Pre- and peripubertal sex steroids are inversely associated with birth weight in preterm boys

Objective The relationship between sex hormone concentrations during childhood and birth weight (BW) is poorly understood. We aimed to investigate this relationship and the associations with anthropometric data at 5, 6, 7, 8, and 10 years of age in preterm boys. Design A prospective longitudinal single-centre study, including 58 boys with a BW of 1325-3320 g and gestational age (GA) of 32 + 2 to 36 + 6 weeks. Patients and Measurements Data on GA, BW and anthropometric data between 5 and 10 years of age were recorded. Testicular development was assessed at 8 and 10 years of age. Serum concentrations of sex steroids were analysed with gas chromatography-tandem mass spectrometry at 5-10 years and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) with immunoassays at 10 years of age. Results At 8 years of age, testosterone and estrone correlated negatively with BW, (rho = -0.35, p = .021) and (rho = -0.34, p = .024), respectively. At 10 years of age, testosterone, dihydrotestosterone, estrone and estradiol correlated negatively with BW (rho = -0.39, p = .010), (rho = -0.38, p = .013), (rho = -0.44, p = .003) and (rho = -0.36, p = .019), respectively. Weight gain from birth correlated with testosterone at 5 years (rho = 0.40, p = .002), 7 years (rho = 0.30, p = .040), 8 years (rho = 0.44, p = .003) and 10 years (rho = 0.40, p = .008) of age. At 10 years of age, testosterone correlated with LH (rho = 0.42, p = .006) and FSH (rho = 0.33, p = .033) but not with testicular volume. Conclusions Lower BW was associated with increased sex steroid concentrations from 8 years of age, independently of clinical signs of puberty.

Automated summary

This study found that lower birth weight was associated with increased sex hormone concentrations during childhood. Weight gain after birth was positively correlated with sex hormone concentrations.