[Vitamin D status in the adolescent: seasonal variations and effects of winter supplementation with vitamin D3]

Effect of Low-Dose Vitamin D Supplementation on Serum 25(OH)D in School Children and White-Collar Workers

OBJECTIVE

Our study aimed to investigate the nutritional vitamin D status of school children aged 9-15 years and white-collar workers in Zhejiang province, and evaluate the efficacy of low-dose-oral vitamin D supplementation in both populations.

METHODS

We conducted a prospective controlled trial during March 2014 to November 2015, comparing the efficacy of vitamin D supplements (400 IU/day) with non-intervention for 18 months in school children aged 9-15 years. Meanwhile, a before-after study was conducted among white-collar workers for 1 year. Serum 25(OH)D concentration was measured at baseline and after vitamin D supplementation, respectively.

RESULTS

At the baseline, 95% of school children and 84% of adult participants had vitamin D deficiency (<20 ng/mL). In school children, no difference was observed between the intervention and control groups with regard to anthropometric data. Serum 25(OH)D concentrations of the school children intervention group, school children control group and white-collar workers were 12.77 ± 3.01 ng/mL, 14.17 ± 3.59 ng/mL and 16.58 ± 3.66 ng/mL at baseline and increased to 17.34 ± 3.78 ng/mL, 18.04 ± 4.01 ng/mL and 17.75 ± 5.36 ng/mL after vitamin D supplementation, respectively. Although, after adjusting for potential confounders, the 400 IU oral vitamin D supplementation increased serum 25(OH)D concentration in school children (β = 0.81, p = 0.0426) as well as in white-collar workers (p = 0.0839), the prevalence of vitamin D deficiency was still very high among school children (79.23% in intervention group and 72.38% in control group) and white-collar workers (76.00%).

CONCLUSIONS

High prevalence of vitamin D deficiency was common in these two study populations. Daily doses of 400 IU oral vitamin D supplementation was not able to adequately increase serum 25(OH)D concentrations. A suitable recommendation regarding the level of vitamin D supplementation is required for this Chinese population.

High prevalence of hypovitaminosis D in Sicilian children affected by growth hormone deficiency and its improvement after 12 months of replacement treatment

PURPOSE

Although the correlation between vitamin D and growth hormone (GH)-insulin-like growth factor 1 (IGF1) axis is documented, as of date, few and conflicting studies have prospectively analyzed vitamin D before and after GH treatment. Our aim was to evaluate as to how the condition of GH deficiency (GHD) or GH treatment influences vitamin D in children.

METHODS

Eighty Sicilian GHD children (M/F 58/22; mean age 10.3 years), grouped according to the season of evaluation in group A (June-September; 41 children) and group B (November-February; 39 children), were evaluated at baseline and after 12 months of GH treatment.

RESULTS

Twenty-eight children (35 %) were vitamin D insufficient and 32 (40 %) deficient at baseline, and lower vitamin D levels were found in group B than in A (17.3 ± 5.3 vs. 31.1 ± 11.1 ng/ml; p < 0.001). A positive correlation between vitamin D and baseline GH levels (p < 0.001) was found. After 12 months, increased vitamin D was found both in all children (34.4 ± 16.4 vs. 24.5 ± 11.1 ng/ml; p = 0.002) and in group A (38.5 ± 14 vs. 31.1 ± 11.1 ng/ml; p < 0.001) and B (30 ± 17.7 vs. 17.3 ± 5.3 ng/ml; p < 0.001). Overall, only 25 (31 %) children remained insufficient and 15 (19 %) deficient, with an increase in prevalence of children with normal levels (p = 0.001).

CONCLUSIONS

Our data demonstrated a very high prevalence of hypovitaminosis D in Sicilian GHD children, with an improvement after 12 months of GH treatment. Vitamin D assessment should therefore be considered routinely in GHD children both at diagnosis and during the follow-up.

[Vitamin D in childhood]

Infantile Nutritional Rickets has disappeared almost completely in France since 1992 as vitamin D enriched formula availability and previous vitamin D supplementation of infants. The search of evocative symptoms of rickets should be a routine procedure in infants, in particular in case of insufficient vitamin D intake i.e. breastfeeding, and the possibility of vitamin D resistant rickets. Hypocalcaemia occurs not only at the first but also the advanced stages of vitamin D deficiency, and may be responsible for severe cardiologic, neurologic or respiratory complications with possibility of infant death. For the young children between 1 and 5 years and for adolescents, vitamin D insufficiency is responsible for poor skeletal mineralization, loss of bone strength, and a reduction of peak of bone mineral mass at the end of puberty. The new Dietary Reference Intakes (DRI, 2011) increased greatly the Recommended Dietary allowances (RDA) from 200 to 600 IU/d (15 μg/d) for individuals from 1 to 70 years of age. These levels are not reached in winter, even in countries, like USA and Canada, where vitamin D milk fortification is mandatory and others like Japan and North-European countries despite high fish consumption. From 1 to 5 years of age and during adolescence, a winter vitamin D3 supplementation is necessary with 80.000 or 100.000 IU periodic loads every 3 months i.e. in November and February. In cases of an underlying risk, i.e. insufficient vitamin D photosynthesis in summertime (dark skin, wearing heavily skin-covering clothes, or several skin diseases), or digestive, renal or nutritional pathologies, use of some drugs, loading dose of 80.000 or 100.000 IU, every 3 months should be administered over the year.

