Calcium and vitamin D metabolism in children in developing countries

Association Between Vitamin D Insufficiency and Impaired Bone Density Among Adolescents With Perinatally Acquired HIV Infection

Background

Stunting and pubertal delay are common among children growing up with human immunodeficiency virus (HIV) and are associated with bone and muscle impairments. We investigated factors associated with bone density and muscle function in adolescents living with HIV (ALWH).

Methods

The VITALITY trial (PACTR202009897660297) investigated whether vitamin D and calcium supplementation improves musculoskeletal health among ALWH. A total of 842 ALWH aged 11-19 years, established on antiretroviral therapy (ART) for ≥6 months, were enrolled from HIV clinics in Zambia and Zimbabwe. Clinical history and examination were undertaken, and serum 25-hydroxyvitamin D3 (25[OH]D3) was measured. Dual-energy X-ray absorptiometry measured total-body-less-head bone mineral density adjusted for height (TBLH-BMDHT), and lumbar spine bone mineral apparent density (LS-BMAD) z scores. The association between a priori-defined covariates and musculoskeletal outcomes were investigated using baseline enrollment data and multivariable logistic regression.

Results

TBLH-BMDHT  z scores were impaired (mean, -1.42 for male and -0.63 female participants), as were LS-BMAD z scores (mean -1.15 for male and -0.47 for female participants). In bivariate analysis, early pubertal stage, less physical activity, and older age at ART initiation were associated with lower TBLH-BMDHT  z scores. Younger age, early pubertal stage, and low socioeconomic status were associated with lower LS-BMAD z scores. Grip-strength-for-height and jump-power-for-height z scores were associated with lower TBLH-BMDHT and LS-BMAD z scores. Low dietary vitamin D and calcium were associated with lower adjusted TBLH-BMDHT  z scores. Lower 25(OH)D3 was associated with lower adjusted TBLH-BMDHT and LS-BMAD z scores.

Conclusions

Deficits in bone density are common in ALWH. Vitamin D and calcium supplementation and promotion of exercise may improve musculoskeletal health among perinatally infected ALWH.

Inositol Hexaphosphate in Bone Health and Disease

Dietary phytic acid/phytate/myo-inositol hexaphosphate (IP6), a phosphate reservoir in plants, was viewed as antinutrient, caused by an influence on the bioavailability of minerals through its chelating activity. However, there is a growing body of evidence indicating that IP6 has beneficial (e.g., antiinflammatory, antibacterial, and anticancer) effects on multiple biological processes. Also, IP6 and its metabolites are known to exist in mammalian cells, including human cells, and the role of IP6 as a functional molecule is attracting attention. IP6 can bind to the growth sites of hydroxy-apatite (HA) and calcium oxalate crystals to prevent their growth and hence inhibit pathological calcification. SNF472, hexasodium IP6, is currently being evaluated in clinical studies as a treatment for vascular calcification and calciphylaxis. However, since HA crystal growth within bone matrix is an essential process in bone formation, it is possible that IP6 intake may inhibit physiological mineralization and bone formation, although currently more published studies suggest that IP6 may contribute to bone health rather than inhibit bone formation. Given that IP6 and its metabolites are thought to have diverse activities and many health benefits, it remains important to consider the range of effects of IP6 on bone.

Global prevalence of diet low in calcium and the disease burden: results from the Global Burden of Disease Study 2019

BACKGROUND

Due to the essential role of calcium in vital biological functions, diet low in calcium (DLC) is associated with various diseases. However, there is a lack of study about the current prevalence and health burden due to DLC using reliable data sources.

METHODS

We used data from the Global Burden of Disease study 2019 (GBD 2019) to estimate the prevalence and health burden of DLC in 204 countries from 1990 to 2019, by age, sex, and sociodemographic index (SDI). The estimates were produced in DisMod-MR 2.1, a Bayesian meta-regression tool. Summary exposure value (SEV) was used to show the prevalence of DLC, while diseases adjusted life year (DALY) was used to represent the disease burden. The disease burden was estimated for DLC-induced colorectal cancer. Spearman Rank Order correlation was used for correlation analysis, and estimated annual percentage (EAPC) was used to reflect the temporal trends.

RESULTS

From 1990 to 2019, the global prevalence of DLC decreased (EAPC of SEV, -0.47; 95% CI, -0.5 to -0.43), but have increased in Oceania region and in many countries, such as United Arab Emirates, New Zealand, Japan, and France. The global DALYs associated with low in calcium were estimated to be 3.14 million (95% uncertainty interval (UI), 2.25-4.26 million) in 2019, with an age standardized rate of 38.2 (95% UI, 27.2-51.8) per 100,000. Unlike the prevalence, the global age standardized DALY rates has remained unchanged (EAPC, -0.03; 95% CI, -0.12 to 0.07), but has increased in over 80 of the 204 countries, located mainly in Asia, Africa, and South America. In all years and regions, the age standardized SEV and DALY rates were higher in male people than that in female people. The prevalence (rho = -0.823; P < 0.001) and disease burden (rho = -0.433; P < 0.001) associated with diet in low calcium were strongly correlated to SDI. The prevalence decreased with age, but the DALY rates increased with age and peaked at about 90 years. The prevalence of DLC has decreased worldwide and in most countries, but the disease burden of DLC induced colorectal cancer has increased in over 40% of countries worldwide.

CONCLUSION

Countries with low sociodemographic level and male people are more likely to experience the risk of DLC and related disease burden. Related measures in improve dietary calcium intake are in need to address diet in low calcium related health problems.

Prevalence and Risk Factors of Vitamin D, Calcium and Phosphate Deficiency among Apparently Healthy Children Aged 6-24 Months in a Semi-urban Community in Southwest, Nigeria

BACKGROUND

Adequate levels of calcium, phosphate and Vitamin D are essential for bone physiology and growth, as well as preventing some common childhood illnesses. This study aimed to determine the prevalence of the deficiencies of these nutrients and factors affecting their serum levels in Nigerian children.

METHODS

This was a cross-sectional study that involved 220 apparently healthy children aged 6-24 months in Ikenne Local Government Area of Ogun State, Nigeria. Serum calcium and phosphate were assayed using the calorimetric method, while Vitamin D (25-OH Vitamin D) was assayed with ELISA.

RESULTS

The mean (±standard deviation [SD]) serum Vitamin D level was 55.07 ± 16.53 ng/ml, while the mean (±SD) serum calcium and phosphate were 2.27 ± 0.13 mmol/l and 1.28 ± 0.18 mmol/l, respectively. Eleven (5%) of the children had hypovitaminosis D, 23 (10.5%) had hypocalcaemia and 12 (5.5%) had hypophosphataemia. Factors found to be significantly associated with hypovitaminosis D included low consumption of milk and the use of a hijab veil, while malnutrition (both undernutrition and overnutrition) was significantly associated with hypocalcaemia.

CONCLUSION

The prevalence levels of hypovitaminosis D and hypophosphataemia were low, while hypocalcaemia was more common. Low milk consumption and use of a hijab veil were risk factors for hypovitaminosis D, while malnutrition was a risk factor for hypocalcaemia. Malnourished children, especially overnourished ones, should be routinely screened for hypocalcaemia because of its high prevalence among them.

Micronutrient gaps during the complementary feeding period in seven countries in Southeast Asia: A Comprehensive Nutrient Gap Assessment

The complementary feeding period is a critical stage of child development when micronutrient needs are high and challenging to meet. Understanding if specific micronutrient gaps exist during this period is critical for effective programming. A Comprehensive Nutrient Gap Assessment (CONGA) was conducted in seven countries in Southeast Asia to estimate gaps in micronutrients commonly lacking in the diets of children aged 6-23 months and to establish the certainty of available evidence for each identified gap. Sixty-eight evidence sources were identified during this analysis, and 310 micronutrient-specific data points were identified across all seven countries. Data points varied in recency, representativeness and evidence type. The CONGA methodology enabled the estimation of a gap burden rating for each micronutrient in each country, as well as a rating of their evidence certainty. Micronutrient gaps were identified in vitamin D, zinc and iron and a potential gap was identified in calcium during the complementary feeding period in the region. Evidence relevant to intake and deficiency of folate, vitamin B12 , thiamine, niacin, vitamin C and vitamin B6 was limited across the region. Proven strategies to address these gaps include increasing the availability and consumption of nutrient-dense foods, micronutrient supplementation, large-scale fortification of staple foods and condiments and point-of-use fortification through multiple micronutrient powders and fortified speciality foods. More recent data on micronutrient availability, intake and deficiency is urgently needed in Southeast Asia.

