Serum Vitamin D Levels and Life-Threatening Respiratory Syncytial Virus Infection in Previously Healthy Infants.

BACKGROUND: 25-hydroxyvitamin D (VD) effects on lung function and immune-modulation might affect respiratory syncytial virus (RSV) infection outcomes. We aimed to assess VD levels on admission and their association with life-threatening RSV disease (LTD). METHODS: A prospective cohort study was conducted during 2017-2019. Previously healthy infants aged <12 months, hospitalized with a first episode of RSV infection, were enrolled. LTD was defined by need for intensive care and ventilatory support. Serum VD levels <20 ng/mL were categorized as deficient, and 20-29.9 ng/mL as insufficient. RESULTS: Of 125 patients studied, 73 (58%) were male. Median age was 4 months. Twenty-two patients developed LTD. No differences in viral load were seen between cases with LTD and controls (P = .94). Patients who developed LTD had significantly lower VD levels: median 18.4 ng/mL (IQR, 15.1-26.9 ng/mL) versus 31.7 ng/mL (IQR, 23.6-42.0 ng/mL), P < .001; 59% of infants with LTD had VD deficiency compared with 12% in those with better outcome. Multivariable regression analysis confirmed VD deficiency as a risk factor (odds ratio, 11.83; 95% confidence interval, 3.89-35.9; P < .001). CONCLUSIONS: These findings provide additional evidence for the development of strategies to prevent severe RSV infections.

Time course of the serum gonadotropin surge, inhibins, and anti-Müllerian hormone in normal newborn males during the first month of life.

CONTEXT: Newborns with ambiguous genitalia or males with nonpalpable gonads usually require an early assessment of the presence and functional state of testicular tissue. OBJECTIVE: Our objective was to characterize the precise ontogeny of the serum patterns of gonadotropins, testosterone, anti-Müllerian hormone (AMH), and inhibins in normal newborn boys. DESIGN: We conducted a cross-sectional and longitudinal study. SUBJECTS: Serum samples were obtained in 57 boys and 13 girls on d 2 of life. A second sample was obtained on d 7, 10, 15, 20, and 30 (boys) and on d 30 (girls). MAIN OUTCOME MEASURES: Serum levels of gonadotropins, testosterone, AMH, and inhibins were measured. RESULTS: In males, LH and FSH were undetectable or very low on d 2. By d 7, LH increased to 3.94 +/- 3.19 IU/liter (mean +/- sd) and FSH to 2.04 +/- 1.67 IU/liter. LH/FSH ratios were 0.40 +/- 0.11 (d 2) and 2.02 +/- 0.20 (d 30). AMH rose from 371 +/- 168 pmol/liter (d 2) to 699 +/- 245 pmol/liter (d 30), and inhibin B rose from 214 +/- 86 ng/liter (d 2) to 361 +/- 93 ng/liter (d 30). The inhibin alpha-subunit precursor (pro-alphaC) remained stable during the first month of life. Testosterone levels were 66 +/- 42 ng/dl (d 2), 82 +/- 24 ng/dl (d 20), and 210 +/- 130 ng/dl (d 30). A sexual dimorphism was observed in AMH and inhibin B (lower in girls on d 2 and 30), in LH/FSH ratio (lower in girls on d 30) and in testosterone (lower in girls on d 30). CONCLUSIONS: Sertoli cell markers AMH and inhibin B are the earliest useful markers indicating the existence of normal testicular tissue.