Vitamin D deficiency in the 21st century: a persistent problem among Canadian infants and mothers

Vitamin D as an adjunct to antibiotics for the treatment of acute childhood pneumonia

BACKGROUND

Children with acute pneumonia may be vitamin D deficient. Clinical trials have found that prophylactic vitamin D supplementation decreases children's risk of developing pneumonia. Data on the therapeutic effects of vitamin D in acute childhood pneumonia are limited. This is an update of a Cochrane Review first published in 2018.

OBJECTIVES

To evaluate the efficacy and safety of vitamin D supplementation as an adjunct to antibiotics for the treatment of acute childhood pneumonia.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and two trial registries on 28 December 2021. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared vitamin D supplementation with placebo in children (aged one month to five years) hospitalised with acute community-acquired pneumonia, as defined by the World Health Organization (WHO) acute respiratory infection guidelines. For this update, we reappraised eligible trials according to research integrity criteria, excluding RCTs published from April 2018 that were not prospectively registered in a trials registry according to WHO or Clinical Trials Registry - India (CTRI) guidelines (it was not mandatory to register clinical trials in India before April 2018).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and extracted data. For dichotomous data, we extracted the number of participants experiencing the outcome and the total number of participants in each treatment group. For continuous data, we used the arithmetic mean and standard deviation (SD) for each treatment group together with number of participants in each group. We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

In this update, we included three new trials involving 468 children, bringing the total number of trials to seven, with 1601 children (631 with pneumonia and 970 with severe or very severe pneumonia). We categorised three previously included studies and three new studies as 'awaiting classification' based on the research integrity screen. Five trials used a single bolus dose of vitamin D (300,000 IU in one trial and 100,000 IU in four trials) at the onset of illness or within 24 hours of hospital admission; one used a daily dose of oral vitamin D (1000 IU for children aged up to one year and 2000 IU for children aged over one year) for five days; and one used variable doses (on day 1, 20,000 IU in children younger than six months, 50,000 IU in children aged six to 12 months, and 100,000 IU in children aged 13 to 59 months; followed by 10,000 IU/day for four days or until discharge). Three trials performed microbiological diagnosis of pneumonia, radiological diagnosis of pneumonia, or both. Vitamin D probably has little or no effect on the time to resolution of acute illness (mean difference (MD) -1.28 hours, 95% confidence interval (CI) -5.47 to 2.91; 5 trials, 1188 children; moderate-certainty evidence). We do not know if vitamin D has an effect on the duration of hospitalisation (MD 4.96 hours, 95% CI -8.28 to 18.21; 5 trials, 1023 children; very low-certainty evidence). We do not know if vitamin D has an effect on mortality rate (risk ratio (RR) 0.69, 95% CI 0.44 to 1.07; 3 trials, 584 children; low-certainty evidence). The trials reported no major adverse events. According to GRADE criteria, the evidence was of very low-to-moderate certainty for all outcomes, owing to serious trial limitations, inconsistency, indirectness, and imprecision. Three trials received funding: one from the New Zealand Aid Corporation, one from an institutional grant, and one from multigovernment organisations (Bangladesh, Sweden, and UK). The remaining four trials were unfunded.

AUTHORS' CONCLUSIONS

Based on the available evidence, we are uncertain whether vitamin D supplementation has important effects on outcomes of acute pneumonia when used as an adjunct to antibiotics. The trials reported no major adverse events. Uncertainty in the evidence is due to imprecision, risk of bias, inconsistency, and indirectness.

Maternal excess adiposity and serum 25-hydroxyvitamin D < 50 nmol/L are associated with elevated whole body fat mass in healthy breastfed neonates

BACKGROUND

Vitamin D status of pregnant women is associated with body composition of the offspring. The objective of this study was to assess whether the association between maternal vitamin D status and neonatal adiposity is modified by maternal adiposity preconception.

