Prevalence and risk factors for vitamin D deficiency among healthy infants and young children in Sacramento, California

25-hydroxy Vitamin D Levels in Pediatric Asthma Patients and its Link with Asthma Severity

Aim

Although the relationship between 25-hydroxy (25-OH) vitamin D and asthma is known, it is unknown if 25-OH vitamin D levels are correlated with asthma severity in pediatric patients. The aim of this study was to compare the blood 25-OH vitamin D levels of asthma patients and healthy control groups and to evaluate any correlation between asthma severity and blood 25-OH vitamin D levels in pediatric asthma patients.

Methods

This is a cross-sectional study which shows the 25-OH vitamin D levels of asthma patients and compared to healthy controls followed by a tertiary pediatric clinic. We investigated the effect of 25-OH vitamin D levels on the severity of asthma. The severity of asthma was determined mainly by the duration of asthma diagnosis, a number of attacks in the previous year, anti-inflammatory medication usage in a previous year, atopy presence in the family, skin prick test positivity, and immunoglobulin E (IgE) levels of asthma patients.

Results

Compared with control groups, asthma patients had significantly lower 25-OH vitamin D, calcium (Ca) levels, and higher number of patients who had a 25-OH vitamin D deficiency, (p<0.0001, p<0.0001, p<0.0001, respectively). We found a correlation between blood 25-OH vitamin D levels and force expiratory capacity in one second (FEV1) and forced vital capacity (FVC) respectively (p< 0.001, r=0.512), (p< 0.001, r=0.513). There was an association between FEV1, FVC and blood 25-OH vitamin D levels in terms of deficient levels (<20 ng/mL) or insufficient levels (≥20 and <30 ng/mL) (p<0.001, r=0.459), (p< 0.001, r=0.450), respectively.

Conclusions

The 25-OH vitamin D levels were lower in pediatric asthma patients with worse spirometry results. Effects of Vitamin D supplementation need to be evaluated by well-designed studies.

Vitamin D Insufficiency and Its Association with Biochemical and Anthropometric Variables of Young Children in Rural Southwestern China

BACKGROUND

With recognition of the important roles of Vitamin D (VitD) in various physiological processes, increasing attention has been drawn to the status of VitD in early life. However, the VitD status of young children and the related factors in rural areas of Southwestern China remain unclear. This study aimed to explore VitD status and its seasonal variation in 18-month-old children living in rural Southwestern China. The association of VitD with biochemical and anthropometric variables was also investigated.

METHODS

A total of 177 18-month-old children in a rural area of Yunnan Province, Southwestern China, were enrolled. Serum concentrations of 25-hydroxy Vitamin D (25(OH)D) were measured through high-performance liquid chromatogram-tandem mass spectrometry. Parathyroid hormone (PTH) levels were measured with a chemiluminescence assay. Serum concentrations of calcium, phosphorus, and alkaline phosphatase (ALP) were also measured. Anthropometric data and the outdoor activity time of each participant were collected.

RESULTS

The serum 25(OH)D concentration was 26.61 ± 7.26 ng/ml; concentrations lower than 30 ng/ml accounted for 70.6% of the participants and concentrations lower than 20 ng/ml accounted for 16.4%. The level of serum 25(OH)D was not significantly different among four seasons (P >0.05). A positive relationship was found between 25(OH)D concentration and the time of outdoor activities (r = 0.168, P < 0.05). Serum PTH concentration was negatively correlated with 25(OH)D concentration (r = -0.163, P < 0.05). A positive relationship was found between the serum concentrations of 25(OH)D and calcium (r = 0.154, P < 0.05). No significant association was observed between 25(OH)D and ALP, phosphorus, or anthropometric variables.

CONCLUSIONS

The prevalence of VitD insufficiency is high among young children in the rural Southwestern China regardless of the seasons. VitD supplementation is still essential to maintain VitD sufficiency for children living in rural area.

Vitamin D supplementation for preventing infections in children under five years of age

BACKGROUND

Vitamin D is a micronutrient important for bone growth and immune function. Deficiency can lead to rickets and has been linked to various infections, including respiratory infections. The evidence on the effects of supplementation on infections in children has not been assessed systematically.

