[Prevention of vitamin D deficiency in adolescents and pre-adolescents. An interventional multicenter study on the biological effect of repeated doses of 100,000 IU of vitamin D3].

Unlabelled: Recent studies have shown a high prevalence of calcium and vitamin D deficiencies in adolescents. The aim of this present study was to follow the changes in calcium status and 25 hydroxyvitamin D (25[OH]D) and parathyroid hormone (iPTH) levels during winter in preadolescents and adolescents from four university hospitals in northern France.

Subjects And Methods: Two groups of teenagers and adolescents (range: 10-15 years) were followed from October 1996 to June 1997.

Association between vitamin D receptor gene polymorphism and sex-dependent growth during the first two years of life.

An association between vitamin D receptor (VDR) gene polymorphisms and bone mass variance has been observed in adult populations. To analyze possible association between VDR genotype and growth, we studied 589 healthy infants who were homogeneous for age, diet, and vitamin D status. The Bsm I, TaqI, and ApaI alleles' frequencies and genotypes were similar to those reported for Caucasian populations.

Subclinical vitamin D deficiency in neonates: definition and response to vitamin D supplements.

To determine the biological criteria for neonatal vitamin D deficiency, serum 25-hydroxyvitamin D (calcidiol), parathyroid hormone (PTH), calcium, phosphates, and alkaline phosphatase (ALP) activity were measured during the winter-spring period in 80 healthy neonates and their mothers 3-6 d after delivery. A longitudinal 3-mo survey of the serum biology of 52 of these neonates consuming formula was also performed to test the influence of their neonatal vitamin D status on the effects of two oral ergocalciferol supplements (500 and 1000 IU or 12.5 and 25 micrograms/d).

[Fortified milk and supplements of oral vitamin D. Comparison of the effect of two doses of vitamin D (500 and 1,000 UI/d) during the first trimester of life].

Background: Administration of oral vitamin D supplements has been the usual strategy used in France for the prevention of rickets. But this strategy needs reevaluation since the fortification of infant formulas with vitamin D is authorized in this country. We report the effects of oral daily supplements of vitamin D on the calcium metabolism and vitamin D status of infants receiving or not fortified milk during the first trimester of life.

Serum osteocalcin regulation in protein-energy malnourished children.

To evaluate bone turnover changes occurring during protein-energy malnutrition, serum osteocalcin, a marker of bone formation, has been studied in healthy control, stunted, and severely malnourished (kwashiorkor and marasmus) Senegalese children. Serum osteocalcin levels were dramatically reduced in stunted, kwashiorkor, and marasmic children compared with control children. In addition serum osteocalcin levels of control children living in Senegal were lower (-46%) than those of African children living in France.

[Vitamin D and pubertal maturation. Value and tolerance of vitamin D supplementation during the winter season].

Background: In France, several cases of vitamin D-deficiency rickets among adolescents have been reported, but no prophylaxis measure has been systematically recommended at this age. The aim of this study was to measure 25-hydroxyvitamin D (25-(OH)D) levels and to search for biological signs of vitamin D deficiency during adolescence. Moreover, the effects of a unique oral dose of 100,000 IU of vitamin D3, given during the winter, were analysed.

Vitamin D prophylaxis during infancy: comparison of the long-term effects of three intermittent doses (15, 5, or 2.5 mg) on 25-hydroxyvitamin D concentrations.

Serum 25-hydroxyvitamin D [25(OH)D], calcium, phosphorus, and alkaline phosphatase activities were measured from birth to 6-9 mo of age in 60 healthy neonates to assess the effectiveness and potential toxicity of three intermittent oral doses of cholecalciferol. Two weeks after a first dose of 15, 5, or 2.5 mg, 25(OH)D concentrations reached 307 +/- 160, 150 +/- 55, and 92 +/- 42 nmol/L, respectively.

[Effects of sunlight exposure on vitamin D status in pregnant women in France].

The concentration of 25-(OH)D in the blood were measured in 61 pregnant women between the ages of 16 and 45 who were living in three towns that had different amounts of sun (Lyon, Chambery, Nice). The reason for doing this was to find out the influence of exposure or non-exposure to sun on the vitamin D status of these women. A subclinical lack of vitamin D was found in a number of women where ever they lived, seemingly linked to too little exposure to sun (5% of women exposed to sunshine and 59% of women who were not exposed to sunshine had concentrations of 25-(OH)D (less than 10 ng/ml).

[Vitamin D supplementation in institutionalized elderly. Effects of vitamin D3 (100,000 IU) orally administered every 3 months on serum levels of 25-hydroxyvitamin D].

A clinical trial carried out during the autumn/winter season in 46 institutionalized elderly subjects (35 women, 11 men) (group mean age = 83 +/- 2 years) revealed a severe deficiency in vitamin D in these subjects (25-hydroxyvitamin D level less than or equal to 3 ng/ml). After oral administration of 100,000 IU of vitamin D3, an increase in 25-hydroxyvitamin D levels above the 10 ng/ml threshold was observed and maintained for three months. A second dose, administered after 3 months, made it possible to sustain this level.

[Administration of a single dose of 100,000 U.I. of vitamin D3 in the pregnant woman in winter. The effect on blood calcium level of the newborn infant].

Serum levels of 25-hydroxyvitamin D [25-(OH)D], calcium, phosphate and alkaline phosphatase activity were measured between December and July in 110 pregnant women during the last trimester of pregnancy, and in their infants on the fifth day of life. This study showed a fall, during spring, below 6 ng/ml, of the maternal 25-(OH)D concentration at the time of delivery, and a fall of the 25-(OH)D and calcium concentrations in newborns. The existence of a positive correlation between calcium and 25-(OH)D levels in the newborns suggests that the low calcium concentrations found in the infants born in spring is related to a vitamin D deficiency of the infant and therefore of the mother.