METHODS

Healthy mothers and their term appropriate weight for gestational age (AGA) infants (n = 142; 59% male, Greater Montreal, March 2016-2019) were studied at birth and 1 month postpartum (2-6 weeks). Newborn (24-36 h) serum was collected to measure total 25-hydroxyvitamin D [25(OH)D] (immunoassay); maternal pre-pregnancy BMI was obtained from the medical record. Anthropometry, body composition (dual-energy X-ray absorptiometry) and serum 25(OH)D were measured at 2-6 weeks postpartum in mothers and infants. Mothers were grouped into 4 categories based on their vitamin D status (sufficient 25(OH)D ≥ 50 nmol/L vs. at risk of being insufficient < 50 nmol/L) and pre-pregnancy BMI (< 25 vs. ≥25 kg/m2): insufficient-recommended weight (I-RW, n = 24); insufficient-overweight/obese (I-OW/O, n = 21); sufficient-recommended weight (S-RW, n = 69); and sufficient-overweight/obese (S-OW/O, n = 28). Partial correlation and linear fixed effects model were used while adjusting for covariates.

RESULTS

At birth, infant serum 25(OH)D mean concentrations were below 50 nmol/L, the cut-point for sufficiency, for both maternal pre-pregnancy BMI categories; 47.8 [95%CI: 43.8, 51.9] nmol/L if BMI < 25 kg/m2 and 38.1 [95%CI: 33.5, 42.7] nmol/L if BMI ≥25 kg/m2. Infant serum 25(OH)D concentrations at birth (r = 0.77; P < 0.0001) and 1 month (r = 0.59, P < 0.0001) were positively correlated with maternal postpartum serum 25(OH)D concentrations. Maternal serum 25(OH)D concentration was weakly correlated with maternal percent whole body fat mass (r = - 0.26, P = 0.002). Infants of mothers in I-OW/O had higher fat mass versus those of mothers in S-OW/O (914.0 [95%CI: 766.4, 1061.6] vs. 780.7 [95%CI: 659.3, 902.0] g; effect size [Hedges' g: 0.42]; P = 0.04 adjusting for covariates) with magnitude of difference of 220.4 g or ~ 28% difference.

CONCLUSIONS

Maternal and neonatal vitamin D status are positively correlated. In this study, maternal adiposity and serum 25(OH)D < 50 nmol/L are dual exposures for neonatal adiposity. These findings reinforce the importance of vitamin D supplementation early in infancy irrespective of vitamin D stores acquired in utero and maternal weight status.

Vitamin D as an adjunct to antibiotics for the treatment of acute childhood pneumonia

BACKGROUND

Children with acute pneumonia may be vitamin D deficient. Clinical trials have found that prophylactic vitamin D supplementation decreases the risk of developing pneumonia in children. Data on the therapeutic effects of vitamin D in acute childhood pneumonia are limited.

OBJECTIVES

To evaluate the efficacy and safety of vitamin D supplementation as an adjunct to antibiotics for the treatment of acute childhood pneumonia.

SEARCH METHODS

We searched CENTRAL (2017, Issue 7), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register; Ovid MEDLINE Epub Ahead of Print; In-Process & Other Non-Indexed Citations; Ovid MEDLINE Daily and Ovid MEDLINE (1946 to July Week 4, 2017); and Embase (2010 to 28 July 2017). We also searched ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) on 28 July 2017. There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) including children (aged over one month and up to five years) hospitalised with acute community-acquired pneumonia, as defined by the WHO acute respiratory infection guidelines, that compared vitamin D supplementation with control.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and extracted data. For dichotomous data, we extracted the number of participants experiencing the outcome and the total number of participants in each treatment group. For continuous data, we used the arithmetic mean and standard deviation (SD) for each treatment group together with numbers of participants in each group. We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included seven RCTs conducted in low-income countries that involved 1529 children (780 with pneumonia and 749 with severe or very severe pneumonia). Four studies used a single 100,000 IU dose of vitamin D₃ at the onset of illness or within 24 hours of hospital admission; two used a daily dose of oral vitamin D₃ (1000 IU for children aged up to one year and 2000 IU for children aged over one year) for five days; and one used a daily dose of oral vitamin D₃ (50,000 IU) for two days. One study reported microbiological and radiological diagnosis of pneumonia.The effects of vitamin D on outcomes were inconclusive when compared with control: time to resolution of acute illness (hours) (mean difference (MD) -0.95, 95% confidence interval (CI) -6.14 to 4.24; 3 studies; 935 children; low-quality evidence) mortality rate (risk ratio (RR) 0.97, 95% CI 0.06 to 15.28; 1 study; 193 children; very low-quality evidence); duration of hospitalisation (MD 0.49, 95% CI -8.41 to 9.4; 4 studies; 835 children; very low-quality evidence) and time to resolution of fever (MD 1.66, 95% CI -2.44 to 5.76; 4 studies; 584 children; very low-quality evidence).No major adverse events were reported.The GRADE assessment found very low-quality evidence (due to serious study limitations, inconsistencies, indirectness, and imprecision) for all outcomes except time to resolution of acute illness.One study was funded by the New Zealand Aid Corporation; one study was funded by an institutional grant; and five studies were unfunded.