Endocrine Health and Health Care Disparities in the Pediatric and Sexual and Gender Minority Populations: An Endocrine Society Scientific Statement

Endocrine care of pediatric and adult patients continues to be plagued by health and health care disparities that are perpetuated by the basic structures of our health systems and research modalities, as well as policies that impact access to care and social determinants of health. This scientific statement expands the Society's 2012 statement by focusing on endocrine disease disparities in the pediatric population and sexual and gender minority populations. These include pediatric and adult lesbian, gay, bisexual, transgender, queer, intersex, and asexual (LGBTQIA) persons. The writing group focused on highly prevalent conditions-growth disorders, puberty, metabolic bone disease, type 1 (T1D) and type 2 (T2D) diabetes mellitus, prediabetes, and obesity. Several important findings emerged. Compared with females and non-White children, non-Hispanic White males are more likely to come to medical attention for short stature. Racially and ethnically diverse populations and males are underrepresented in studies of pubertal development and attainment of peak bone mass, with current norms based on European populations. Like adults, racial and ethnic minority youth suffer a higher burden of disease from obesity, T1D and T2D, and have less access to diabetes treatment technologies and bariatric surgery. LGBTQIA youth and adults also face discrimination and multiple barriers to endocrine care due to pathologizing sexual orientation and gender identity, lack of culturally competent care providers, and policies. Multilevel interventions to address these disparities are required. Inclusion of racial, ethnic, and LGBTQIA populations in longitudinal life course studies is needed to assess growth, puberty, and attainment of peak bone mass. Growth and development charts may need to be adapted to non-European populations. In addition, extension of these studies will be required to understand the clinical and physiologic consequences of interventions to address abnormal development in these populations. Health policies should be recrafted to remove barriers in care for children with obesity and/or diabetes and for LGBTQIA children and adults to facilitate comprehensive access to care, therapeutics, and technological advances. Public health interventions encompassing collection of accurate demographic and social needs data, including the intersection of social determinants of health with health outcomes, and enactment of population health level interventions will be essential tools.

Clinical spectrum and diagnostic challenges of vitamin D dependent rickets type 1A (VDDR1A) caused by CYP27B1 mutation in resource limited countries

OBJECTIVES

Vitamin D dependent rickets type 1A (VDDR1A) is a rare autosomal recessive condition due to inactivating mutation of CYP27B1. It mimics clinically, biochemically and rediologically to nutritional and hypophosphatemic rickets. In developing countries like Pakistan, VDDR1A is often misdiagnosed as nutritional rickets or hypophosphatemic rickets due lack of free access to 1,25 (OH) 2 D level and genetic testing. This study was aimed to determine the clinical spectrum and diagnostic challenges of VDDR1A due to CYP27B1 mutation in developing countries.

METHODS

Retrospective review of all cases of VDDR1A due to CYP27B1 mutation over a period of two years presenting in the Pediatric Endocrine clinic of Hameed Latif Hospital, Lahore, Pakistan.

RESULTS

Six cases of VDDR1A (4 males) were identified. Mean age of clinical manifestation was 14 (9-24) months. Mean age of presentation to endocrine department was 5.5 (1.5-11.8) years. Growth failure and bony deformities were the most common presentation (n=6), followed by repeated diarrheas and abdominal distension (n=3) and recurrent fractures (n=1). All cases shared same biochemical profile of low/normal calcium, hypophosphatemia, raised alkaline phosphatase, raised PTH, normal/high 25(OH)D and tubular reabsorption of phosphate (TRP) <85%. Patients treated with calcitriol showed rapid healing as compared to those treated with 1-alfacalcidol.

CONCLUSIONS

We should have a high index of suspicion of VDDR1A in rickets not responding to cholecalciferol therapy.

Nutrition in school-age children: a rationale for revisiting priorities

Middle childhood and early adolescence have received disproportionately low levels of scientific attention relative to other life stages, especially as related to nutrition and health. This is partly due to the justified emphasis on the first 1000 days of life, and the idea that early deficits and consequences may not be fully reversible. In addition, these stages of life may superficially appear less "eventful" than infancy or late adolescence. Finally, there has been historical ambiguity and inconsistency in terminology, depending on whether viewing "childhood" through physiologic, social, legal, or other lenses. Nevertheless, this age bracket, which encompasses most of the primary education and basic schooling years for most individuals, is marked by significant changes, inflection points, and sexually driven divergence in somatic and brain growth and development trajectories. These constitute transformative changes, and thus middle childhood and early adolescence represents a major and last opportunity to influence long-term health and productivity. This review highlights the specificities of growth and development in school age, with a focus on middle childhood and early adolescence (5 years-15 years of age, for the purposes of this review), the role of nutrition, the short- and long-term consequences of inadequate nutrition, and the current global status of nutrition in this age group. Adequate attention and emphasis on nutrition in the school-age years is critical: (a) for maintaining an adequate course of somatic and cognitive development, (b) for taking advantage of this last major opportunity to correct deficits of undernutrition and "catch-up" to normal life course development, and (c) for addressing the nutritional inadequacies and mitigating the longer-term consequences of overnutrition. This review summarizes and provides a rationale for prioritizing nutrition in school-age children, and for the need to revisit priorities and focus on this part of the life cycle to maximize individuals' potential and their contribution to society.

Food Insecurity, Dietary Intakes, and Eating Behaviors in a Convenience Sample of Toronto Youth

BACKGROUND

Food insecurity has been shown to be associated with poor dietary quality and eating behaviors, which can have both short- and long-term adverse health outcomes in children. The objective was to investigate the food security status, dietary intakes, and eating behaviors in a convenience sample of youth participating in the Maple Leaf Sports Entertainment LaunchPad programming in downtown Toronto, Ontario.

METHODS

Youth aged 9-18 years were recruited to participate in the study. Food security status, dietary intakes, and eating behaviors were collected using parent- or self-reported questionnaires online.

RESULTS

Sixty-six youth (mean ± SD: 11.7 ± 1.9 years) participated in the study. The prevalence of household food insecurity was higher than the national average with at least one child under 18 years of age (27.7% vs. 16.2%). Dietary intake patterns were similar to the national trends with low intakes of fiber, inadequate intakes of calcium and vitamin D; and excess intakes of sodium, added sugar, and saturated fat. Despite a low prevalence of poor eating habits, distracted eating was the most frequently reported poor eating habit.

CONCLUSIONS

Although youth were at high risk for experiencing household food insecurity, inadequate dietary intake patterns were similar to the national trends. Our findings can be used to develop future programming to facilitate healthy dietary behaviors appropriate for the target community.

Calcium deficiency worldwide: prevalence of inadequate intakes and associated health outcomes

Dietary calcium deficiency is considered to be widespread globally, with published estimates suggesting that approximately half of the world's population has inadequate access to dietary calcium. Calcium is essential for bone health, but inadequate intakes have also been linked to other health outcomes, including pregnancy complications, cancers, and cardiovascular disease. Populations in low- and middle-income countries (LMICs) are at greatest risk of low calcium intakes, although many individuals in high-income countries (HICs) also do not meet recommendations. Paradoxically, many LMICs with lower calcium intakes show lower rates of osteoporotic fracture as compared with HICs, though data are sparse. Calcium intake recommendations vary across agencies and may need to be customized based on other dietary factors, health-related behaviors, or the risk of calcium-related health outcomes. The lack of standard methods to assess the calcium status of an individual or population has challenged efforts to estimate the prevalence of calcium deficiency and the global burden of related adverse health consequences. This paper aims to consolidate available evidence related to the global prevalence of inadequate calcium intakes and associated health outcomes, with the goal of providing a foundation for developing policies and population-level interventions to safely improve calcium intake and status where necessary.

Overview of Traditional and Environmental Factors Related to Bone Health

Bone mass in adulthood depends on growth and mineralization acquired during childhood and adolescence. It is well known that these stages of life are crucial for bone development, where genetic, nutritional, hormonal, and lifestyle factors play a significant role. Bone loss is normally a natural and slow process that begins years later after the peak bone mass is achieved and continues throughout the lifespan. Lifestyle choices in childhood and adolescence such as minimal physical activity, excessive caffeine or carbonated beverages intake, malnutrition, cigarette use, or high alcohol consumption and other factors like environmental pollutants can also negatively affect bone health and accelerate the bone loss process. The aim of this work is an overview of risk factors associated with inadequate bone health in early life.

