Le rachitisme symptomatique de l’adolescent

Vitamin D in Adolescents: A Systematic Review and Narrative Synthesis of Available Recommendations

PURPOSE

Practical guidelines help clinicians make their preventive and therapeutic choices and improve care management. Our purpose was to collect and synthesize available recommendations concerning vitamin D in adolescents (aged 10-19 years).

METHODS

We searched PubMed, EMBASE, and Cochrane databases from inception to February 5, 2019, for guidance published by different professional associations and governments. We also searched the reference lists of identified recommendations and explored the gray literature using Web search engines. We organized documents by theme: dietary requirements, thresholds, prophylactic supplementation, and treatment of deficiency.

RESULTS

A total of 32 documents were identified. Most of them targeted the general population and not specifically the age group of adolescents. There is a general agreement that adolescents should not have serum 25-hydroxyvitamin D concentrations below 25-30 nmol/L to avoid poor bone health. However, there is lack of consensus on the optimal concentration to aim for, levels varying between 25 nmol/L and 150 nmol/L. Adequate nutritional requirements of vitamin D are also subject to debate with values ranging between 200 IU/d and 1,000 IU/d. The upper tolerable intake is estimated at 4,000 IU/d by all study groups. Certain associations recommend routine vitamin D supplementation in adolescents. The recommended daily preventive doses vary between 400 IU and 4,000 IU, depending on season, skin pigmentation, sun exposure, consumption of vitamin D-fortified foods, body mass index, and coexistence of certain medical conditions. In case of deficiency, different therapeutic regimens of oral vitamin D are proposed depending on the presence of illness and/or the baseline serum 25-hydroxyvitamin D concentrations. Duration of the treatment varies between 4 weeks and 3 months. A maintenance dose is generally recommended after treatment.

CONCLUSIONS

At present, there is no consensus among the different societies about vitamin D needs during adolescence. Stronger, evidence-based guidance is needed to inform clinical practice.

Vitamin D: still a topical matter in children and adolescents. A position paper by the Committee on Nutrition of the French Society of Paediatrics

The aims of the present position paper by the Committee on Nutrition of the French Society of Paediatrics were to summarize the recently published data on vitamin D in infants, children and adolescents, i.e., on metabolism, physiological effects, and requirements and to make recommendations on supplementation after careful review of the evidence. Scientific evidence indicates that calcium and vitamin D play key roles in bone health. The current evidence, limited to observational studies, however, does not support other benefits for vitamin D. More targeted research should continue, especially interventional studies. In the absence of any underlying risk of vitamin D deficiency, the recommendations are as follows: pregnant women: a single dose of 80,000 to 100,000 IU at the beginning of the 7th month of pregnancy; breastfed infants: 1000 to 1200 IU/day; children less than 18 months of age, receiving milk supplemented with vitamin D: an additional daily dose of 600 to 800 IU; children less than 18 months of age receiving milk not supplemented with vitamin D: daily dose of 1000 to 1200 IU; children from 18 months to 5 years of age: 2 doses of 80,000 to 100,000 IU every winter (November and February). In the presence of an underlying risk of vitamin D deficiency (dark skin; lack of exposure of the skin to ultraviolet B [UVB] radiation from sunshine in summer; skin disease responsible for decreased exposure of the skin to UVB radiation from sunshine in summer; wearing skin-covering clothes in summer; intestinal malabsorption or maldigestion; cholestasis; renal insufficiency; nephrotic syndrome; drugs [rifampicin; antiepileptic treatment: phenobarbital, phenytoin]; obesity; vegan diet), it may be justified to start vitamin D supplementation in winter in children 5 to 10 years of age as well as to maintain supplementation of vitamin D every 3 months all year long in children 1 to 10 years of age and in adolescents. In some pathological conditions, doses of vitamin D can be increased. If necessary, the determination of 25(OH) vitamin D serum concentration will help determine the level of vitamin D supplementation.

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.

[Administration of a single Winter oral dose of 200,000 IU of vitamin D3 in adolescents in Normandy: evaluation of the safety and vitamin D status obtained]

Adolescence, a period of growth and acquisition of bone mass, requires adequate calcium and vitamin D intake. This study was designed to assess the impact of a single loading dose of 200,000 IU of vitamin D(3) on the winter vitamin D status of healthy adolescents. Vitamin D status was assessed by 25-OH-D levels before, 3 weeks, and 3 months after this single dose, and safety was assessed by serum calcium and PTH and urinary calcium excretion in random samples from 27, 23, and 17 healthy adolescents derived from the same institution. The 25-OH-D peak value 2 weeks after the vitamin D supplement of 71-129 nmol/l (mean, 96 nmol/l), and a residual level at 3 months of 29-83 nmol/l (mean, 57 nmol/l) serum calcium and urinary calcium excretion expressed by the calcium/creatinine ratio were normal and stable at 2 weeks and 3 months, remaining less than 0.5 for the calcium/creatinine ratio. This simple measure, ensuring good compliance during adolescence, ensures optimal winter vitamin D status with no signs of overload.