AUTHORS' CONCLUSIONS

We are uncertain as to whether vitamin D has an important effect on outcomes because the results were imprecise. No major adverse events were reported. We assessed the quality of the evidence as very low to low. Several trials are ongoing and may provide additional information.

Relationship between newborn craniotabes and vitamin D status

OBJECTIVE

In recent studies, vitamin D deficiency during pregnancy and early infancy has been reported to predispose children to many chronic diseases, except those of the skeletal system. The aim of this study was to investigate whether craniotabes in otherwise healthy newborns is physiological, its relationship to vitamin D deficiency and whether or not it requires treatment.

METHODS

A total of 150 healthy newborns with a weight of over 2000 g were included. Newborns were divided into two groups during postnatal discharge (1-3.'s day): those with and without craniotabes. The 25-hydroxy (OH) vitamin D levels of the newborns' mothers were measured, and all infants were re-evaluated for craniotabes, as well as tested to determine levels of serum calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH) and 25(OH) vitamin D, urine calcium and creatinine.

RESULTS

Craniotabes was present in 45 (30%) of newborns enrolled in the study. Craniotabes of the newborns born during the winter months was significantly higher. PTH level was significantly higher in 1-month-old newborns with craniotabes than those without craniotabes. No relationship was observed between diet and craniotabes, but in exclusively breastfed infants, vitamin D level was statistically significantly lower. No statistically significant difference was found in the occurrence of craniotabes in newborns with or without vitamin D support.

CONCLUSION

The relationship between newborn craniotabes and maternal vitamin D deficiency is not clear. However, the present study illustrates that maternal vitamin D deficiency is still a major problem. Therefore, measures to prevent maternal vitamin D deficiency should be strengthened.

Vitamin D Deficiency in Pregnant Women and Their Neonates

BACKGROUND & OBJECTIVE

Vitamin D deficiency during pregnancy is a worldwide problem. Studies have reported prevalence ranged 18-84% in pregnant women. Receiving adequate calcium and vitamin D during pregnancy period is necessary for calcium homeostasis, fetal growth and bone mineralization. This study was aimed to determine the prevalence of vitamin D deficiency in pregnant women and their neonates in Shahroud city in the northeast Iran.

METHODS

In this cross-sectional study, 284 pregnant women and their neonates referred to Fatemiyeh Hospital of Shahroud were included. Blood samples of mothers and umbilical cords were collected during the delivery and were sent to laboratory in order to measure calcium and 25-hydroxy vitamin D.

FINDINGS

Amounts of Vitamin D insufficiency (20-30 ng/mL) and deficiency (<20 ng/mL) in (mothers, neonates) were found to be (60.2%, 48.9%) and (1.1%, 2.5%) respectively. Calcium deficiency (<8.5 mg/dL) was present in 33.5% of mothers and 25% of neonates. There was a weak correlation between maternal serum and cord blood 25-hydroxy vitamin D (r=0.12, p=0.053).

CONCLUSION

More than half of the mothers and their neonates had some degrees of vitamin D deficiency. It is recommended to evaluate the nutritional status of vitamin D in pregnant women along with public health interventions to be carried out.