Vitamin D: an overview of its role in skeletal muscle physiology in children and adolescents

Many children may have insufficient serum concentrations of vitamin D, which could prevent optimal muscle development and function. Vitamin D deficiency in animal models results in negative effects on muscle fiber structure and calcium/phosphorus handling, suggesting an integral role of vitamin D in skeletal muscle function. While there is a dearth of data in humans, the available evidence demonstrates a positive association between vitamin D status and muscle function. This review focuses on the important role of vitamin D in muscle function in children and adolescents who live in North American regions where exposure to ultraviolet B radiation is limited and who are thus at increased risk for vitamin D insufficiency. The effects of vitamin D on muscle cell proliferation and differentiation, muscle fiber structure, and calcium and phosphorus handling are discussed. Moreover, the roles of vitamin D and the vitamin D receptor and their genomic and nongenomic actions in muscle function are explored in depth. Future research should aim to establish a vitamin D status consistent with optimal musculoskeletal development and function in young children.

An ecological study of cancer incidence and mortality rates in France with respect to latitude, an index for vitamin D production

France has unexplained large latitudinal variations in cancer incidence and mortality rates. Studies of cancer rate variations in several other countries, as well as in multicountry studies, have explained such variations primarily in terms of gradients in solar ultraviolet-B (UVB) doses and vitamin D production. To investigate this possibility in France, I obtained data on cancer incidence and mortality rates for 21 continental regions and used this information in regression analyses with respect to latitude. This study also used dietary data. Significant positive correlations with latitude emerged for breast, colorectal, esophageal (males), lung (males), prostate, both uterine cervix and uterine corpus, all and all less lung cancer. Although correlations with latitude were similar for males and females, the regression variance for all and all less lung cancer was about twice as high for males than for females. Lung cancer incidence and mortality rates for females had little latitudinal gradient, indicating that smoking may have also contributed to the latitudinal gradients for males. On the basis of the available dietary factor, micro- and macronutrient data, dietary differences do not significantly affect geographical variation in cancer rates. These results are consistent with solar UVB's reducing the risk of cancer through production of vitamin D. In the context of serum 25-hydroxyvitamin D level-cancer incidence relations, cancer rates could be reduced significantly in France if everyone obtained an additional 1,000 IU/day of vitamin D. Many other benefits of vitamin D exist as well.

Le statut en micronutriments des Franciliens. Revue de la littérature

PURPOSE

A review of the literature about micronutrients status of Ile-de-France inhabitants.

CURRENT KNOWLEDGE AND KEY POINTS

During the last decades, substantial changes in the French diet had an impact on micronutrients intake. Over this time, several studies conducted in Ile-de-France showed that a large part of its inhabitants is subject to an increased risk of mild to severe deficiency in one or more micronutrient(s). Teenagers and subjects over 70 years-old are groups at risk for vitamin D deficiency. During the 1980s, iron intake was insufficient in a majority of menstruating women and iron deficiency was common during pregnancy. Vitamin C deficiency is constantly present in homeless people and often associated with an insufficient intake in a number of micronutrients.

FUTURE PROSPECTS AND PROJECTS

Identification of the groups at risk favours a better adequacy of preventive action on micronutrient deficiencies in this population. However, the efficacy of prevention is to be determined. Controlled trials of micronutrients' supplementation may be useful to value the beneficial effects of micronutrient supplementation on the incidence of cardiovascular diseases and cancer.

Rickets

Rickets, once thought vanquished, is reappearing. In some less developed countries it hardly went away. This seminar reviews the effects of genes, stage of development, and environment on clinical expression of the disease. Rickets can be secondary to disorders of the gut, pancreas, liver, kidney, or metabolism; however, it is mostly due to nutrient deficiency and we concentrate on this form. Although calcium deficiency contributes in communities where little cows' milk is consumed, deficiency of vitamin D is the main cause. There are three major problems: the promotion of exclusive breastfeeding for long periods without vitamin D supplementation, particularly for babies whose mothers are vitamin D deficient; reduced opportunities for production of the vitamin in the skin because of female modesty and fear of skin cancer; and the high prevalence of rickets in immigrant groups in more temperate regions. A safety net of extra dietary vitamin D should be re-emphasised, not only for children but also for pregnant women. The reason why many immigrant children in temperate zones have vitamin D deficiency is unclear. We speculate that in addition to differences in genetic factors, sun exposure, and skin pigmentation, iron deficiency may affect vitamin D handling in the skin or gut or its intermediary metabolism.