OBJECTIVES

To evaluate the role of vitamin D supplementation in preventing pneumonia, tuberculosis (TB), diarrhoea, and malaria in children under five years of age. This includes high-, middle-, and low-income countries.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library, MEDLINE, EMBASE, LILACS, the WHO International Clinical Trials Registry Platform (ICTRP; http://www.who.int/ictrp/en/) , ClinicalTrials.gov and the ISRCTN registry (http://www.isrctn.com/) up to 16 June 2016.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated preventive supplementation of vitamin D (versus placebo or no intervention) in children under five years of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts, extracted the data, and assessed the risk of bias of included trials.

MAIN RESULTS

Four trials met the inclusion criteria, with a total of 3198 children under five years of age, and were conducted in Afghanistan, Spain, and the USA. Prevalence of vitamin D deficiency varied widely in these populations (range: 73.1% in Afghanistan, 10 to 12% in USA, and 6.2% in Spain). The included trials evaluated mortality (two trials), pneumonia incidence (two trials), diarrhoea incidence (two trials), hospitalization (two trials), and mean serum vitamin D concentrations (four trials).We do not know whether vitamin D supplementation impacts on all-cause mortality because this outcome was underpowered due to few events (risk ratio (RR) 1.43, 95% confidence interval (CI) 0.54 to 3.74; one trial, 3046 participants, low quality evidence).For pneumonia, episodes of 'radiologically confirmed' first or only episode of pneumonia were little different in the supplemented and unsupplemented group (Rate Ratio: 1.06, 95% confidence interval (CI) 0.89 to 1.26; two trials, 3134 participants, moderate quality evidence), and similarly for children with confirmed or unconfirmed pneumonia (RR 0.95, 95% CI 0.87 to 1.04; one trial, 3046 participants). In these two trials there were no obvious differences between supplemented and unsupplemented children regarding episodes of diarrhoea.In the single large trial from Afghanistan, the trial authors reported that vitamin D supplementation was associated with an increase in repeat episodes of pneumonia confirmed by chest radiograph (RR 1.69, 95% CI 1.28 to 2.21; one trial, 3046 participants), but not reflected in the outcome of confirmed or unconfirmed pneumonia (RR 1.06, 95% CI 1.00 to 1.13; one trial, 3046 participants).For hospital admission measured in one small trial, there was no difference detected (RR 0.86, 95% CI 0.20 to 3.62; one trial, 88 participants; very low quality evidence).The mean serum vitamin D concentrations were higher in supplemented compared to unsupplemented children at the end of supplementation (MD 7.72 ng/mL, 95% CI 0.50 to 14.93; four trials, 266 participants, low quality evidence). These results were driven primarily by two smaller trials with large magnitudes of effect. In the other two bigger trials, serum vitamin D concentrations were elevated in the intervention group for most of the trial duration but not at the end of supplementation. This may be due to time elapsed at measurement from the last dose, incomplete compliance, or increased need of vitamin D with infant age.We did not find any trial that reported on the incidence of TB, malaria or febrile illness, duration of pneumonia, duration of diarrhoea, severity of infection, and cause-specific mortality (due to TB, diarrhoea, or malaria).

AUTHORS' CONCLUSIONS

Evidence from one large trial did not demonstrate benefit of vitamin D supplementation on the incidence of pneumonia or diarrhoea in children under five years. To our knowledge, trials that evaluated supplementation for preventing other infections, including TB and malaria, have not been performed.

Determinants of 25-Hydroxyvitamin D Concentrations in Infants and Toddlers

BACKGROUND

Resurgence of rickets and recognition of excessive prevalence of hypovitaminosis D among all age groups in the western hemisphere have refocused attention on vitamin D nutrition.

OBJECTIVE

To examine the prevalence of hypovitaminosis D [25-hydroxyvitamin D [25(OH)D] <30ng/mL] and characterize the determinants of 25(OH)D concentrations in 8- to 24-month-old healthy infants and toddlers living in Pittsburgh, Pennsylvania.

METHODS

Serum 25(OH)D concentrations were measured and dietary intake of vitamin D, mode of feeding, summertime sun exposure characteristics, and skin color (sun-reactive skin type and melanin index) were assessed.