[Vitamin D deficiency in childhood: an opportunity for prevention]

The prevalence of vitamin D deficiency in the pediatric population has increased in recent years and continues to be underdiagnosed and undertreated. According to data from the "ENSANUT 2006" (National Health and Nutrition Survey), the prevalence of vitamin D deficiency in Mexico was 16% in children aged 2-12 years. Vitamin D plays a critical role in the formation and bone homeostasis and consequently on growth. Its deficiency is clearly associated with diseases such as rickets and osteomalacia, and it has been linked to other diseases such as obesity, metabolic syndrome, diabetes, cancer, respiratory infections and immune system disease. Specific risk groups have been described in the medical literature for vitamin D deficiency in which supplementation may offer a benefit. Currently, there is still controversy in defining the serum levels of proficiency and dose supplementation. In Mexico, the daily suggested intake of vitamin D is 5.6μg (224 IU), which is significantly lower than the recommendations in the U.S. and Europe (i.e., between 400 and 1000 IU/day). An increase in vitamin D deficiency has been reported in recent years. There is no consensus regarding the sufficiency levels of vitamin D. Cut-off values vary from 20 to 30ng/ml. Therefore, the objective of this review was to provide an overview of the problem in the pediatric population and to describe the groups at risk, as well as to analyze the current recommendations for vitamin D supplementation. Vitamin D deficiency was considered rare in Mexico according to the National Institute of Medical Science and Nutrition Salvador Zubirán. Lack of evidence did not help to establish the international recommended daily intake. Currently, vitamin D deficiency must be recognized as a health problem, worthy of attention and action. We suggest that prospective studies are carried out in our country where the relationship between serum vitamin D deficiency and poor bone mineralization will be established.

25-Hydroxyvitamin D Can Interfere With a Common Assay for 1,25-Dihydroxyvitamin D in Vitamin D Intoxication

CONTEXT

Vitamin D intoxication is characterized by elevated serum 25-hydroxyvitamin D (25(OH)D) and suppressed serum 1,25-dihydroxvitamin D (1,25(OH)2D). We evaluated two adolescents with hypercalcemia due to vitamin D intoxication; both had elevated serum 1,25(OH)2D by Diasorin RIA, but normal serum 1,25(OH)2D concentrations by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

OBJECTIVE

This study aimed to determine the effect of 25(OH)D2 and 25(OH)D3 on 1,25(OH)2D concentration determined using RIA and LC-MS/MS.

METHODS

Pools of normal serum and an artificial serum matrix were prepared and aliquots were spiked with >99% pure 25(OH)D2 or 25(OH)D3 (50-700 ng/mL). Samples were maintained at 4°C or heated to 56°C, and the concentrations of vitamin D metabolites were measured by LC-MS/MS and Diasorin RIA.

RESULTS

Median 1,25(OH)2D increased by 114% with RIA and 21% with LC-MS/MS with addition of 100 ng/mL 25(OH)D3, and 349% (RIA) and 117% (LC-MS/MS) with 700 ng/mL of 25(OH)D3. Each 1-ng/mL increase in 25(OH)D3 increased 1,25(OH)2D by 0.231 pg/mL (RIA) and 0.121 pg/mL (LC-MS/MS). Spiking with 25(OH)D2 led to similar changes. Heat inactivation of serum, and using an artificial serum matrix, were associated with similar effects of 25(OH)D on 1,25(OH)2D assays.

CONCLUSIONS

Vitamin D intoxication with high serum levels of 25(OH)D2 or 25(OH)D3 can be associated with elevated levels of 1,25(OH)2D due to interference in a commonly used RIA. A similar but attenuated effect also occurs when 1,25(OH)2D is measured using LC-MS/MS but does not seem to be clinically significant. The basis for this effect on the LC-MS/MS assay is presently uncertain.

Comparison of infant vitamin D supplement use among Canadian-born, immigrant, and refugee mothers

PURPOSE

This study compares knowledge and practice of infant vitamin D supplementation among immigrant, refugee, and Canadian-born mothers.

METHOD

Focus group discussions with 94 mothers of children aged 0 to 3 years recruited from early childhood centers and a refugee health clinic.