How Much Does Serum 25(OH)D Improve by Vitamin D Supplement and Fortified Food in Children? A Systematic Review and Meta-Analysis

OBJECTIVES

This study was conducted to respond certain important questions regarding the efficacy of vitamin D fortification and supplementation in children using a meta-analytical approach.

METHODS

MEDLINE, PubMed, Embase, Cochrane Library, and Google Scholar were searched, and 2341 studies were found in a preliminary search. After screening of titles and abstracts, 31 studies were selected.

RESULTS

Significant raises in circulating 25-hydroxy vitamin D (25(OH)D) concentrations were observed in both groups that took vitamin D supplement (mean difference [MD] 28.7, 95% confidence interval [CI] 22.5-34.9) and vitamin D-fortified foods (MD 20.29, 95% CI 13.3-27.2). The meta-regression revealed a significant association between age of participants (B -1.4, 95% CI -2.8, -0.02, P = 0.047) and dose of vitamin D (B 0.007, 95% CI 0.003, 0.01, P < 0.001), with the effect on serum 25(OH)D concentrations. The analysis showed that serum 25(OH)D concentration increases by 0.7 nmol/L for every 100 IU of vitamin D intake after adjustment for age, baseline serum 25(OH)D and latitude which is far less than the reported amount in adults.

CONCLUSIONS

Altogether, these findings indicate that in a mass vitamin D fortification program, circulating 25(OH)D concentration response in children may be lower in children than in adults and vitamin D supplementation may still be needed in this subpopulation.

Is dietary deficiency of calcium a factor in rickets? Use of current evidence for our understanding of the disease in the past

OBJECTIVE

Rickets is considered an indicator of vitamin D deficiency in palaeopathology, but a strand of biomedical thought maintains that dietary calcium deficiency may sometimes play a part in its causation. Our aim is to evaluate the extent to which low calcium intake should be considered as a factor in biocultural interpretations of rickets.

METHODS

We assess published modern epidemiological studies that provide primary data to support claims for a role for dietary calcium deficiency in rickets. We also consider how we might identify, via indicators of calcium intake, populations at risk of calcium deficiency in the past.

RESULTS

Support for dietary calcium deficiency as a cause of rickets is equivocal. Direct measurement of dietary calcium in the past is not possible, but exposure to risk factors for low calcium intake can to some extent be identified.

CONCLUSION

Whilst there is little evidence to alter the view that rickets is essentially an indicator of a population's vitamin D status, occasionally, in very low calcium intake groups, dietary calcium deficiency may play a synergistic role by accentuating the need for vitamin D.

SIGNIFICANCE

The notion that dietary calcium deficiency may be a cause of rickets appears to be gaining currency in bioarchaeological studies. This paper shows that it is unusual for this to be the case, and even then the role of vitamin D remains crucial.

LIMITATIONS

This paper attempts to summarise the current state of biomedical study in an area that is subject to continuing investigation.

An Update on Vitamin D Deficiency Status in Malaysia

Vitamin D is essential for maintaining serum calcium levels, ensuring sufficient bone mineralization, immunomodulatory properties, and a protective effect on the cardiovascular system, renal disease, cancer, as well as in pregnancy. Vitamin D deficiency is prevalent worldwide, and it is not related to a country's development index. However, the data on vitamin D deficiencies are primarily taken from out-of-date, small-scale studies on target age groups or specific diseases, rather than from large-scale, population-based surveys. In Malaysia, for the past 16 years, studies were conducted involving adult men and women, pregnant women, postmenopausal women, adolescent, and children especially with specific diseases such as spina bifida, epilepsy, chronic liver disease, and atopic dermatitis. Only a few large surveys were conducted involving children and adolescents. Across the specific target population studied, vitamin D deficiency and insufficiency were seen particularly among females, Indians, and those of Malay ethnicity. This is related to widely known causes of vitamin D deficiency such as skin type (melanin) and sun avoidant lifestyles that include covering clothes, largely practiced by Malay Muslims in Malaysia. Other related causes or the high-risk groups are breastfed infants, the elderly, the obese, those on medications, and those characterized by fat malabsorption and geophysical factors. Vitamin D deficiency can be managed with pharmacological or non-pharmacological approaches, depending on the severity. The objective is to raise serum vitamin D to a normal level, hence, relieving the symptoms and reducing the adverse health outcomes. Despite no clear guidelines in treating vitamin D deficiency in Malaysia, this condition can be prevented with taking adequate vitamin D in food resources, sun exposure, or supplementation. Special attention should be given to high-risk groups including infants, obese patients, and the elderly.

An Assessment of the Nutritional Value of the Preschool Food Rations for Children from the Wroclaw District, Poland—The Case of a Big City

The evaluation of nutrition is an essential element of preventing chronic diseases and can be used to determine nutritional recommendations. A child spends about 7–8 h a day in a kindergarten; therefore, meals served there should be balanced appropriately to ensure the full psychophysical development of the young organism. At preschool age, children develop eating habits that can have life-long effects. Based on 10-day menus, the study aimed to estimate the energy and nutritional value of children’s diets at four randomly selected kindergartens in the Wroclaw district, Poland. In total, 80 menus were analyzed (40 for summer and 40 for autumn). The data from kindergartens were analyzed based on the Diet 6D computer program. Regardless of the kindergarten, the analyzed food rations showed irregularities related to excessive supplies (in reference to the dietary recommendations) of sucrose, fiber, salt, magnesium, and vitamin A. The preschool food rations did not cover demands with respect to PUFA n-3, PUFA-n-6, calcium, and vitamin D. The observed irregularities confirm the need to monitor the content of energy and nutrients in preschool menus to be able to correct any dietary errors.

The genetic and epigenetic contributions to the development of nutritional rickets

Nutritional rickets is an important disease in global health. Although nutritional rickets commonly manifests as bony deformities, there is an increased risk of life-threatening seizures secondary to hypocalcaemia. Dietary vitamin D deficiency is associated with the development of nutritional rickets among children and infants. This is especially true in populations of darker skinned individuals in high-latitude environments due to decreased ultraviolet light exposure, and in populations in tropical and subtropical climates due to cultural practices. A growing body of evidence has demonstrated that genetic factors might influence the likelihood of developing nutritional rickets by influencing an individual's susceptibility to develop deficiencies in vitamin D and/or calcium. This evidence has been drawn from a variety of different techniques ranging from traditional twin studies to next generation sequencing techniques. Additionally, the role of the epigenome in the development of rickets, although poorly understood, may be related to the effects of DNA methylation and non-coding RNAs on genes involved in bone metabolism. This review aims to provide an overview of the current evidence that investigates the genetic and epigenetic determinants of nutritional rickets.

Rickets Due to Severe Vitamin D and Calcium Deficiency During the COVID-19 Pandemic in Malaysia

Patient: Female, 22-month-old

Final Diagnosis: Nutritional rickets

Symptoms: Bowing of legs

Medication:—

Clinical Procedure:—

Specialty: Pediatrics and Neonatology

Effects of Calcium and Vitamin D Co-supplementation on the Lipid Profile: A Systematic Review and Meta-analysis

PURPOSE

Calcium and vitamin D co-supplementation is common and widely used, but randomized, controlled trials (RCTs) have yielded inconclusive results concerning its impact on the serum lipid profile.

METHODS

A comprehensive literature search of Medline, Web of Science, Scopus, Embase, Cochrane Central Register of Controlled Trials, and clinical trial registry databases was conducted to identify placebo-controlled RCTs that were published through September 2020 and that evaluated the impact of calcium and vitamin D co-supplementation on total cholesterol (TC), triglycerides (TGs), low- and very-low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C). Standardized mean differences (SMDs) were pooled using random-effects meta-analysis models.

