Second to fourth digit ratio, sex differences and antropometric measuments: their relationship in children

BACKGROUND: The aim of this study was to determine the effect of socio-demographic factors and anthropometric measurements on 2/4 digit ratio in the school aged children. METHODS: This cross-sectional study was completed in primary and secondary schools in the city center of Canakkale, Turkey. The students were seated at a table by the responsible doctor, and were asked to extend the palm of the right and left hand in the schools. Using a Vernier Caliper the 2/4 fingers were measured from the palm twice, and the results were noted together with socio-demographic information. Weight, length, waist and hip measurements were taken while students were behind a folding screen. RESULTS: A total of 1860 students from 5-14 years were included in the study. The right hand 2/4 digit ratio was 0.9765 +/- 0.035 and the left hand ratio was 0.9716 +/- 0.036 for girls. For the boys the ratios were 0.9688 +/- 0.035 for right hand and 0.9653 +/- 0.033 for left hand. The digit ratios of girls were significantly higher than boys and the right hand ratio was even greater. The 2/4 digit measurements of both hands of students were positively correlated with each other. In regression model left hand 2/4 ratio is dependent hip circumference, monthly income and gender as adjusted r(2) 0.051. The right hand 2/4 ratio was dependent gender, monthly income, hip circumference and birthweight as adjusted r(2) 0.041. CONCLUSIONS: The 2/4 digit ratio of school-aged in Turkish children differed based on gender. Digit ratios depend on the hip circumference, gender (girls have higher ratio), birthweight, gestation week and monthly income. Further research, especially the effect of monthly income, is needed.