Visfatin levels in prepubertal children born small or large for gestational age.

Children born small (SGA) or large (LGA) for gestational age are prone to develop insulin resistance (IR) during childhood. Visfatin, a hormone with insulin-mimetic actions, has been associated with IR. This study was designed to examine whether serum level of visfatin is correlated with metabolic indices of IR, in prepuberty in association with the intrauterine growth pattern. The following parameters were evaluated at a mean age of 6.5±1.2 years in 155 prepubertal children born appropriate for the gestational age (AGA) (n=63), or SGA (n=42), or LGA (n=50): serum levels of visfatin, adiponectin, leptin, fasting glucose (G(F)) and insulin (I(F)), the homeostasis model assessment IR index (HOMA-IR), plasma lipids, anthropometric indices at birth and the time of evaluation, and obesity indices [waist circumference (WC), body mass index (BMI) and skinfold thickness]. The mean serum level of visfatin was lower in the SGA than in the AGA and the LGA children (9±5.2 vs. 11.8±5.1 and 12.7±5.6 ng/ml, respectively, p<0.01). Girls had lower visfatin levels than boys (10.4±4.3 ng/ml vs. 12.5±6.7 ng/ml, p<0.05). Visfatin was not correlated with IR indices. In multiple regression analysis visfatin level was positively correlated with birth weight z-score (t=2.56, beta=0.24, p<0.01) and crown to heel z-score (t=2.46, beta=0.22, p=0.014), independent of age, gender, maternal weight before pregnancy, maternal weight gain during pregnancy, BMI z-score, WC z-score, serum leptin and adiponectin, and HOMA-IR. In conclusion serum visfatin level was lower in prepubertal SGA children but not correlated with IR indices. Low birth weight was an independent predictor of visfatin level.

Vitamin D and parathormone levels of late-preterm formula fed infants during the first year of life.

BACKGROUND/OBJECTIVES: Preterm infants are at risk for low vitamin D but documentation on late-preterm infants is sparse. This prospective study monitored longitudinally vitamin D and parathormone (PTH) levels in late-preterm formula fed infants during the first year of life, taking into consideration in utero and postnatal growth, and season and diet. SUBJECTS/METHODS: The study population comprised 128 infants of gestational age (GA) 32-36 weeks, of which 102 were appropriate (AGA) and the remaining 26 were small for GA (SGA). Serum levels of vitamin D (25(OH)D), PTH calcium, phosphate (P) and alkaline phosphate were estimated at 2 and 6 weeks, and at 3, 6, 9 and 12 months of age. RESULTS: The 25(OH)D levels were relatively low at 2 and 6 weeks in both AGA and SGA infants (21±11, 20±7 ng/ml and 25±16, 23±8 ng/ml, respectively), but increased at 6 months (45±14, 47±10 ng/ml) and remained stable thereafter. SGA infants had lower 25(OH)D levels at 9 and 12 months (AGA 45±14, 47±18 ng/ml vs SGA 38±13, 37±13 ng/ml, P<0.05). Deficiency of 25(OH)D (<20 ng/ml) was found in 18.5% of measurements in 92 (72%) infants, and its insufficiency (20-32 ng/ml) was found in 29.2% of measurements in 99 (77.3%) infants. Most measurements with vitamin D <32 ng/ml were observed at the first three study points, where PTH showed an inverse association with 25(OH)D, reaching a plateau thereafter. CONCLUSIONS: Late-preterm, formula fed infants may have suboptimal vitamin D levels and elevated PTH, especially, during the first 3 months. Those born SGA may have lower vitamin D levels up to the end of the first year of life.