FINDINGS

Both immigrant and Canadian-born mothers indicated good knowledge and use of infant vitamin D supplementation. In contrast, Canadian government-assisted refugees were less likely to supplement with vitamin D. The main source of information about vitamin D was public health prenatal classes. Many mothers reported inconsistent guidance from health care providers.

DISCUSSION AND CONCLUSIONS

Exclusively breastfed infants of refugees may be more at risk of vitamin D deficiency. All mothers require clear recommendations, both in clinical and public health settings.

IMPLICATIONS FOR PRACTICE

Mothers, both new Canadian and Canadian-born, require clear and consistent messaging from health professionals. Refugee mothers, however, require more educational support to promote infant vitamin D supplementation.

Obstructive sleep apnea syndrome and its association with vitamin D deficiency

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is a widespread disorder characterized by recurrent, partial or complete episodes of apnea due to upper airway tract obstruction during sleeping period. Deficiency of vitamin D has roles in development of many diseases. Association between presence and severity of OSAS and vitamin D has recently gained research interest.

AIM

The aim of our study was to investigate the association between serum 25-hydroxy [25 (OH)] vitamin D levels and severity of disease in patients with OSAS.

MATERIAL AND METHODS

One hundred and fifty OSAS patients (50 patients with mild, 50 with moderate, 50 with severe OSAS) who were diagnosed by polysomnography (PSG) and 32 non-OSAS controls who were referred to the Health Ministry Ankara Numune Training and Research Hospital, Endocrinology and Metabolism Department, from January 2010 to May 2011 were included in the study. Serum 25(OH)D, PTH, calcium and phosphorus levels were evaluated in all the patients who were recruited to the study.

RESULTS

There was no statistically significant difference in serum 25(OH)D levels between OSAS and controls (p>0.05). However, in subgroup analysis of OSAS, we found that the patients with severe OSAS had significantly lower levels of 25(OH)D as compared with other groups (p=0.003). Also, the number of patients with serum 25(OH)D deficiency (<10 μg/dl) were higher in OSAS group than in controls (p<0.05).

CONCLUSIONS

We found that when the severity of OSAS increases, 25(OH)D deficiency becomes more pronounced.

Comparison between daily supplementation doses of 200 versus 400 IU of vitamin D in infants

The daily supplementation of vitamin D is mandatory for infants. However, there are still conflicting opinions about the exact daily dose. Thus, we aimed to evaluate a daily supplementation dose of 200 IU is sufficient and compared the supplementation doses of 200 and 400 IU per day. One hundred and sixty-nine infants were randomly assigned to two groups (group 1, 200 IU/day; group 2, 400 IU/day) and there were 75 infants in group 1 and 64 were in group 2 with a total number of 139. The median levels of 25-hydroxyvitamin D3 were significantly increased in group 2 at the age of 4 months (group 1, 39.60 mcg/L; group 2, 56.55 mcg/L; p < 0.0001). We clearly demonstrated that at the age of 4 months, none of the infants on the group 2 had a serum level of 25-hydroxyvitamin D3 less than 30 mcg/L. However, 21.3% of the infants in group 1 had a level below 30 mcg/L. Thus, in order to avoid vitamin D deficiency and rickets, we recommend supplementation dose of vitamin D at 400 IU/day as a safe and effective dose.

Vitamin D status of exclusively breastfed 4-month-old infants supplemented during different seasons

OBJECTIVE

To examine the vitamin D status of 4-month-old exclusively breastfed infants supplemented with 400 IU daily of vitamin D and to determine whether there was any seasonal variation in serum 25-hydroxyvitamin D (25(OH)D) levels of infants.

METHODS

In this cross-sectional study, serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone, and 25(OH)D levels of 143 exclusively breastfed 4-month-old infants supplemented daily with 400 IU of vitamin D were measured in a temperate latitude, Izmir, Turkey, between May 2008 and April 2009. A questionnaire on demographic characteristics of infants and mothers, vitamin D supplementation of infants after birth, mothers' multivitamin supplementation, dressing habits, and consumption of dairy products during pregnancy was used.