FINDINGS

Thirteen studies in a total of 2304 participants met the inclusion criteria. Calcium and vitamin D co-supplementation was associated with significant reductions in both TC (SMD, -0.81; 95% CI, -1.35 to -0.27; I² = 94.6%) and TGs (SMD, -0.50; 95% CI, -0.91 to -0.08; I² = 91.5%), and with a significant increase in HDL-C (SMD, 1.22; 95% CI, 0.60 to 1.83; I² = 95.4%). However, calcium and vitamin D co-supplementation were not found to be associated with significantly decreased low-density lipoprotein cholesterol (SMD, -0.39; 95% CI, -0.78 to 0.01; I² = 90.1%) or very-low-density lipoprotein cholesterol (SMD, -0.01; 95% CI, -0.70 to 0.69; I² = 82.3%).

IMPLICATIONS

The findings from the present systematic review and meta-analysis suggest that calcium and vitamin D co-supplementation has a beneficial effect on TC, TG, and HDL-C. Larger-scale, well-designed RCTs are needed to clarify the effect of calcium and vitamin D co-supplementation on all lipid-profile components.

Serum 25-hydroxyvitamin D requirements to prevent nutritional rickets in Nigerian children on a low-calcium diet-a multivariable reanalysis

BACKGROUND

Nutritional rickets is believed to result from the interaction of inadequate serum 25-hydroxyvitamin D [25(OH)D] concentration and dietary calcium intake, but this interaction has not been confirmed in children with rickets. Determining the vitamin D requirements to prevent nutritional rickets has been thwarted by inconsistent case definition, inadequate adjustment for calcium intake and other confounders, and 25(OH)D assay variability.

OBJECTIVES

To model the 25(OH)D concentration associated with nutritional rickets in calcium-deprived Nigerian children, adjusted for confounding factors, and develop a general approach to define vitamin D status while accounting for calcium intake.

METHODS

Logistic regression was used to model the association of serum 25(OH)D with having rickets adjusted for calcium intake in a reanalysis of a case-control study in Nigerian children. The matching variables age, sex, weight-for-age z score, and 4 additional significant variables were selected [religion, age began walking, phosphorus intake, and the 25(OH)D × calcium intake interaction] using a rigorous 7-step algorithm.

RESULTS

Cases had significantly (P < 0.0001) lower mean ± SD 25(OH)D than controls (33 ± 13 compared with 51 ± 16 nmol/L, respectively), whereas cases and controls had similarly (P = 0.81) low mean dietary calcium intakes (216 ± 88 and 213 ± 95 mg/d, respectively). There was a significant interaction between 25(OH)D and calcium intake [coefficient (95% CI): -0.0006 (-0.0009, -0.0002)]. Accordingly, as calcium intake increased from 130 to 300 mg/d, the adjusted odds of having rickets decreased dramatically with increasing 25(OH)D such that at 200 mg/d, the adjusted odds of having rickets at 47.5 nmol/L was 0.80, whereas it was 0.2 at 62.5 nmol/L. Moreover, at a calcium intake of 300 mg/d, the adjusted odds was 0.16 at a 25(OH)D concentration of 47.5 nmol/L and 0.02 at 62.5 nmol/L.

CONCLUSIONS

The vitamin D requirement to prevent nutritional rickets varies inversely with calcium intake and vice versa. Also, application of multivariable modeling is essential in defining vitamin D requirements.

The Safety of a Vegan Diet During Pregnancy

There is an increasing number of people who go vegetarian. Some young parents also switch to this diet. The safety of vegetarian diets, especially vegan diets, is very important, especially during pregnancy. Unfortunately, reference publications do not provide coherent data on the safety of vegetarian diets during pregnancy. On the one hand, the vegan diet has advantages because it reduces the risk of heart disease and gestational diabetes. On the other hand, vegetarians/vegans should be aware of potential deficiencies of some nutrients (iron, zinc, vitamin B12, vitamin D, omega-3 fatty acids, calcium, iodine) and the clinical consequences for the fetus. For example, iron deficiency may affect cognitive abilities, behavior, intelligence and increase the risk of preterm birth and low birth weight of infants. Plant food contains non-haem iron with variable absorption. Therefore, the vegan diet should include nutrients increasing the bioavailability of iron, e.g. ascorbic acid, carotene and retinol. Due to the fact that animal food is the main source of vitamin B12, vegans are at a very high risk of vitamin B12 deficiency, which will affect the infant’s weight at birth. Low level of vitamin D, which is prevalent in animal food, is the most common deficiency among vegans and lacto-ovo vegetarians. This vitamin prevents gestational diabetes, reduces insulin resistance and guarantees normal function of the musculoskeletal system. Zinc deficiency during pregnancy may lead to preterm birth, neural tube defects or even miscarriage. In view of the clinical consequences of potential deficiencies of nutrients, the vegetarian/vegan diet should be well balanced.

Nutritional rickets & osteomalacia: A practical approach to management

Defective mineralization of the growth plate and preformed osteoid result in rickets and osteomalacia, respectively. The leading cause of rickets worldwide is solar vitamin D deficiency and/or dietary calcium deficiency collectively termed as nutritional rickets. Vitamin D deficiency predominates in high-latitude countries in at-risk groups (dark skin, reduced sun exposure, infants and pregnant and lactating women) but is emerging in some tropical countries due to sun avoidance behaviour. Calcium deficiency predominates in tropical countries, especially in the malnourished population. Nutritional rickets can have devastating health consequences beyond bony deformities (swollen wrist and ankle joints, rachitic rosary, soft skull, stunting and bowing) and include life-threatening hypocalcaemic complications of seizures and, in infancy, heart failure due to dilated cardiomyopathy. In children, diagnosis of rickets (always associated with osteomalacia) is confirmed on radiographs (cupping and flaring of metaphyses) and should be suspected in high risk individuals with the above clinical manifestations in the presence of abnormal blood biochemistry (high alkaline phosphatase and parathyroid hormone, low 25-hydroxyvitamin D and calcium and/or low phosphate). In adults or adolescents with closed growth plates, osteomalacia presents with non-specific symptoms (fatigue, malaise and muscle weakness) and abnormal blood biochemistry, but only in extreme cases, it is associated with radiographic findings of Looser's zone fractures. Bone biopsies could confirm osteomalacia at earlier disease stages, for definitive diagnosis. Treatment includes high-dose cholecalciferol or ergocalciferol daily for a minimum of 12 wk or stoss therapy in exceptional circumstances, each followed by lifelong maintenance supplementation. In addition, adequate calcium intake through diet or supplementation should be ensured. Preventative approaches should be tailored to the population needs and incorporate multiple strategies including targeted vitamin D supplementation of at-risk groups and food fortification with vitamin D and/or calcium. Economically, food fortification is certainly the most cost-effective way forward.

Modern India and Dietary Calcium Deficiency-Half a Century Nutrition Data-Retrospect-Introspect and the Road Ahead

Calcium and vitamin D are inseparable nutrients required for bone health. In the past half a century, the dietary calcium intake of rural, tribal, and urban India has declined. Though India is the largest producer of milk and cereals, the major source of calcium in India is through non-dairy products. The highest intake of cereals and lowest intake of milk & milk products was observed in rural and tribal subjects whereas, the intake of cereals, milk & milk products were similar in both urban and metropolitan subjects. One of the reasons for lower calcium intake was the proportion of calcium derived from dairy sources. Over the past half a century, the average 30-day consumption of cereals in the rural and urban population has declined by 30%. The Per Capita Cereal Consumption (PCCC)has declined despite sustained raise in Monthly Per capita Consumption Expenditure (MPCE) in both rural and urban households. The cereal consumption was the highest in the lowest income group, despite spending smaller portion of their income, as cereals were supplied through public distribution system (PDS). About 85% of the Indian population are vitamin D deficient despite abundant sunlight. Dietary calcium deficiency can cause secondary vitamin D deficiency. Though India as a nation is the largest producer of milk, there is profound shortage of calcium intake in the diet with all negative consequences on bone health. There is a decline in dietary calcium in the background of upward revision of RDI/RDA. There is a gap in the production-consumption-supply chain with respect to dietary calcium. To achieve a strong bone health across India, it is imperative to have population based strategies addressing different segments including supplementing dietary/supplemental calcium in ICDS, mid-day-meals scheme, public distribution system, educational strategies. Other measures like mass food fortification, biofortification, bioaddition, leveraging digital technologies, investments from corporate sector are some measures which can address this problem. India is a vast country with diverse social, cultural and dietary habits. No single measure can address this problem and requires a multi-pronged strategic approach to tackle the dietary calcium deficiency to achieve strong bone health while solving the problem of nutritional deficiency.

