[Nutritional rickets in childhood: analysis of 62 cases]

Global Health Disparities in Childhood Rickets

Nutritional rickets is a global health problem reflecting both historical and contemporary health disparities arising from racial, ethnic, environmental, and geopolitical circumstances. It primarily affects marginalized populations and can contribute to long-term morbidity. Deficits in bone health in childhood may also contribute to osteomalacia/osteoporosis. Solutions require a global public health approach.

Dietary habits and supplement use in relation to national pregnancy recommendations: data from the EuroPrevall birth cohort

Assessing maternal dietary habits across Europe during pregnancy in relation to their national pregnancy recommendations. A collaborative, multi-centre, birth cohort study in nine European countries was conducted as part of European Union funded EuroPrevall project. Standardised baseline questionnaire data included details of food intake, nutritional supplement use, exposure to cigarette smoke during pregnancy and socio-demographic data. Pregnancy recommendations were collected from all nine countries from the appropriate national organisations. The most commonly taken supplement in pregnancy was folic acid (55.6 % Lithuania-97.8 % Spain) and was favoured by older, well-educated mothers. Vitamin D supplementation across the cohort was very poor (0.3 % Spain-5.1 % Lithuania). There were significant differences in foods consumed in different countries during pregnancy e.g. only 2.7 % Dutch mothers avoided eating peanut, while 44.4 % of British mothers avoided it. Some countries have minimal pregnancy recommendations i.e. Lithuania, Poland and Spain while others have similar, very specific recommendations i.e. UK, the Netherlands, Iceland, Greece. Allergy specific recommendations were associated with food avoidance during pregnancy [relative rate (RR) 1.18 95 % CI 0.02-1.37]. Nutritional supplement recommendations were also associated with avoidance (RR 1.08, 1.00-1.16). Maternal dietary habits and the use of dietary supplements during pregnancy vary significantly across Europe and in some instances may be influenced by national recommendations.

[Vitamin D: pathophysiology and clinical applicability in paediatrics]

Vitamin D has always been associated with calcium -phosphate metabolism, but vitamin D receptors or its metabolites have been found in different body cells, indicating a possible involvement in other physiological mechanisms. Vitamin D deficiency has been associated with an increased risk of infections, autoimmune diseases, diabetes, metabolic syndrome, obesity, asthma and certain neurological diseases such as schizophrenia. Currently there are different techniques for measuring 25 (OH) cholecalciferol in blood, but the results are variable and controversial. It is important to achieve standardization of these techniques to be able to compare the results obtained in different studies. Normal physiological vitamin D levels have not yet been established, but they must be higher than 20 ng/ml (50 nmol/l) in order to perform it physiological function. It is still under discussion on how to achieve these minimum levels. Since the main source of vitamin D is sunlight, we should look for strategies that do not contradict the messages of prevention of skin cancer. In recent years, recommendations for vitamin D intake have changed, involving prophylactic activities carried out in Primary Care. This manuscript reviews the physiology, actions, laboratory determination, desirable levels, and vitamin D intake recommendations, and it highlights many questions raised by new research.

Prophylactic vitamin D in healthy infants: assessing the need

The objective was to evaluate the need for vitamin D prophylaxis in healthy infants. This was a prospective and randomized study performed at primary care clinics. Eighty-eight full-term 1-month-old healthy infants were randomly assigned to receive (n = 41) or not (n = 47) 402 IU/d of vitamin D for 1 year. Primary outcome measures were serum 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) concentrations at 3, 6, and 12 months of age; secondary measures included data on feeding, habitat, season of birth, sun exposure, and physical examination. At 3 and 6 months of age, serum 25OHD levels (±SD) were significantly higher (P < .001) in the prophylaxis group. In the group without prophylaxis, serum 25OHD increased with age; and breast-fed infants aged 3 months had the lowest value (20.2 ± 9.4 ng/mL), which was significantly (P = .001) lower than that of formula-fed infants (35.0 ± 9.7 ng/mL). The PTH levels were not influenced by the prophylaxis or feeding. No influence of either the habitat or season of birth on serum 25OHD concentrations was demonstrated. No infant had clinical signs of vitamin D deficiency. Serum 25OHD and PTH concentrations were weakly but significantly correlated (r = -0.29, P = .009) at 3 months of age. Healthy infants without vitamin D prophylaxis had lower circulating concentrations of 25OHD at 3 and 6 months of age, the lowest value being found in 3-month breast-fed infants. The clinical relevance of these findings is probably negligible because serum 25OHD levels spontaneously increased with age and were not associated with high serum PTH. Clinical manifestations of rickets were not observed.

Prevalence of vitamin D deficiency among Turkish, Moroccan, Indian and sub-Sahara African populations in Europe and their countries of origin: an overview

Vitamin D status of nonwestern immigrants in Europe was poor. Vitamin D status of nonwestern populations in their countries of origin varied, being either similar to the immigrant populations in Europe or higher than in European indigenous populations. Vitamin D concentrations in nonwestern immigrant populations should be improved.

PURPOSE

The higher the latitude, the less vitamin D is produced in the skin. Most European countries are located at higher latitudes than the countries of origin of their nonwestern immigrants. Our aim was to compare the serum 25-hydroxyvitamin D (25(OH)D) concentration of nonwestern immigrant populations with those of the population in their country of origin, and the indigenous population of the country they migrated to.