RESULTS

Vitamin D deficiency (≤ 50 nmol/L) and insufficiency (51-74 nmol/L) were determined in 40 (28%) and 55 (38.5%) infants, respectively. During winter days, serum 25(OH)D levels were <20 ng/mL in 45.4% of infants and <10 ng/mL in 10.6% of infants. Season of blood sampling, compliance of vitamin D supplementation, maternal education level, and consumption of dairy products were highly predictive of serum 25(OH)D levels in multiple linear regression analysis (P < .05). The use of the Pearson correlation test found a statistically significant negative correlation between 25(OH)D and parathyroid hormone levels (r = -0.419, P < .001).

CONCLUSIONS

Despite supplementation with 400 IU of vitamin D daily, the rate of vitamin D deficiency was worryingly high in 4-month-old exclusively breastfed infants living in Izmir, Turkey. So, additional studies are needed to clarify optimal amount of vitamin D supplementation to the infants, especially during winter days.

Nutritional strategy for adolescents undergoing bariatric surgery: report of a working group of the Nutrition Committee of NASPGHAN/NACHRI

Surgical options for the treatment of adolescent obesity have been gaining popularity. Adolescent patients present a particular challenge to clinicians, secondary to age-related issues, revolving around both mental and physical growth. These age-related issues require a unique approach to nutritional intervention for adolescents undergoing bariatric surgery as opposed to standardized approaches for adults. Despite the increasing numbers of adolescents undergoing obesity surgery, evidence-based nutritional guidelines have yet to be published. The goal of this document is to provide the clinician with recommendations on how to assess, educate, nourish, and monitor the adolescent who has undergone obesity surgery. A multidisciplinary panel composed of 3 pediatric gastroenterologists, 1 psychologist, and 3 registered dietitians from the Nutrition Committee for the North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition and National Association of Children's Hospitals and Related Institutions, with experience in nutrition and adolescent weight loss surgery, reviewed the medical literature for evidence-based practice for nutritional strategies for patients undergoing bariatric surgery. In addition to this group, an adolescent medicine physician was consulted for matters related to reproductive health. The present article presents a consensus of recommendations based on a review of the literature. In areas for which there was a lack of evidence to support the recommendations, best-practice guidelines were used. The present article provides the clinician with an overview of the nutritional concerns for adolescent patients undergoing obesity surgery. These guidelines address the preoperative educational pathway, the postoperative diet progression, recognition of disordered eating, guidelines for female reproductive issues, and assistance for the adolescent in a school/college environment.

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.

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.

Nutritional deficiencies during normal growth

Nutritional deficiencies have always been a major consideration in pediatrics. Although the classic forms of many of the well-documented nutritional deficiencies are memorized during training as a physician, nutritional deficiencies that can occur in otherwise asymptomatic normally growing children are often overlooked. The two most common deficiencies seen in children who are growing normally are iron and vitamin D deficiencies. These deficiencies are surprisingly common and can have a significant impact on the overall health of a child. This article reviews these nutritional deficiencies and other less commonly seen deficiencies in children who are otherwise growing normally.

Does vitamin D make the world go 'round'?

Abstract Vitamin D has emerged from obscurity, and its effects on various organ systems throughout the body down to the cellular level are being discovered. What was once thought to be a simple hormone affecting only bone and calcium metabolism has shifted. We no longer see vitamin D as a "vitamin" important only in childhood, but as a complex hormone that is involved not only in calcium homeostasis but also in the integrity of the innate immune system. Vitamin D deficiency is linked to inflammatory and long-latency diseases such as multiple sclerosis, rheumatoid arthritis, tuberculosis, diabetes, and various cancers, to name a few. In this review, we trace how we came to view vitamin D and how that view led to one of the largest epidemics of nutrient deficiency beginning in the late 20(th) century. We then discuss the needs of vitamin D in the context of the breastfeeding mother and her infant and child, why breastfed infants are particularly at risk, and what to do about it.