Micronutrient gaps during the complementary feeding period in 6 countries in Eastern and Southern Africa: a Comprehensive Nutrient Gap Assessment

Insufficient quantity and inadequate quality of foods in early life are key causes of all forms of malnutrition. Identification of nutrient and dietary gaps in the diets of infants and young children is essential to inform policies and programs designed to improve child diets. A Comprehensive Nutrient Gap Assessment was used to assess the public health significance of nutrient gaps during the complementary feeding period and to identify evidence gaps in 6 countries in Eastern and Southern Africa. Important gaps were identified in iron, vitamin A, zinc, and calcium and, to a lesser extent, vitamin B12 and folate. The best whole-food sources of these micronutrients available in part or all of the countries studied include beef liver, chicken liver, small dried fish, beef, and eggs. Investment is needed in many countries to collect data on micronutrient biomarkers and dietary intake. Strategic actions to improve child diets will require engagement and intervention across relevant systems to accelerate progress on improving the diets of infants and young children.

Micronutrient gaps during the complementary feeding period in South Asia: A Comprehensive Nutrient Gap Assessment

Micronutrient malnutrition is a key driver of morbidity and mortality for millions of children in South Asia. Understanding the specific micronutrients lacking in the diet during the complementary feeding period is essential for addressing undernutrition caused by inadequate diets. A Comprehensive Nutrient Gap Assessment was used to synthesize diverse evidence and estimate the public health significance of complementary-feeding micronutrient gaps and identify evidence gaps in 8 countries in South Asia. There were important gaps across the region in iron, zinc, vitamin A, folate, vitamin B12, and, to a lesser extent, calcium and vitamin C. The most nutrient-dense, whole-food sources of these micronutrients include liver, small fish, eggs, ruminant meat, and dark leafy greens. Investment is needed in some countries to collect data on micronutrient biomarkers and dietary intakes. A food systems approach is essential for improving child diets and reducing malnutrition, which affects millions of children, their futures, and society at large across South Asia and beyond.

Calcium repletion to rats with calcipenic rickets fails to recover bone quality: A calcipenic "memory"

Calcipenic rickets is prevalent in underprivileged children in developing countries. Calcipenic rickets resulting from dietary calcium (Ca) deficiency decreases bone mass and deteriorates bone microstructure in humans. The effect of dietary Ca replenishment (CaR) on rachitic bones in animal models depends on the amount, critical period and duration of replenishment, however, the extent of recovery in various bone parameters including bone quality remains unclear. We investigated the effect of CaR in rat skeleton after inducing calcipenic rickets. Female SD rats (postnatal 28 days/P28) were rendered calcipenic by feeding calcium deficient (CaD) diet (0.1% Ca) till P70 while control SD rats were fed Ca sufficient diet (0.8% Ca). At P70, calcipenic rats were switched to 0.8% Ca diet till P150 for one group and P210 for another group (endpoint). The CaD groups received 0.1% Ca diet throughout the study (P210). In the CaD groups, serum Ca and phosphate, and bone mineral density (BMD) were significantly decreased whereas serum alkaline phosphatase (ALP), iPTH and CTX-1 were increased compared to age-matched controls. Moreover, at the endpoint, the CaD group had reduced bone mass, surface referent bone formation parameters, tissue mineralization and strength accompanied by the increased osteoid thickness and microarchitectural decay (measured by trabecular geometric parameters) with poor crystal packing. The CaR group showed complete recovery in serum Ca, iPTH, ALP and CTX-1, and BMD, however, the bone quality parameters including bone strength, microarchitectural decay, tissue mineralization, and crystallinity were incompletely restored. Decreased surface referent bone formation and increased unmineralized bones (osteoid) indicative of osteomalacia were also observed in the CaR group at P210 compared with control despite prolonged replenishment. We conclude that a prolonged Ca repletion following the induction of calcipenic rickets in rats although shows the recovery of biochemical measures of bone metabolism and bone mass, however, the bone quality remains compromised. This suggests that a "memory" of calcipenia occurring at the early growth stage persists in the skeleton of adult rats despite a prolonged Ca replenishment.

Composition of nutrients, heavy metals, polycyclic aromatic hydrocarbons and microbiological quality in processed small indigenous fish species from Ghana: Implications for food security

The triple burden of malnutrition is an incessant issue in low- and middle-income countries, and fish has the potential to mitigate this burden. In Ghana fish is a central part of the diet, but data on nutrients and contaminants in processed indigenous fish species, that are often eaten whole, are missing. Samples of smoked, dried or salted Engraulis encrasicolus (European anchovy), Brachydeuterus auritus (bigeye grunt), Sardinella aurita (round sardinella), Selene dorsalis (African moonfish), Sierrathrissa leonensis (West African (WA) pygmy herring) and Tilapia spp. (tilapia) were collected from five different regions in Ghana. Samples were analyzed for nutrients (crude protein, fat, fatty acids, several vitamins, minerals, and trace elements), microbiological quality (microbial loads of total colony counts, E. coli, coliforms, and Salmonella), and contaminants (PAH4 and heavy metals). Except for tilapia, the processed small fish species had the potential to significantly contribute to the nutrient intakes of vitamins, minerals, and essential fatty acids. High levels of iron, mercury and lead were detected in certain fish samples, which calls for further research and identification of anthropogenic sources along the value chains. The total cell counts in all samples were acceptable; Salmonella was not detected in any sample and E. coli only in one sample. However, high numbers of coliform bacteria were found. PAH4 in smoked samples reached high concentrations up to 1,300 μg/kg, but in contrast salted tilapia samples had a range of PAH4 concentration of 1 μg/kg to 24 μg/kg. This endpoint oriented study provides data for the nutritional value of small processed fish as food in Ghana and also provides information about potential food safety hazards. Future research is needed to determine potential sources of contamination along the value chains in different regions, identify critical points, and develop applicable mitigation strategies to improve the quality and safety of processed small fish in Ghana.

Sociodemographic disparity in the nutritional status among children and adolescents in Zhejiang Province

OBJECTIVE

To explore the sociodemographic disparity in the nutritional status including BMI, vitamin D and vitamin A status among children and adolescents in Zhejiang Province.

METHODS

Weight, height serum 25-hydroxyvitamin D, and serum retinol were assessed in 2818 children and adolescents (6-17 years of age), using ten investigation sites in Zhejiang Province including urban and rural areas data from the China National Nutritional Study 2016-2017, which is a nationally representative cross-sectional study, to form provincial representative sample of Zhejiang Province. Sociodemographic disparity was explored.

RESULTS

The prevalence of low weight, eutrophic, overweight and obese were 6.7%, 70.4%, 11.6%, and 11.2%, respectively. Significant difference was observed on BMI between males and females (P < 0.05), and between urban and rural areas (P < 0.05). The prevalence of vitamin D deficiency, inadequacy, normal and appropriate were 1.8%, 34.9%, 46.4% and 16.9%, respectively. Significant difference was observed on the concentration of 25-hydroxyvitamin D (25(OH)D) both between genders and between living areas (P < 0.05). The prevalence of vitamin A deficiency, marginal deficiency and appropriate were 4.5%, 24.7%, and 70.9%, respectively. Significant difference was observed on the concentration of retinol between living area (P < 0.05).

CONCLUSIONS

Overweight and obesity, deficiency and inadequacy of vitamin D, deficiency and marginal deficiency of vitamin A were prevalent among children and adolescents. There were disparities between genders and between living areas on the nutritional status. Regional and sex-specific guidelines and public health policies for children and adolescent nutrition are needed.

