The association between digit ratio (2D:4D) and overweight or obesity among Chinese children and adolescents: A cross-sectional study.

BACKGROUND: The aim of this study was to analyze the relationship between 2D:4D and childhood overweight or obesity, which might indirectly show the role of prenatal hormone in childhood overweight or obesity.

METHODS: Using stratified cluster sampling approach, a school-based cross-sectional investigation was undertaken among 687 children and adolescents aged 8-15 years. Each participant's index finger (2D) and ring finger (4D) length, height, weight, testosterone, and estradiol levels were measured, and their dietary behaviors, physical and sedentary activities were also surveyed.

RESULTS: The prevalence of overweight or obesity among children and adolescents aged 8- and 12-15 years was 36.0% and 25.9%, respectively (P < 0.05). There were no associations between 2D:4D and overweight or obesity in both boys and girls (P > 0.05). However, 2D and multiplying index of digit ratio and length (MIDRL) associated directly with overweight or obesity among boys (OR (95%CI) were 1.45 (1.00, 2.14), 1.46 (1.01, 2.11), respectively), and was indirectly related to overweight or obesity by testosterone (OR were 1.30, 1.26, respectively).

CONCLUSIONS: In boys, 2D and MIDRL were directly related to overweight or obesity, and indirectly associated with overweight or obesity by testosterone, which suggested that prenatal hormone exposure might associate with overweight or obesity among boys.