RESULTS

A total of 111 healthy 8- to 24-month-old children (mean age [±SD] 14.4 [±3.5] months; male, 51%; black, 67%) were studied. Serum 25(OH)D concentration was <30 ng/mL in 16% (n=18) of the children. Median (interquartile) 25(OH)D concentration was lower in children who were ≥ 13 months vs. <13 months of age [35 (31, 40.5) vs. 40 (35.8, 44.3) ng/mL, p=0.013]; with sun-reactive skin type IV and V vs. I, II, and III [36 (31, 41) vs. 44 (36.5, 48.5) ng/mL, p=0.001]; and examined during fall/winter vs. spring/summer [35.5 (32.5, 38.5) vs. 39 (32.5, 44) ng/mL, p=0.05]. Age and skin type were significant independent predictors of 25(OH)D.

CONCLUSIONS

Concentrations of 25(OH)D tend to be lower in infants and toddlers during fall/winter, and in children who are older (≥13 months vs. <13 months of age) and have darker skin tone. Benefits of enhancement of 25(OH)D concentrations during fall/winter and in children with higher sun-reactive skin type need further exploration.

Vitamin D and skeletal health in infancy and childhood

During growth, severe vitamin D deficiency in childhood can result in symptomatic hypocalcaemia and rickets. Despite the suggestion from some studies of a secular increase in the incidence of rickets, this observation may be driven more by changes in population demographics than a true alteration to age, sex and ethnicity-specific incidence rates; indeed, rickets remains uncommon overall and is rarely seen in fair-skinned children. Additionally, the impact of less severe vitamin D deficiency and insufficiency has received much interest in recent years, and in this review, we consider the evidence relating vitamin D status to fracture risk and bone mineral density (BMD) in childhood and adolescence. We conclude that there is insufficient evidence to support the suggestion that low serum 25-hydroxyvitamin D [25(OH)D] increases childhood fracture risk. Overall, the relationship between 25(OH)D and BMD is inconsistent across studies and across skeletal sites within the same study; however, there is evidence to suggest that vitamin D supplementation in children with the lowest levels of 25(OH)D might improve BMD. High-quality randomised trials are now required to confirm this benefit.

Vitamin D insufficiency among hospitalised children in the Northern Territory

AIM

Acute lower respiratory infections (ALRIs) are the most common reason for hospitalisation of young children in the Northern Territory of Australia. International studies have linked vitamin D deficiency with increased risk of ALRI in paediatric populations, but this has not been explored in tropical regions such as the Top End of the Northern Territory. The aim of this study is to determine the prevalence of vitamin D insufficiency among children hospitalised with ALRI in the Northern Territory.

METHODS

Vitamin D serum metabolite (25OHD3) levels were retrospectively measured using liquid chromatography-mass spectrometry in 74 children (64% male; 57% Indigenous) aged less than 3 years admitted to Royal Darwin Hospital in the Northern Territory of Australia between May 2008 and May 2010.

RESULTS

There were 44 (59%) ALRI-classified hospitalisations and 30 (41%) non-ALRI-classified hospitalisations. The most common ALRI diagnoses were bronchiolitis (n = 22, 30%) and pneumonia (n = 21, 28%), whereas the most common non-ALRI diagnosis was gastroenteritis (n = 20, 27%). Overall, 24/74 (32%) children had 25OHD3 levels <75 nmol/L (insufficiency). For children hospitalised with ALRI, 23% (10/44) had vitamin D insufficiency compared with 47% (14/30) among children hospitalised for other reasons (odds ratio 0.34, 95% confidence interval 0.11-1.03; P = 0.043). Twelve of the 20 (60%) children hospitalised for gastroenteritis had vitamin D insufficiency.

CONCLUSIONS

Vitamin D insufficiency was observed in almost one-third of these hospitalised children. Children hospitalised with an ALRI were less likely to have vitamin D insufficiency compared with children hospitalised for other conditions (predominantly gastroenteritis).

Vitamin D during pregnancy and infancy and infant serum 25-hydroxyvitamin D concentration

OBJECTIVE

To determine the vitamin D dose necessary to achieve serum 25-hydroxyvitamin D (25(OH)D) concentration ≥ 20 ng/mL during infancy.