Provincial Dietary Intake Study (PDIS): Micronutrient Intakes of Children in a Representative/Random Sample of 1- to <10-Year-Old Children in Two Economically Active and Urbanized Provinces in South Africa

In 1999, the National Food Consumption Survey found serious risk of dietary deficiency for a number of micronutrients in 1- to 9-year-old children in South Africa. To address these shortfalls, fortification with vitamin A, thiamine, riboflavin, niacin, vitamin B6, folic acid, iron and zinc of maize meal and bread flour was made mandatory in 2003. The aim of this study was to examine micronutrient intakes of 1- to <10-year-old children after nearly 20 years of fortification in two of the most urbanized and economically active provinces, Gauteng (GTG) and the Western Cape (WC). A multistage stratified cluster random sampling design and methodology was used. Households were visited by fieldworkers who interviewed caregivers and obtained dietary intake data by means of a multiple-pass 24-h recall. Two additional 24-h recalls were completed among a nested sample of 146 participants to adjust the single 24-h recall data of the total sample using the National Cancer Institute Method. Results show that median intake of all the fortification nutrients were above the estimated average requirement (EAR), with the only concern being folate in the WC. Between a quarter and a third of children in the WC, where maize porridge intake was significantly lower than in GTG, had a folate intake below the EAR. Nutrients that are not included in the fortification mix that remain a serious concern are calcium and vitamin D, with intake of dairy and vitamin D sources being very limited in both provinces. The improvement in micronutrient intakes of children is encouraging, however the outstanding nutrient deficiency risks need attention.

Diagnosis and Management of Vitamin D Dependent Rickets

The term "vitamin D dependent rickets" describes a group of genetic disorders that are characterized by early-onset rickets due to the inability to maintain adequate concentrations of active forms of vitamin D or a failure to respond fully to activated vitamin D. Although the term is now admittedly a pathophysiological misnomer, there remains clinical relevance for its continued use, as patients have a lifelong "dependency" on administration of specialized regimens of vitamin D replacement. This review provides an update on the molecular bases for the three forms of vitamin D dependent rickets, and summarizes current protocols for management of affected subjects.

Bone mass and dietary intake in children and adolescents with type 1 diabetes mellitus

OBJECTIVES

To evaluate the bone mineral density (BMD) in children/adolescents with type 1 diabetes mellitus (T1DM) and its association with the nutritional intake, metabolic control, and physical activity level of this population.

METHODS

Study including 34 patients with T1DM and 17 controls. Assessments included the participants disease history, intake of macronutrient, calcium, phosphorus and magnesium, physical activity level, total body and lumbar spine BMD and serum levels of glycated hemoglobin, vitamin D, calcium, phosphorus, magnesium, osteocalcin and C-terminal telopeptide.

RESULTS

Total body and lumbar spine BMD z-scores were normal in all but two participants in the T1DM group. The T1DM group had significantly lower total body BMD z-score values (p < 0.001) and levels of osteocalcin, C-terminal telopeptide, calcium, phosphorus, and magnesium. Intake of macronutrients and calcium was inadequate in both groups. Participants in the T1DM group were more sedentary (88%) and had inadequate metabolic control (91%) and low vitamin D levels (82%). Bone mass in the T1DM group was influenced by body mass index (BMI), pubertal stage, disease duration, calcium intake, and physical activity level.

CONCLUSIONS

Bone mass in patients with T1DM was adequate but lower than controls and was influenced by BMI, pubertal stage, disease duration, calcium consumption, and physical activity level.

Nutritional rickets: Historic overview and plan for worldwide eradication

Rickets was first described in great detail in the mid 17th century and was affecting a great number of children in major European cities. The disease, however, existed already in the Roman times. The etiology of this disease remained enigmatic until the 1920s when two different mechanisms, lack of exposure to sunlight and lack of a dietary factor were finally solved by the discovery of vitamin D and its dual origin. Soon thereafter, the implementation of vitamin D supplementation for all infants and small children largely eliminated nutritional rickets in Europe and North America. It took nearly a century to elucidate the complex chemistry, metabolism, mode and spectrum of activity of the vitamin D endocrine system. Nutritional rickets, whether due to simple vitamin D or calcium deficiency or both, remains widely ravaging many infants and children around the world. Asian countries and the Middle East are mainly confronted with vitamin D deficiency whereas many African and some Asian countries face calcium deficiency rickets. Immigrants and refugees or in general people with a darker skin living in moderate climate zone are also confronted with this disease. There is great consensus how this disease could be prevented or cured. In collaboration with most international professional societies, we prepare a memorandum, in line with the successful battle against iodine deficiency disorders, to convince the World Health Organization and its member states to start an implementation program to eradicate nutritional rickets by 2030.

Prevalence of vitamin D deficiency in Africa: a systematic review and meta-analysis

BACKGROUND

Vitamin D deficiency is associated with non-communicable and infectious diseases, but the vitamin D status of African populations is not well characterised. We aimed to estimate the prevalence of vitamin D deficiency in children and adults living in Africa.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Web of Science, Embase, African Journals Online, and African Index Medicus for studies on vitamin D prevalence, published from database inception to Aug 6, 2019, without language restrictions. We included all studies with measured serum 25-hydroxyvitamin D (25[OH]D) concentrations from healthy participants residing in Africa. We excluded case reports and case series, studies that measured 25(OH)D only after a clinical intervention, and studies with only a meeting abstract or unpublished material available. We used a standardised data extraction form to collect information from eligible studies; if the required information was not available in the published report, we requested raw data from the authors. We did a random-effects meta-analysis to obtain the pooled prevalence of vitamin D deficiency in African populations, with use of established cutoffs and mean 25(OH)D concentrations. We stratified meta-analyses by participant age group, geographical region, and residence in rural or urban areas. The study is registered with PROSPERO, number CRD42018112030.

FINDINGS

Our search identified 1692 studies, of which 129 studies with 21 474 participants from 23 African countries were included in the systematic review and 119 studies were included in the meta-analyses. The pooled prevalence of low vitamin D status was 18·46% (95% CI 10·66-27·78) with a cutoff of serum 25(OH)D concentration less than 30 nmol/L; 34·22% (26·22-43·68) for a cutoff of less than 50 nmol/L; and 59·54% (51·32-67·50) for a cutoff of less than 75 nmol/L. The overall mean 25(OH)D concentration was 67·78 nmol/L (95% CI 64·50-71·06). There was no evidence of publication bias, although heterogeneity was high (I2 ranged from 98·26% to 99·82%). Mean serum 25(OH)D concentrations were lower in populations living in northern African countries or South Africa compared with sub-Saharan Africa, in urban areas compared with rural areas, in women compared with men, and in newborn babies compared with their mothers.

INTERPRETATION

The prevalence of vitamin D deficiency is high in African populations. Public health strategies in Africa should include efforts to prevent, detect, and treat vitamin D deficiency, especially in newborn babies, women, and urban populations.

FUNDING

Wellcome Trust and the DELTAS Africa Initiative.

Modern India and the Tale of Twin Nutrient Deficiency-Calcium and Vitamin D-Nutrition Trend Data 50 Years-Retrospect, Introspect, and Prospect

Vitamin D and calcium are essential nutrients for bone health, to achieve peak bone mass and to preserve bone as age advances. A deficiency in these nutrients casts a long shadow in later life in the form of short/long latency diseases-rickets/osteomalacia/osteoporosis. There is scant review available about the trend of these nutrients in India. For over past half a century, the intake of dietary calcium, milk, milk products, and cereals has declined drastically in the background of upward revision of RDA/RDI in modern India. This is attributed to changing lifestyle, inadequate milk consumption across various socio-economic strata, and shift in dietary intake from cereals to rice and wheat. There is a clear rural-urban divide in consumption of milk, milk products and cereals, a change in dietary habits which magnify the calcium and vitamin D deficiency. Revisiting of RDA guidelines for calcium along with public health measures is required to tackle the morbidity arising due to the deficiency in these nutrients. Any measure to addresses this issue in isolation, without achieving the desired benefits, is a disservice to the population. Population based educational strategies, government measures, leveraging technology, adequate sun exposure and food fortification help in tackling the twin nutrient deficiencies in this diverse country.

