Evaluation of vitamin D status and its correlation with gonadal function in children at mini-puberty.

CONTEXT: The effects of Vitamin D on reproductive function in adults have gained interest. Studies have demonstrated some associations. Hypothalamic-pituitary-gonadal axis is activated during the first 6 months of life, called as mini-puberty. This HPG activation is important for future gonadal function. There are no data regarding the association of gonadal hormones and 25(OH)D levels at mini-puberty. Demonstration of any association would form the basis for studies that will search for the effects of 25(OH)D on gonadal hormones at mini-puberty.

OBJECTIVE: To characterize the associations between 25(OH)D levels and gonadal hormones at mini-puberty.

DESIGN: Cross-sectional cohort analysis.

PATIENT(S) OR OTHER PARTICIPANT(S): A total of 180 (94 boys and 86 girls) healthy appropriate-for-gestational-age neonates were included.

MAIN OUTCOME MEASURE(S): 25(OH)D, LH, FSH, total testosterone, oestradiol, AMH and inhibin B levels were measured at postnatal 30-45 days. All infants were divided into three groups including vitamin D deficiency (<10 ng/mL), vitamin D insufficiency (10-20 ng/mL) and vitamin D sufficiency (>20 ng/mL). Correlations between vitamin D status and reproductive hormones were analysed.

RESULT(S): Total testosterone level was higher (mean: 0.52 ± 0.32 vs 0.26 ± 0.2 ng/mL; P: 0.008) and inhibin B was lower in 25(OH)D deficient than sufficient girls (mean: 21.2 ± 15.71 vs 53.25 ± 47.25 pg/mL; P: 0.021).

CONCLUSION(S): A modest effect of 25(OH)D was identified on total testosterone and inhibin B in girls at mini-puberty. The 25(OH)D may have an effect on gonadal function during early life. Randomized controlled trials could clarify the importance of vitamin D on gonadal hormones at mini-puberty.