28, p<0.001) and sibling correlations (0.13―0.38, p<0.009) were found significant. Heritability (H2) of visual classification of finger length ratio was 0.36 for the left and 0.28 for the right hand; finger ratio was 0.55 and 0.66, respectively; the ray ratio was 0.49 and 0.59, respectively, thus indicating the existence of a clear familial aggregation of finger length ratio variation in the Chuvashian pedigrees, which cannot be explained by pure common environmental effects.