Prevention of rickets and vitamin D deficiency in infants, children, and adolescents

Rickets in infants attributable to inadequate vitamin D intake and decreased exposure to sunlight continues to be reported in the United States. There are also concerns for vitamin D deficiency in older children and adolescents. Because there are limited natural dietary sources of vitamin D and adequate sunshine exposure for the cutaneous synthesis of vitamin D is not easily determined for a given individual and may increase the risk of skin cancer, the recommendations to ensure adequate vitamin D status have been revised to include all infants, including those who are exclusively breastfed and older children and adolescents. It is now recommended that all infants and children, including adolescents, have a minimum daily intake of 400 IU of vitamin D beginning soon after birth. The current recommendation replaces the previous recommendation of a minimum daily intake of 200 IU/day of vitamin D supplementation beginning in the first 2 months after birth and continuing through adolescence. These revised guidelines for vitamin D intake for healthy infants, children, and adolescents are based on evidence from new clinical trials and the historical precedence of safely giving 400 IU of vitamin D per day in the pediatric and adolescent population. New evidence supports a potential role for vitamin D in maintaining innate immunity and preventing diseases such as diabetes and cancer. The new data may eventually refine what constitutes vitamin D sufficiency or deficiency.

Season of birth and prevalence of overweight and obesity in Canada

BACKGROUND

The contexts of prenatal life, such as one's season of birth, have been shown to influence health later in life. For example, research has shown a disproportionate number of schizophrenic patients are born during the late winter and early spring. The purpose of this study was to examine season of birth as a possible risk for overweight and obesity.

METHODOLOGY

Utilizing cycle 2.1 of the Canadian Community Health Survey, birth data of respondents 12 to 64 years old were examined. The risk associated with season of birth was compared to risks previously identified for overweight and obesity (e.g. physical inactivity, low socioeconomic status etc.).

RESULTS

Overall, among the 20-64 year olds, those in the obese III (BMI> or =40 kg/m(2)) category were 1.54 times more likely to be born in the winter (95% CI: 1.21-1.95). This effect appears largely due to a winter/spring season of birth effect among the obese II/III (BMI> or =35) 20-29 y cohort (Winter OR: 1.53, 95% CI: 1.08-2.18; Spring OR: 1.55, 95% CI: 1.10-2.18). A summer season of birth effect was observed for the obese II/III 40-49 y cohort (OR: 1.59, 95% CI: 1.21-2.11). No season of birth effects were observed among any BMI categories for those 12-19 years, or among those 20 y and over in the overweight BMI category.

CONCLUSION

A greater proprtion of class III obese Canadians are born during the winter/spring, particularly in the 20-29 y age cohort. However, other factors (e.g. physical inactivity) represent greater risks for obesity than season of birth.

Vitamin D deficiency in children and its management: review of current knowledge and recommendations

Given the recent spate of reports of vitamin D deficiency, there is a need to reexamine our understanding of natural and other sources of vitamin D, as well as mechanisms whereby vitamin D synthesis and intake can be optimized. This state-of-the-art report from the Drug and Therapeutics Committee of the Lawson Wilkins Pediatric Endocrine Society was aimed to perform this task and also reviews recommendations for sun exposure and vitamin D intake and possible caveats associated with these recommendations.

Neonatal vitamin D status at birth at latitude 32 degrees 72': evidence of deficiency

OBJECTIVE

With vitamin D deficiency as a serious public health problem, vitamin D status at birth was measured in neonates at latitude 32 degrees 72' (southeastern United States).

STUDY DESIGN

In umbilical cord blood, vitamin D status, demonstrated by circulating 25-hydroxyvitamin D, was measured and related to race and season of birth.

RESULT

The mean+/-standard deviation of 25-hydroxyvitamin D in 100 cord blood samples was 13.5+/-8.3 ng/ml for the cohort. African-American infants, with a mean+/-standard deviation of 10.5+/-6.0 ng/ml, demonstrated significantly lower vitamin D status than Caucasian infants, with a mean+/-standard deviation of 19.5+/-9.6 ng/ml (P<0.0001). By season, the mean 25-hydroxyvitamin D level at birth in November-March compared to April-October was 11.3 ng/ml lower in Caucasian infants (from 29.0 to 17.7 ng/ml) and 3 ng/ml lower in African-American infants (from 13.1 to 10.1 ng/ml).