Calcium Deficiency Rickets in African Adolescents: Cortical Bone Histomorphometry

Rickets due to dietary calcium deficiency has been well described in black African children, but less is known about this condition in black adolescents. We investigated 26 black adolescents (19 males aged 11 to 19 years and 7 females aged 12 to 15 years) with rachitic leg deformities and 20 controls by routine iliac crest undecalcified cortical bone histomorphometry for disturbances of bone turnover and for mineralization defects, including severity of osteocytic osteolysis (Ot.Olysis) and periosteocytic osteolysis (Peri.Ot.Olysis) of the lacunar‐canalicular space. Serum levels of calcium (sCa), 25‐hydroxyvitamin D (25OHD), 1,25‐dihydroxyvitamin D (1,25(OH)₂D), and total alkaline phosphatase (ALP) were measured. Histomorphometry showed varying degrees of severity of secondary hyperparathyroidism (2⁰ HPT) characterized by hyperosteoidosis, increased erosion, and porosis. Because osteoid was neither being mineralized nor eroded (osteoclasts cannot erode osteoid), it increasingly blocked bone surface needed for osteoclastic resorption. Where osteoid covered >50% of bone surface, osteoid thickness, severity of Ot.Olysis, and extent of Peri.Ot.Olysis increased, sCa and 25OHD declined, and 1,25(OH)₂D and ALP increased. At 80% osteoid cover, bone remodeling had all but ceased, secondary HPT had changed to osteomalacia, and serum biochemical results had deteriorated further. Disease severity was greater in males than in females, likely because males grow faster and for longer than females. In conclusion, this cross‐sectional clinical case study presents cortical bone histomorphometric data of secondary HPT and its transition to osteomalacia in black adolescents with rickets attributable to dietary calcium deficiency. The bone disease was most severe in older adolescent males. Importantly, bone pathology of calcium deficiency rickets in adolescents was not confined to bone surfaces but also manifested at osteocyte level as Ot.Olysis and Peri.Ot.Olysis. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

A systematic review and meta-analysis of prevalence of vitamin D deficiency among adolescent girls in selected Indian states

BACKGROUND:

Vitamin D deficiency among adolescents is an emerging public health priority as adolescence marks a period of rapid growth and the onset of the reproductive phase. However, lack of national prevalence data and intervention strategies is of public health concern.

OBJECTIVE:

The objective of this study was to determine the pooled prevalence of vitamin D deficiency among adolescent girls in selected Indian states.

METHODS:

A systematic literature review was performed using three different search engines. The searches yielded nine eligible articles. Study quality was assessed for 10 different criteria. Meta-analysis was performed to estimate pooled prevalence of vitamin D deficiency among adolescent girls and to assess the heterogeneity among selected studies.

RESULTS:

A sample of n=1352 was used to study prevalence among adolescent girls. The random effects combined estimate for overall prevalence was 25.70% (95% CI 3.89-2137.9). High heterogeneity (tau²=1.71, I²=100%) was observed and seven out of nine studies showed low to moderate risk and two showed high risk of bias. The test for overall effect was observed to be Z=0.77 ( p=0.44).

CONCLUSIONS:

High prevalence of vitamin D deficiency among adolescent girls identifies the need to introduce screening of adolescents and introduce proven public-health interventions such as fortification of foods to address deficiency.

Global prevalence and disease burden of vitamin D deficiency: a roadmap for action in low- and middle-income countries

Vitamin D is an essential nutrient for bone health and may influence the risks of respiratory illness, adverse pregnancy outcomes, and chronic diseases of adulthood. Because many countries have a relatively low supply of foods rich in vitamin D and inadequate exposure to natural ultraviolet B (UVB) radiation from sunlight, an important proportion of the global population is at risk of vitamin D deficiency. There is general agreement that the minimum serum/plasma 25-hydroxyvitamin D concentration (25(OH)D) that protects against vitamin D deficiency-related bone disease is approximately 30 nmol/L; therefore, this threshold is suitable to define vitamin D deficiency in population surveys. However, efforts to assess the vitamin D status of populations in low- and middle-income countries have been hampered by limited availability of population-representative 25(OH)D data, particularly among population subgroups most vulnerable to the skeletal and potential extraskeletal consequences of low vitamin D status, namely exclusively breastfed infants, children, adolescents, pregnant and lactating women, and the elderly. In the absence of 25(OH)D data, identification of communities that would benefit from public health interventions to improve vitamin D status may require proxy indicators of the population risk of vitamin D deficiency, such as the prevalence of rickets or metrics of usual UVB exposure. If a high prevalence of vitamin D deficiency is identified (>20% prevalence of 25(OH)D < 30 nmol/L) or the risk for vitamin D deficiency is determined to be high based on proxy indicators (e.g., prevalence of rickets >1%), food fortification and/or targeted vitamin D supplementation policies can be implemented to reduce the burden of vitamin D deficiency-related conditions in vulnerable populations.

Interactions between Vitamin D Status, Calcium Intake and Parathyroid Hormone Concentrations in Healthy White-Skinned Pregnant Women at Northern Latitude

Adverse effects of low vitamin D status and calcium intakes in pregnancy may be mediated through functional effects on the calcium metabolic system. Little explored in pregnancy, we aimed to examine the relative importance of serum 25-hydroxyvitamin D (25(OH)D) and calcium intake on parathyroid hormone (PTH) concentrations in healthy white-skinned pregnant women. This cross-sectional analysis included 142 participants (14 ± 2 weeks' gestation) at baseline of a vitamin D intervention trial at 51.9 °N. Serum 25(OH)D, PTH, and albumin-corrected calcium were quantified biochemically. Total vitamin D and calcium intakes (diet and supplements) were estimated using a validated food frequency questionnaire. The mean ± SD vitamin D intake was 10.7 ± 5.2 μg/day. With a mean ± SD serum 25(OH)D of 54.9 ± 22.6 nmol/L, 44% of women were <50 nmol/L and 13% <30 nmol/L. Calcium intakes (mean ± SD) were 1182 ± 488 mg/day and 23% of participants consumed <800 mg/day. The mean ± SD serum albumin-adjusted calcium was 2.2 ± 0.1 mmol/L and geometric mean (95% CI) PTH was 9.2 (8.4, 10.2) pg/mL. PTH was inversely correlated with serum 25(OH)D (r = -0.311, p < 0.001), but not with calcium intake or serum calcium (r = -0.087 and 0.057, respectively, both p > 0.05). Analysis of variance showed that while serum 25(OH)D (dichotomised at 50 nmol/L) had a significant effect on PTH (p = 0.025), calcium intake (<800, 800⁻1000, ≥1000 mg/day) had no effect (p = 0.822). There was no 25(OH)D-calcium intake interaction effect on PTH (p = 0.941). In this group of white-skinned women with largely sufficient calcium intakes, serum 25(OH)D was important for maintaining normal PTH concentration.

The roles of vitamin D and dietary calcium in nutritional rickets

The etiology and pathogenesis of nutritional rickets are becoming progressively clearer. Vitamin D deficiency has generally been considered the major or only player in the pathogenesis of nutritional rickets. However, recent research into calcium deficiency has now provided clinicians with reasons to investigate and manage patients with nutritional rickets more appropriately.

The important question when assessing cases of nutritional rickets is: “Is it calcium or vitamin D deficiency or both that play a major role in the pathogenesis of the disease?”

The case presentation in this review highlights the risk factors, clinical presentation and pathophysiology of nutritional rickets in a young South African black child from a semi-urban area in Johannesburg, a city with abundant sunshine throughout the year.

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Vitamin D and calcium deficiencies play synergistic roles in nutritional rickets.

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Dietary calcium intake of <300 mg/day increases the risk of nutritional rickets.

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Vitamin D status is worsened by dietary calcium deficiency itself.

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Marked elevation of 1,25-dihydroxyvitamin D is characteristic of calcium deficiency.

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Preventative strategies needed to decrease the prevalence of nutritional rickets.

Rickets

Rickets is a bone disease associated with abnormal serum calcium and phosphate levels. The clinical presentation is heterogeneous and depends on the age of onset and pathogenesis but includes bowing deformities of the legs, short stature and widening of joints. The disorder can be caused by nutritional deficiencies or genetic defects. Mutations in genes encoding proteins involved in vitamin D metabolism or action, fibroblast growth factor 23 (FGF23) production or degradation, renal phosphate handling or bone mineralization have been identified. The prevalence of nutritional rickets has substantially declined compared with the prevalence 200 years ago, but the condition has been re-emerging even in some well-resourced countries; prematurely born infants or breastfed infants who have dark skin types are particularly at risk. Diagnosis is usually established by medical history, physical examination, biochemical tests and radiography. Prevention is possible only for nutritional rickets and includes supplementation or food fortification with calcium and vitamin D either alone or in combination with sunlight exposure. Treatment of typical nutritional rickets includes calcium and/or vitamin D supplementation, although instances infrequently occur in which phosphate repletion may be necessary. Management of heritable types of rickets associated with defects in vitamin D metabolism or activation involves the administration of vitamin D metabolites. Oral phosphate supplementation is usually indicated for FGF23-independent phosphopenic rickets, whereas the conventional treatment of FGF23-dependent types of rickets includes a combination of phosphate and activated vitamin D; an anti-FGF23 antibody has shown promising results and is under further study.