METHODS

A randomized, double-blind, placebo-controlled trial in New Zealand. Pregnant mothers, from 27 weeks' gestation to birth, and then their infants, from birth to age 6 months, were randomly assigned to 1 of 3 mother/infant groups: placebo/placebo, vitamin D3 1000/400 IU, or vitamin D3 2000/800 IU. Serum 25(OH)D and calcium concentrations were measured at enrollment, 36 weeks' gestation, in cord blood, and in infants at 2, 4, and 6 months of age.

RESULTS

Two-hundred-and-sixty pregnant women were randomized. At enrollment, the proportions with serum 25(OH)D ≥ 20 ng/mL for placebo, lower-dose, and higher-dose groups were 54%, 64%, and 55%, respectively. The proportion with 25(OH)D ≥ 20 ng/mL was larger in both intervention groups at 36 weeks' gestation (50%, 91%, 89%, P < .001). In comparison with placebo, the proportion of infants with 25(OH)D ≥ 20 ng/mL was larger in both intervention groups to age 4 months: cord blood (22%, 72%, 71%, P < .001), 2 months (50%, 82%, 92%, P < .001), and 4 months (66%, 87%, 87%, P = .004), but only in the higher-dose group at age 6 months (74%, 82%, 89%, P = .07; higher dose versus placebo P = .03, lower dose versus placebo P = .21).

CONCLUSIONS

Daily vitamin D supplementation during pregnancy and then infancy with 1000/400 IU or 2000/800 IU increases the proportion of infants with 25(OH)D ≥ 20 ng/mL, with the higher dose sustaining this increase for longer.

Maternal vitamin D supplementation to meet the needs of the breastfed infant: a systematic review

Maternal vitamin D insufficiency during lactation, related to lack of sun exposure and minimal intake of vitamin D from the diet, contributes to low breast milk vitamin D content and, therefore, infant vitamin D deficiency. The objective of this review was to examine the literature regarding evidence for achieving maternal vitamin D status that promotes sufficient vitamin D transfer from mother to infant exclusively from breast milk. PubMed and CINAHL databases were searched using the terms lactation or breastfeeding or milk, human and vitamin D. The resulting articles were further limited to those written in English, published within the last 10 years, and involving clinical or randomized controlled trials of humans. The search yielded 13 studies, 3 of which provide evidence for maternal intake of vitamin D and the correlation with exclusively breastfed infants' serum 25-hydroxyvitamin D level. A strong positive correlation exists between maternal vitamin D intake during exclusive breastfeeding and infant serum 25-hydroxyvitamin D levels. There is support to conclude that when maternal vitamin D intake is sufficient, vitamin D transfer via breast milk is adequate to meet infant needs. In the reviewed studies, doses up to 10 times the current recommended daily intake of vitamin D were needed to produce sufficient transfer from mother to breastfed infant. Further research is needed to refine the dose and gestational timing of maternal vitamin D supplementation. Due to the high rates of vitamin D deficiency during lactation and the correlations between vitamin D deficiency and multiple diseases, providers should consider monitoring lactating mothers' vitamin D status.

[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.

Prevalence and risk factors for vitamin D deficiency in children with iron deficiency anemia

PURPOSE

The increasing prevalence of breast feeding has led to concerns about vitamin D deficiency (VDD) and iron deficiency anemia (IDA) in children. We evaluated the prevalence of VDD in a population of Korean children with IDA and assessed the risk factors for VDD in these children.

METHODS

A total of 79 children who were diagnosed with IDA were prospectively surveyed from April 2010 to March 2011. Data were collected by questionnaire, medical assessment, and laboratory tests, including measurement of 25-hydroxyvitamin D (25OHD), hemoglobin, and wrist radiography.

RESULTS

The median age was 22 months and 30% of the subjects were female. Over a half of subjects (58%) had subnormal vitamin D level (25OHD<30 ng/mL), and VDD (25OHD<20 ng/mL) was present in 39% of children. There was no difference in serum hemoglobin level between IDA patients with VDD and those without VDD. Most subjects (89%) were currently or had recently been breastfed and almost all subjects (97%) who had VDD received breastfeeding. Children with VDD were more likely to be younger than 2 years, to have been breastfed, and to have been tested in winter or spring. Multivariable analysis indicated seasonal variation was a significant independent risk factor for VDD in our IDA patients.