Sunshine is good medicine. The health benefits of ultraviolet-B induced vitamin D production

Most public health statements regarding exposure to solar ultraviolet radiation (UVR) recommend avoiding it, especially at midday, and using sunscreen. Excess UVR is a primary risk factor for skin cancers, premature photoageing and the development of cataracts. In addition, some people are especially sensitive to UVR, sometimes due to concomitant illness or drug therapy. However, if applied uncritically, these guidelines may actually cause more harm than good. Humans derive most of their serum 25-hydroxycholecalciferol (25(OH)D3) from solar UVB radiation (280-315 nm). Serum 25(OH)D3 metabolite levels are often inadequate for optimal health in many populations, especially those with darker skin pigmentation, those living at high latitudes, those living largely indoors and in urban areas, and during winter in all but the sunniest climates. In the absence of adequate solar UVB exposure or artificial UVB, vitamin D can be obtained from dietary sources or supplements. There is compelling evidence that low vitamin D levels lead to increased risk of developing rickets, osteoporosis and osteomaloma, 16 cancers (including cancers of breast, ovary, prostate and non-Hodgkin's lymphoma), and other chronic diseases such as psoriasis, diabetes mellitus, hypertension, heart disease, myopathy, multiple sclerosis, schizophrenia, hyperparathyroidism and susceptibility to tuberculosis. The health benefits of UVB seem to outweigh the adverse effects. The risks can be minimized by avoiding sunburn, excess UVR exposure and by attention to dietary factors, such as antioxidants and limiting energy and fat consumption. It is anticipated that increasing attention will be paid to the benefits of UVB radiation and vitamin D and that health guidelines will be revised in the near future.

Vitamin D deficiency and associated factors in adolescent girls in Beijing

BACKGROUND

Several locally published reports indicate a high prevalence of vitamin D deficiency among adolescents in China, but no systematic population-based survey has been conducted.

OBJECTIVE

The objective was to determine the prevalence of vitamin D deficiency and to study associated factors in adolescent girls in Beijing.

DESIGN

A cross-sectional study was conducted in a random sample of 1248 Beijing girls aged 12-14 y. Nutrient intakes, ultraviolet light exposure, anthropometric characteristics, physical activity, signs and symptoms of rickets, and plasma concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and calcium were measured and X-rays of the hand and wrist were taken.

RESULTS

The prevalence of clinical vitamin D and calcium deficiency (plasma 25-hydroxyvitamin D <12.5 nmol/L, plasma calcium <2.25 mmol/L, and muscle spasm at least once per week) was 9.4% in winter. The prevalence of subclinical vitamin D deficiency (25-hydroxyvitamin D <12.5 nmol/L) was 45.2% in winter and 6.7% in summer (P < 0.0005). Logistic regression analysis showed that subclinical and clinical vitamin D deficiency in winter were associated with low plasma 25-hydroxyvitamin D concentrations (<12.5 nmol/L) in summer, low calcium intake ( x +/- SD: 280 +/- 48 compared with 440 +/- 61 mg/d), and low plasma calcium concentrations (<2.25 mmol/L) in winter. The odds ratios for these associations were 3.1, 1.5, and 1.5, respectively.

CONCLUSIONS

Subclinical vitamin D deficiency was widespread among Beijing adolescent girls in winter. Low plasma 25-hydroxyvitamin D concentrations in summer, low calcium intake, and low plasma calcium concentrations in winter were the main risk factors for vitamin D deficiency in winter.

[Acute Salmonella typhi meningitis in a 25-day-old newborn infant complicated by obstruction of the sylvian artery]

Acute Salmonella typhi meningitis is rare in neonates, mostly reported from developing countries with poor socioeconomic conditions.

CASE REPORT

A male Caucasian newborn presented with acute Salmonella typhi meningitis at the age of 25 days. His parents had traveled across several African countries under rudimentary hygienic conditions a few months before his birth. Despite early and adapted antibiotic therapy (cefotaxime plus netilmycine), the child developed ischemia in the region of the left sylvian artery.

CONCLUSION

Salmonella meningitis must be considered while dealing with a sick newborn whose mother has traveled across countries with endemic typhoid.

[Prevention of vitamin D deficiency in the child and adolescent. I. Proposal and arguments for use of a decision tree]

A decision-making table, using three questionnaires, is proposed to determine the vitamin D status in children and adolescents. The first questionnaire assesses the vitamin D endogenous synthesis, taking into account the sunlight exposure and the time interval out of the sun. The second questionnaire quantifies the vitamin D dietary intake within three levels: optimal, medium or low. In case of a medium dietary score, a third questionnaire evaluates the daily calcium intake, taking into account the fact that vitamin D metabolism is increased by a low calcium intake (under 400 mg/day). This decision-making table should enable the detection of children and adolescents at risk of vitamin D deficiency and requiring an adapted prophylaxis. Its accuracy will be assessed in prospective surveys.