[Relationship between serum 25-hydroxyvitamin D and bone mineral density in children under 7 years old].

OBJECTIVE: To evaluate the endogenous vitamin D level and its correlation with bone mineral density (BMD) in children under 7 years old. METHODS: Totally 6 838 children who visited the Growth and Development Clinic due to "growth retardation, night terrors, hyperhidrosis, and dysphoria" were enrolled in the study. Serum 25-hydroxyvitamin D [25(OH)D] level was measured by chemiluminescence, whereas individual BMD was measured by quantitative ultrasound. RESULTS: Among all subjects, serum 25(OH)D level was 34 ± 14 ng/mL, and the Z value of BMD was -0.49 ± 0.54. With increasing age, serum 25(OH)D level and BMD decreased gradually (P<0.01), and the detection rates for vitamin D deficiency and low BMD increased gradually (P<0.01). Compared with those with sufficient vitamin D, children with vitamin D deficiency had a significantly lower BMD (P<0.01) and a significantly higher detection rate for low BMD (P<0.01). 25-(OH)D level showed a positive linear correlation with BMD in children with vitamin D deficiency (P<0.01). CONCLUSIONS: Preschool and school-age children have severer vitamin D deficiency than infants. Vitamin D level may be correlated with BMD within a certain range.

High prevalence of vitamin D and calcium deficiency among pregnant women and their newborns in Chengdu, China.

BACKGROUND: Vitamin D and calcium deficiency is common in pregnant women and newborn infants. There are few data about the prevalence of hypovitaminosis D during pregnancy and infancy in China. We assessed vitamin D status of pregnant women and their neonates in Chengdu, Sichuan province, China. METHODS: Maternal serum and cord blood levels of calcium, 25-hydroxyvitamin D [25(OH)D], alkaline phosphatase, and parathyroid hormone (PTH) were studied in 77 urban and rural mother-neonate pairs at term. RESULTS: The mean level of maternal serum 25(OH)D was 35.95+/-19.7 nmol/L, and that of cord blood 25(OH)D was 40.98+/-18.89 nmol/L. The intake of calcium and vitamin D was uniformly low, although it was higher in urban (1010+/-450 mg/d, 237+/-169 IU/d) than in rural (320+/-210 mg/d, 62+/-66 IU/d) women. Maternal serum 25(OH)D was correlated positively with cord blood 25(OH)D (r=0.94, P<0.01). CONCLUSIONS: There is a high prevalence of vitamin D and calcium insufficiency in pregnant women and neonates in Chengdu even when mothers are compliant with prenatal vitamin supplementation. Supplementation is needed to improve maternal and neonatal vitamin D and calcium nutrition.

[Relationship between Ghrelin and growth hormone secretagogue receptor expression and catch-up growth in rats with intrauterine growth restriction].

OBJECTIVE: To study the relationship between Ghrelin and growth hormone secretagogue receptor (GHSR) expression and the catch-up growth in rats with intrauterine growth restriction (IUGR). METHODS: The rat model of IUGR was established by food restriction during pregnancy. The small for gestational age (SGA) and appropriate for gestational age (AGA) rat pups from the pregnant rats were used as the experimental group. The AGA rat pups from the pregnant rats without food restriction served as the control group. The samples from the stomach fundus and hypothalamus were taken postnatal days 0, 20 and 40. Ghrelin mRNA and GHSR mRNA expression were determined by real-time fluorescence quantitative PCR (real-time FQ-PCR). Ghrelin protein and GHSR protein expression were examined by immunohistochemistry (IHC). RESULTS: At postnatal day 0, both Gherlin mRNA and protein levels in the stomach fundus were significantly higher, while GHSR mRNA expression in the hypothalamus were significantly lower in SGA rats from food restriction group than those in AGA rats from restriction and control groups. At postnatal day 20, the ghrelin protein expression in the stomach of fundus, and GHSR mRNA and protein expression in the hypothalamus in SGA catch-up rats were significantly higher than those in SGA non-catch-up growth rats and AGA rats from the control group. At postnatal day 40, there were no significant differences among SGA catch-up growth rats, SGA non-catch-up growth rats and normal AGA rats. CONCLUSIONS: Ghrelin-GHSR might be involved in the physiological regulation and pathological process in IUGR rats. It is also possibly involved in the regulation of catch-up growth in the early life of SGA rats.

[Effects of different feeding types on the physical growth of infants].

OBJECTIVE: To investigate the effects of different feeding types on the physical growth of infants. METHODS: Infants who visited the children health clinics regularly were recruited for the study. They were classified into breast feeding group, bottle feeding group and mixed feeding group according to the feeding types before 4-months-old. The growth indices were measured and the WHO BMI standards were used to identify overweight and obesity. RESULTS: The body weights and lengths of the male infants with breast feeding were greater than those with other feedings in the first 3 months. The growth of the male infants with bottle feeding began to exceed the other two groups gradually from the 4 month on. The differences of weight and height are statistically significant from 10-12 month and 8-12 month respectively, compared with breast feeding group. The body weights of the female infants with bottle feeding were greater than those with other feedings except for the first month, and the differences were statistically significant from 3 to 12 month (P<0.05). The body lengths of the female infants with bottle feeding were also greater than those with other feedings except for the first two months, and the differences were statistically significant from 4 to 12 month (P<0.05). Before 3-months-old, overweight was more prevalent in the infants with breast feeding than the others. But for the infants 4-months-old and over, overweight was most prevalent in those with bottle feeding (P<0.05). The obesity rate was the highest in the infants with bottle feeding except for the 2-months-old (P<0.05). CONCLUSION: The infants with bottle feeding are exposed to a higher risk of overweight and obesity. Breast feeding may have a potential benefit in preventing infant obesity.