The association between digit ratio (2D:4D) and blood pressure among children and adolescents

Digit ratio (2D:4D) is a biomarker of prenatal hormone exposure levels; this biomarker is negatively related to prenatal androgen exposure and positively related to prenatal estrogen exposure. We investigated the correlation between digit ratio (2D:4D) and blood pressure. A school-based survey of 687 adolescents aged 8-15 years was conducted. The ring finger (4D) and index finger (2D), systolic blood pressure (SBP), diastolic blood pressure (DBP), testosterone, and estradiol levels were measured. Their dietary behaviors and physical and sedentary activity time were surveyed. The results showed the 2D:4D ratio was not significantly related to SBP, DBP, or testosterone in boys and girls. However, it was significantly positively correlated with serum estradiol levels in boys. The 2D, 4D, multiplied index of digit ratio and length (MIDRL) and average of the index finger and ring finger (AIR) were directly related to SBP in both sexes (βs in boys were 4.16, 5.49, 2.95, and 5.25, respectively, P < 0.01; βs in girls were 3.43, 2.71, 3.02, and 3.36, respectively, P < 0.01) and were also indirectly associated with SBP through testosterone (P < 0.05). The 2D, 4D and AIR were indirectly related to DBP in girls through testosterone (P < 0.05). In conclusion, there were direct and indirect associations between finger-length indicators and blood pressure, which implies that prenatal hormone levels might be correlated with blood pressure in children and adolescents.