Nutritional rickets: still a problem for the pediatric population

Rickets is a mineralization disorder of the growing bone. Nutritional rickets is still prevalent in many parts of the developing world and is re-emerging in developed countries. Although vitamin D deficiency plays a central role in the pathogenesis of this disease, calcium deficiency and genetic factors may also cause or contribute to the development of rickets. This review will focus on the classical form of nutritional rickets, in other words, vitamin D-deficiency rickets. The epidemiology, ethiopathogenesis, risk factors, clinical picture, diagnosis, treatment and prevention of nutritional rickets are reviewed.

Early adolescent nutritional rickets

PURPOSE

To evaluate early adolescents with nutritional rickets and their responses to treatment.

METHODS

203 adolescents (aged 10 to 13 years) presenting with clinical features of lower-limb deformity, carpopedal spasm, joint swelling, a significant limp, or non-traumatic joint pain were screened for nutritional rickets. Multi-specialty examinations were performed. Family size, number of earning members, number and gender of children, preference for vegetarian food, composition of the meals, and the amount of milk consumed in a day were recorded. Radiographs of wrists, knees, ankles, and pelvis, as well as serum calcium, phosphate, and alkaline phosphatase levels were evaluated. The diagnosis of nutritional rickets was made based on a combination of clinical, radiological, and biochemical criteria, and confirmed by the responses to treatment. Children with nutritional rickets were treated by a single large intramuscular dose of vitamin D (600,000 IU) along with oral calcium and supplementary vitamin D as well as advice on diet and sunlight exposure.

RESULTS

40 females and 11 males were diagnosed as having nutritional rickets. 65% presented with bilateral knee pain with aggravation at night, 37% presented with lower-limb deformity, 24% had joint swelling especially at the wrist and ankle, 6% had a significant limp and walked with an antalgic gait secondary to pathological fractures. No patient reported carpopedal spasm. All patients had rachitic changes on radiographs in some but not all bones (100% in the ulna, 45% in the radius, 37% in the upper tibia, 37% in the lower fibula and 22% in the lower tibia). Three patients had pathological fractures. 55% had hypocalcaemia, 41% had hypophosphataemia and 100% had raised serum alkaline phosphatase levels. The mean time for biochemical resolution was 12 (range, 3-24) weeks. For radiological resolution it was 5 (range, 2-6) months, with the lower end of ulna being last to resolve.

CONCLUSIONS

Radiographs of the lower end of ulna and serum alkaline phosphatase levels can be used as a screening and monitoring tool for nutritional rickets in early adolescents. There may be a high prevalence of subclinical vitamin-D deficiency in our adolescent population.

Hypophosphatasia may lead to bone fragility: don't miss it

Hypophosphatasia is an inheritable disorder characterised by defective bone mineralisation due to the impaired activity of tissue-non-specific alkaline phosphatase (AP). Clinical presentation ranges from stillbirth without mineralised bone to pathological fractures in late adulthood. During childhood, the main manifestations include rickets, growth delay and dental problems. Fractures and bone pain usually characterise the adult form. A 9-year-old girl was referred for repetitive fractures after minimal trauma. She had normal growth, normal sclerae, no rickets and minimal dental abnormalities. Her sister had also presented fractures. The proband, her sister and mother had low total and bone-specific AP levels and E435K mutation in exon 12 of the liver/bone/kidney AP gene. Low AP levels must lead to genetic analysis. Bone fragility and repetitive fractures may be symptoms of hypophosphatasia in childhood, which must not be neglected. Associated factors such as vitamin D or calcium deficiency must be prevented. In conclusion, hypophosphatasia must not be forgotten as an aetiological factor of repetitive fractures or bone pain in children and AP activity should be checked accurately.

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.

Nutritional rickets: nature or nurture?

Rickets is a mineralization disorder of the growing bone. Nutritional rickets is still prevalent in many parts of the world. Although vitamin D deficiency plays a central role in the pathogenesis of this disease, calcium deficiency and genetic factors may also cause or contribute to the development of rickets. This review will focus on the classical form of nutritional rickets: vitamin D deficiency rickets. Epidemiology, ethiopathogenesis, risk factors, the current clinical picture, diagnosis, treatment and prevention of nutritional rickets will be reviewed.

Statut calcique et vitaminique D des enfants d'âge préscolaire. À propos d'une enquête pratiquée en région rouennaise

Few data are available regarding calcium and vitamin D intake in toddlers, despite a remaining high growth velocity. Therefore, a study was carried out in the Rouen geographical area where the sunshine is limited. It appears that a great majority of the children studied (9/10) received plain milk, and subsequently only small quantities of vitamin D or calcium enriched milk. Nevertheless, 12% of primarily 4 to 6 year-old children do not received daily minimum requirements, and 6% of them had vitamin D insufficiency, which was demonstrated by 25OHD plasma concentrations. These concentrations declined from 18 months to 6 years old were related to discontinuation in vitamin D supplements. A great variability was observed in vitamin D supplementation as no official recommendations were followed. Modalities of this supplementation should be reconsidered.