RESUMEN

BACKGROUND: The second-to-fourth digit ratio (2D:4D) is a marker of prenatal hormone exposure, which is negatively correlated with prenatal androgen and positively correlated with prenatal estrogen. The study was to analyze the association between 2D:4D and the first spermatorrhea to indirectly show the possible role of prenatal hormone during puberty development among boys. METHOD: The total of 367 boys aged 8-15 years were enrolled by using the stratified cluster sampling method. The variables of index finger (2D), ring finger (4D), height, weight, waist circumference (WC), skinfold thickness, testosterone and estradiol were measured, and the age at the first spermatorrhea was surveyed. RESULTS: The average age at the first spermatorrhea was 12.15 years. The 2D:4D was not related to first spermatorrhea, circulating testosterone in boys (P > 0.05), however, was positively correlated with circulating estradiol (P < 0.05). The direct association (OR value) between 4D, average of index finger and ring finger (AIR) and first spermatorrhea were 2.79 and 2.29, and the mediating effect (OR value) of which were 1.95 and 2.01 by testosterone, accounting for 41.18% and 46.73% of the total effect, respectively. The 2D, MIDRL, lean body mass (LBM) were indirectly related to first spermatorrhea by testosterone, the mediating effects (OR value) were 2.11, 1.71 and 2.41, respectively. CONCLUSION: The prenatal androgen exposure may be directly and indirectly related to first spermatorrhea. In addition, the high prenatal estrogen exposure may be indirectly associated with first spermatorrhea by testosterone.

Asunto(s)

Eyaculación , Dedos/anatomía & histología , Desarrollo Sexual , Adolescente , Niño , China , Estradiol/sangre , Humanos , Masculino , Testosterona/sangre

RESUMEN

Objective · To understand boys' pubertal timing in school in two urban districts of Chongqing and explore the relationship between pubertal timing and physical activity or sleeping time. Methods · Using a stratified random cluster sampling, 3403 boy students (10-18 year-old) were selected and completed the physical examination and questionnaire survey. 1282 participants experiencing first spermatorrhea were chosen as research objects. According to age of first spermatorrhea, the objects were divided into on-time group (964 cases) and later group (318 cases). Results · The composition of weekly high (χ2=11.488, P=0.009), medium (χ2=7.829, P=0.050) physical activity and daily sleeping time (χ2=17.803, P=0.000) in two groups were significantly different. Controlling covariates (age, height and weight), compared with boys in on-time group, later group boys were less likely to engage in 5-7 days (OR=0.596, 95% CI: 0.367-0.967) and 3-4 days (OR=0.590, 95% CI: 0.370-0.941) high physical activity every week, and 9-11 h (OR=0.207, 95% CI: 0.088-0.489) sleep every day. Conclusion · The age of first spermatorrhea in boys might be associated with the intensity of weekly physical activity and daily sleeping time.