Salivary Sex Steroid Levels in Infants and Their Relation with Infantile Colic

INTRODUCTION: Hypothalamic-pituitary-gonadal axis is active during minipuberty, timing of which coincides with infantile colic. To the best of our knowledge, the relationship between these entities has not been investigated yet.
METHODS: Saliva samples were collected from 15- to 60-day-old term infants (n=139) between 9 am and 5 pm. Group 1 included infants with infantile colic (n=68, 54.4% female). Remaining healthy infants constituted Group 2 (n=71, 47.9% female). The salivary levels of estradiol (Esal) in females and testosterone (Tsal) in males were studied in duplicate by using the ELISA method.
RESULTS: The median (25th-75th centile) age and birth week for all infants were 33 (29-43) days and 39 (38.1-40) weeks, respectively. Levels of Tsal in males [Group 1, 73.35 (59.94-117.82) pg/mL vs Group 2, 77.66 (56.49-110.08) pg/mL, p=0.956] and Esal in females [Group 1, 3.91 (2.76-5.31) pg/mL vs Group 2, 4.03 (1.63-12.1) pg/mL, p=0.683] were similar among the groups. However, only in subjects with infantile colic (Group 1), Esal and body mass index (BMI) standard deviation scores of females were slightly correlated (Group 1, rs= 0.393, p=0.016 vs. Group 2, rs= 0.308, p=0.076) and there was a significant correlation between the sampling time and Tsal in males (Group 1, rs= 0.469, p=0.009 vs. Group 2, rs= -0.005, p=0.976).
DISCUSSION AND CONCLUSION: Random salivary sex steroid levels were similar among groups. However, only in subjects with infantile colic, salivary estradiol levels in females were positively correlated with BMI and salivary testosterone levels were higher later in the day among males. Thus, sex steroid production might be altered during minipuberty in subjects with infantile colic.