CONCLUSION

The prevalence of vitamin D insufficiency is high in this cohort. African-American infants demonstrate significantly lower vitamin D status at birth than Caucasian infants. Seasonality, while significant in both groups, had a greater impact on the vitamin D status of Caucasian newborns.

Lactating Women Restricting Milk Are Low on Select Nutrients

OBJECTIVE

Currently there are no recommendations for vitamin/mineral supplementation for lactating women but supplementation may be important, particularly for those women who choose to restrict milk intake during lactation. The objective of this study was to assess nutrient adequacy for lactating women and compare their dietary intake, including supplements, between those who restrict milk and those who do not.

METHODS

A cohort of 175 healthy exclusively breast-feeding women (19-45 yrs) recruited from prenatal classes were divided into milk restrictors (RS) defined as milk intake < or = 250 ml/day and non-restrictors (NRS) (>250 ml/day) and followed for six months postpartum. Participants provided repeated 24-hr dietary recalls, detailed use of vitamin/mineral supplements and reasons for restricting milk.

STATISTICAL ANALYSES

Observed intakes were adjusted to remove day-to-day variability. Nutrient intakes were estimated for macronutrients and vitamins C, D, thiamin, riboflavin, niacin, and minerals, calcium and zinc, with and without vitamin/mineral supplements. Chi-square was used to compare the number of RS and NRS with intakes less than the Estimated Average Requirement (EAR).

RESULTS

Milk restriction was practiced by 23% of the sample. Sixty per cent of RS reported protein intakes <EAR compared to 38% of NRS (chi(2) = 6.22, p < 0.05). Prior to supplementation, mean levels of calcium and vitamin D intakes for RS were below the adequate intake level (AI) and lower than NRS estimated intakes (p < 0.05). Following supplementation, mean levels of these nutrients reached AI for both groups. RS remained lower than NRS. RS had lower energy intakes than NRS (p < 0.05) but no difference in weight loss at 6 months was noted. A higher proportion of RS were below the EAR for thiamin, riboflavin and zinc.

CONCLUSIONS

Milk restriction compromised protein and nutrient intakes in lactating women who restricted milk to <250 mL. Vitamin/mineral supplements helped exclusively breastfeeding milk restrictors improve their vitamin D and calcium intakes. Milk restriction is not recommended during lactation and where unavoidable, nutrients provided by milk should be compensated for by other foods or supplements.

Low vitamin D status in mother-newborn pairs in Greece

Adequate vitamin D status during pregnancy is crucial to assure normal fetal skeletal growth and to provide the vitamin D needed for infants' stores. To determine the actual situation in Greece, we evaluated serum 25-hydroxyvitamin D (25[OH]D), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), osteocalcin (OC), and calcitonin (CT) concentrations in 123 healthy mother-newborn pairs recruited from a public hospital of the sunny Athenian region. Blood samples were obtained from pregnant women at term and their neonates (cord blood). The study was conducted between June 2003 and May 2004. None of the mothers has been prescribed vitamin D supplements. Maternal 25(OH)D levels (16.4 [11-21.1] ng/mL) were significantly lower than umbilical venous blood concentrations (20.4 [13.9-30.4] ng/mL) (P < 0.001). A strong correlation was observed between maternal and infant 25(OH)D concentrations (r = 0.626, P < 0.001). Twenty-four (19.5%) mothers and 10 (8.1%) neonates had 25(OH)D <10 ng/mL. Pregnant women who delivered in summer and autumn reported higher levels of 25(OH)D (18.9 [12.9-23.3] ng/mL) than those who delivered in winter and spring (14.6 [10.1-18.5] ng/mL) (P = 0.006). Mothers with a darker phototype had lower levels of serum 25(OH) D than those with a fair phototype (P = 0.023). Umbilical venous blood Ca, P, OC, and CT levels were significantly higher than maternal venous blood levels (P < 0.001). PTH umbilical levels were lower than maternal levels (P < 0.001). Apparently, the abundant sunlight exposure in Athens is not sufficient to prevent hypovitaminosis D. Pregnant women should be prescribed vitamin D supplementations, and the scientific community should consider vitamin D supplementation of foods.

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.