CONCLUSION

Our results demonstrated that VDD has a high prevalence in Korean children with IDA. Primary care physicians should be aware of the possibility of VDD in children with IDA and should supplement the vitamin D as well as iron.

Heightened attention to supplementation is needed to improve the vitamin D status of breastfeeding mothers and infants when sunshine exposure is restricted

Although exclusively breastfed infants are at increased risk of vitamin D (vit D) deficiency if vit D supplementation is lacking and sun exposure is limited, assessment of both risk factors in the first year of life is lacking. We evaluated the contribution of vit D intake and sunlight exposure to vit D status in 120 healthy, breastfeeding mother-infant dyads, who were followed up for 1 year. Vitamin D intake and skin sunlight exposure were evaluated using questionnaires. Serum 25-hydroxyvitamin D, parathyroid hormone (PTH) and alkaline phosphatase levels were determined post-natally in mothers at 4 weeks and in infants at 4, 26 and 52 weeks. Vitamin D supplementation was low (<20%) and sunlight exposure was common (93%) in study infants. At 4 weeks, 17% of mothers were vit D deficient (<50 nmol L(-1)) and 49% were insufficient (50-<75 nmol L(-1)), while 18% of infants were severely vit D deficient (<25 nmol L(-1)) and 77% were deficient (<50 nmol L(-1)). At 26 weeks, winter/spring birth season and shorter duration of months of exclusive breastfeeding were protective of vit D deficiency in infants. Vitamin D deficiency in infants decreased to 12% at 52 weeks with sunlight exposure. Serum PTH levels were significantly higher in severely vit D deficient than sufficient infants. Vitamin D deficiency was widespread in early post-partum breastfeeding mothers and infants, and declined to one in eight infants at 52 weeks due mostly to sunshine exposure. When sunlight exposure is limited or restricted, intensified vit D supplementation of breastfeeding mothers and infants is needed to improve vit D status.

Vitamin D-fortified milk achieves the targeted serum 25-hydroxyvitamin D concentration without affecting that of parathyroid hormone in New Zealand toddlers

For young children, the level of vitamin D required to ensure that most achieve targeted serum 25-hydroxyvitamin D [25(OH)D] ≥50 nmol/L has not been studied. We aimed to investigate the effect of vitamin D-fortified milk on serum 25(OH)D and parathyroid hormone (PTH) concentrations and to examine the dose-response relationship between vitamin D intake from study milks and serum 25(OH)D concentrations in healthy toddlers aged 12-20 mo living in Dunedin, New Zealand (latitude 46°S). Data from a 20-wk, partially blinded, randomized trial that investigated the effect of providing red meat or fortified toddler milk on the iron, zinc, iodine, and vitamin D status in young New Zealand children (n = 181; mean age 17 mo) were used. Adherence to the intervention was assessed by 7-d weighed diaries at wk 2, 7, 11, 15, and 19. Serum 25(OH)D concentration was measured at baseline and wk 20. Mean vitamin D intake provided by fortified milk was 3.7 μg/d (range, 0-10.4 μg/d). After 20 wk, serum 25(OH)D concentrations but not PTH were significantly different in the milk groups. The prevalence of having a serum 25(OH)D <50 nmol/L remained relatively unchanged at 43% in the meat group, whereas it significantly decreased to between 11 and 15% in those consuming fortified study milk. In New Zealand, vitamin D intake in young children is minimal. Our findings indicate that habitual consumption of vitamin D-fortified milk providing a mean intake of nearly 4 μg/d was effective in achieving adequate year-round serum 25(OH)D for most children.

Clinical practice: diagnostic approach to the rachitic child

Rickets remains a common problem among infants and children in many countries worldwide. Although the classical presentation associated with bone abnormalities is well known, paediatricians need to be aware of atypical presentations, especially in the first 6 months of life. Furthermore, although vitamin D deficiency rickets remains the commonest form of rickets in most countries, health care providers need to be aware of other possible causes and their typical clinical and biochemical presentations. This article discusses these and highlights the characteristic features of various forms of rickets and possible pitfalls clinicians should be aware of when confronted with a patient with suspected rickets. In conclusion, the recent advances made in understanding the underlying pathogeneses of the various forms of rickets has helped to delineate the diagnostic tests that assist in the diagnosis and management of the disease in children.