METHODS

We performed literature searches in the "PubMed" and "Embase" databases, restricted to 1990 and later. The search profile consisted of terms referring to vitamin D or vitamin D deficiency, prevalence or cross-sectional studies, and countries or ethnicity. Titles and abstracts were reviewed to identify studies on population-based mean serum 25(OH)D concentrations among Turkish, Moroccan, Indian, and sub-Sahara African populations in Europe, Turkey, Morocco, India, and sub-Sahara Africa.

RESULTS

The vitamin D status of immigrant populations in Europe was poor compared to the indigenous European populations. The vitamin D status of studied populations in Turkey and India varied and was either similar to the immigrant populations in Europe (low) or similar to or even higher than the indigenous European populations (high).

CONCLUSIONS

In addition to observed negative consequences of low serum 25(OH)D concentrations among nonwestern populations, this overview indicates that vitamin D status in nonwestern immigrant populations should be improved. The most efficacious strategy should be the subject of further study.

Rickets in the Middle East: role of environment and genetic predisposition

CONTEXT

The Middle East has a high incidence of rickets, and it is also common in Europe-dwelling children of Middle Eastern origin.

OBJECTIVE

The objective of the study was to explore the mechanisms leading to rickets in children of the Middle East.

DESIGN AND SETTING

We conducted a prospective study in 98 rachitic and 50 controls (aged 6 months to 4 yr) from university and community outpatient hospitals in Egypt and Turkey.

MAIN OUTCOME MEASURES

We collected epidemiological, maternal, nutritional, radiographic, and biochemical parameters; markers of bone turnover; and vitamin D receptor (VDR) gene polymorphisms.

RESULTS

Epidemiological factors had a key role in pursuit of rickets; Egyptian and Turkish patients had lower (P < 0.01) dietary calcium intake than controls and the recommended dietary intakes, and serum 25-hydroxyvitamin D levels were reduced in patients, the difference with controls being significant (P < 0.001) only in Turkey, although rickets was more severe in Egypt as determined by the x-ray score (P < 0.05). In Turkey, the F VDR allele frequency was significantly (P < 0.05) increased in patients. The BB VDR genotype was associated with lower serum 25-hydroxyvitamin D levels in both patients and controls and with severity of rickets.

CONCLUSIONS

In Turkey most patients had vitamin D deficiency, whereas in Egypt they had mostly calcium insufficiency combined with vitamin D deficiency. In this environ, VDR genotypes may predispose to rickets by increased frequency of the F allele. The unique environs and genetic predisposition have to be accounted for in the design of preventive measures, rather than using European or American recommended dietary intake for calcium and vitamin D.

Niveles de 25-hidroxivitamina D en lactantes. Relación con la lactancia materna

OBJECTIVE

To determine the prevalence of subclinical vitamin D deficiency among infants in Valencia, Spain (latitude 39.5 degrees N) and its relation with breast- feeding.

MATERIAL AND METHODS

Serum levels of calcium, phosphate, alkaline phosphatase, 25-hydroxyvitamin D (25-OHD) and intact parathyroid hormone (PTH) were measured in 60 term infants aged between 1 and 6 months (mean age: 3.9 months), with no known bone, gastrointestinal or renal disease (33 exclusively breast-fed, 27 bottle-fed). Data on vitamin D supplementation and weekly direct sunlight exposure were also gathered.

RESULTS

All infants had normal serum calcium, phosphate and PTH levels. Five infants (8.3 %) had 25-OHD levels < 10 ng/ml (lower limit of normality) and all of these infants were breast-fed (15.1 % of the group). None of these five infants received vitamin D supplementation. Infants with vitamin D deficiency had slightly elevated serum alkaline phosphatase. Only 48 % of breast-fed infants received regular vitamin D supplementation. The mean serum 25-OHD concentration of breast-fed infants in winter (16.8 ng/ml) was significantly lower than that in bottle-fed infants in summer (23.6 ng/ml, p < 0.05).

CONCLUSIONS

In breast-fed infants, the association of limited sunshine exposure and poor dietary vitamin D supplementation confers a high risk of subclinical vitamin D deficiency, even in regions with a temperate climate.

Nutritional rickets: deficiency of vitamin D, calcium, or both?

Nutritional rickets remains a public health problem in many countries, despite dramatic declines in the prevalence of the condition in many developed countries since the discoveries of vitamin D and the role of ultraviolet light in prevention. The disease continues to be problematic among infants in many communities, especially among infants who are exclusively breast-fed, infants and children of dark-skinned immigrants living in temperate climates, infants and their mothers in the Middle East, and infants and children in many developing countries in the tropics and subtropics, such as Nigeria, Ethiopia, Yemen, and Bangladesh. Vitamin D deficiency remains the major cause of rickets among young infants in most countries, because breast milk is low in vitamin D and its metabolites and social and religious customs and/or climatic conditions often prevent adequate ultraviolet light exposure. In sunny countries such as Nigeria, South Africa, and Bangladesh, such factors do not apply. Studies indicated that the disease occurs among older toddlers and children and probably is attributable to low dietary calcium intakes, which are characteristic of cereal-based diets with limited variety and little access to dairy products. In such situations, calcium supplements alone result in healing of the bone disease. Studies among Asian children and African American toddlers suggested that low dietary calcium intakes result in increased catabolism of vitamin D and the development of vitamin D deficiency and rickets. Dietary calcium deficiency and vitamin D deficiency represent 2 ends of the spectrum for the pathogenesis of nutritional rickets, with a combination of the 2 in the middle.