CYP2R1 mutations causing vitamin D-deficiency rickets

CYP2R1 is the principal hepatic 25-hydroxylase responsible for the hydroxylation of parent vitamin D to 25-hydroxyvitamin D [25(OH)D]. Serum concentrations of 25(OH)D reflect vitamin D status, because 25(OH)D is the major circulating metabolite of vitamin D. The 1α-hydroxylation of 25(OH)D in the kidney by CYP27B1 generates the fully active vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25(OH)₂D). The human CYP2R1 gene, located at 11p15.2, has five exons, coding for an enzyme with 501 amino acids. In Cyp2r1-/- knockout mice, serum 25(OH)D levels were reduced by more than 50% compared wild-type mice. Genetic polymorphisms of CYP2R1 account for some of the individual variability of circulating 25(OH)D values in the population. We review the evidence that inactivating mutations in CYP2R1 can lead to a novel form of vitamin D-deficiency rickets resulting from impaired 25-hydroxylation of vitamin D. We sequenced the promoter, exons and intron-exon flanking regions of the CYP2R1 gene in members of 12 Nigerian families with rickets in more than one family member. We found missense mutations (L99P and K242N) in affected members of 2 of 12 families. The L99P mutation had previously been reported as a homozygous defect in an unrelated child of Nigerian origin with rickets. In silico analyses predicted impaired CYP2R1 folding or reduced interaction with substrate vitamin D by L99P and K242N mutations, respectively. In vitro studies of the mutant CYP2R1 proteins in HEK293 cells confirmed normal expression levels but completely absent or markedly reduced 25-hydroxylase activity by the L99P and K242N mutations, respectively. Heterozygous subjects had more moderate biochemical and clinical features of vitamin D deficiency than homozygous subjects. After an oral bolus dose of 50,000 IU of vitamin D₂ or vitamin D₃, heterozygous subjects had lower increases in serum 25(OH)D than control subjects, and homozygous subjects had minimal increases, supporting a semidominant inheritance of these mutations. No CYP2R1 mutations were found in 27 Nigerian children with sporadic rickets, a cohort of 50 unrelated Nigerian subjects, or in 628 unrelated subjects in the 1000 Genomes Project. We conclude that mutations in CYP2R1 are responsible for an atypical form of vitamin D-deficiency rickets, which has been classified as vitamin D dependent rickets type 1B (VDDR1B, MIM 600081).

Vitamin D deficiency causes rickets in an urban informal settlement in Kenya and is associated with malnutrition

The commonest cause of rickets worldwide is vitamin D deficiency, but studies from sub-Saharan Africa describe an endemic vitamin D-independent form that responds to dietary calcium enrichment. The extent to which calcium-deficiency rickets is the dominant form across sub-Saharan Africa and in other low-latitude areas is unknown. We aimed to characterise the clinical and biochemical features of young children with rickets in a densely populated urban informal settlement in Kenya. Because malnutrition may mask the clinical features of rickets, we also looked for biochemical indices of risk in children with varying degrees of acute malnutrition. Twenty one children with rickets, aged 3 to 24 months, were identified on the basis of clinical and radiologic features, along with 22 community controls, and 41 children with either severe or moderate acute malnutrition. Most children with rickets had wrist widening (100%) and rachitic rosary (90%), as opposed to lower limb features (19%). Developmental delay (52%), acute malnutrition (71%), and stunting (62%) were common. Compared to controls, there were no differences in calcium intake, but most (71%) had serum 25-hydroxyvitamin D levels below 30 nmol/L. These results suggest that rickets in young children in urban Kenya is usually driven by vitamin D deficiency, and vitamin D supplementation is likely to be required for full recovery. Wasting was associated with lower calcium (p = .001), phosphate (p < .001), 25-hydroxyvitamin D (p = .049), and 1,25-dihydroxyvitamin D (p = 0.022) levels, the clinical significance of which remain unclear.

Nutritional rickets around the world: an update

Worldwide, nutritional rickets continues to be an evolving problem with several causes. This paper provides an updated literature review characterising the prevalence, aetiology, pathophysiology and treatment of nutritional rickets worldwide. A systematic review of articles on nutritional rickets from various geographical regions was undertaken. For each region, key information was extracted, including prevalence, cause of rickets specific to the region, methods of confirming the diagnosis and current treatment and preventive measures. Calcium deficiency continues to be a major cause of rickets in Africa and Asia. Vitamin D deficiency rickets is perhaps increasing in the Americas, Europe and parts of the Middle East. There continues to be a distinct presentation of calcium-predominant versus vitamin D predominant rickets, although there are overlapping features. More careful diagnosis of rickets and reporting of 25-OHD concentrations has improved accurate knowledge of rickets prevalence and better delineated the cause. Nutritional rickets continues to be an evolving and multi-factorial problem worldwide. It is on a spectrum, ranging from isolated vitamin D deficiency to isolated calcium deficiency. Specific areas which require emphasis include a consistent community approach to screening and diagnosis, vitamin D supplementation of infants and at-risk children, prevention of maternal vitamin D deficiency and the provision of calcium in areas with low calcium diets.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Screening for nutritional rickets in a community

Concern has been expressed about the rising incidence of nutritional rickets with its associated long-term sequelae in children globally. In order to address the condition worldwide, it is imperative that accurate figures of its incidence are available particularly in at-risk communities. In order to obtain these figures, various screening tools and diagnostic criteria have been used with no standardization of methodologies, resulting in varying prevalences which may under- or over-estimate the prevalence depending of the techniques used. This review discusses the advantages and disadvantages of various screening tests used to diagnose rickets in communities. Clinical signs characteristic of rachitic deformities have been used extensively, but are likely to over-estimate the prevalence and are dependent on the clinical skills of the observer. Biochemical tests such as alkaline phosphatase and 25-hydroxyvitamin D have also been proposed. There is no consensus on the usefulness of alkaline phosphatase as a screening tool, while there is general agreement that the measurement of vitamin D status is unhelpful in screening for rickets. Finally, the confirmation of the presence of active rickets in suspected infants and children is dependent on radiographic findings, although these may be less helpful in adolescents whose growth plates might be closed or nearly so. In order to obtain uniformity in screening for rickets globally, the is a need for consensus among public health specialists, paediatric endocrinologists and those interested in paediatric bone disease as to the best methods to be employed to determine the prevalence of rickets, particularly in communities with limited resources.

Optimal Dose of Calcium for Treatment of Nutritional Rickets: A Randomized Controlled Trial

Calcium supplementation is indicated for the treatment of nutritional rickets. Our aim was to determine the optimal dose of calcium for treatment of children with rickets. Sixty-five Nigerian children with radiographically confirmed rickets were randomized to daily supplemental calcium intake of 500 mg (n = 21), 1000 mg (n = 23), or 2000 mg (n = 21). Venous blood, radiographs, and forearm areal bone density (aBMD) were obtained at baseline and at 8, 16, and 24 weeks after enrollment. The primary outcome was radiographic healing, using a 10-point radiographic severity score. The radiographic severity scores improved in all three groups, but the rate of radiographic healing (points per month) was significantly more rapid in the 1000-mg (-0.29; 95% confidence interval [CI] -0.13 to -0.45) and 2000-mg (-0.36; 95% CI -0.19 to -0.53) supplementation groups relative to the 500-mg group. The 2000-mg group did not heal more rapidly than the 1000-mg group. Of those who completed treatment for 24 weeks, 12 (67%), 20 (87%), and 14 (67%) in the 2000-mg, 1000-mg, and 500-mg groups, respectively, had achieved a radiographic score of 1.5 or less (p = 0.21). Serum alkaline phosphatase decreased and calcium increased similarly in all groups. Forearm diaphyseal aBMD improved significantly more rapidly in the 2000-mg group than in the 500-mg and 1000-mg groups (p < 0.001). Daily calcium intakes of 1000 mg or 2000 mg produced more rapid radiographic healing of rickets than 500 mg, but 2000 mg did not have greater benefit than 1000 mg. Some children require longer than 24 weeks for complete healing of nutritional rickets. © 2016 American Society for Bone and Mineral Research.