Vitamin D deficiency in Malaysian adolescents aged 13 years: findings from the Malaysian Health and Adolescents Longitudinal Research Team study (MyHeARTs)

Prevalence and risk factors of vitamin D deficiency among Afghan primary school children

Vitamin D deficiency is common in many societies and causes rickets and non-skeletal disorders in children. There are no published data on vitamin D deficiency in Afghanistan. We, therefore, investigated the prevalence and associated factors of vitamin D deficiency in Afghan school children in Kandahar City, Afghanistan. This cross-sectional analytical study was conducted from September 2022 to April 2023 in 510 primary school students aged 6-15 years from six randomly selected schools. Data were analyzed by using descriptive statistics, Chi-square test, and multivariate logistic regression. Of the 510 enrolled children, 54.3% were boys and 91.8% were poor. The mean serum 25(OH)D concentration was 9.3 ng/mL. Vitamin D deficiency (< 20 ng/mL) was detected in 436/510 (85.5%) children that was severe in 267/510 (52.4%). By logistic regression analysis, independent factors for vitamin D deficiency were: (i) older age group 11-15 vs. 6 - 10 years, adjusted odds ratio (AOR) 2.8 (95% confidence interval 1.2-6.2), (ii) poverty AOR 2.0 (1.0-4.3), (iii) not doing outdoor physical activity AOR 4.8 (2.8-8.1), and (iv) daily sunlight exposure < 60 min AOR 2.2 (1.3-3.7). Although Kandahar is very sunny throughout the year, vitamin D deficiency is highly prevalent among school boys and girls, placing them at great risk of vitamin D-deficient rickets. More work is needed to define the country-wide prevalence of vitamin D deficiency to inform robust strategies of vitamin D supplementation, the provision of vitamin D-fortified food to the school children in Kandahar City and health education programs that can be conducted with the help of international organizations.

Effectiveness of an e-Book on Bone Health as Educational Material for Adolescents: Single-Group Experimental Study

Background

Improved bone health during adolescence can have lifelong implications, reducing the risk of bone fragility.

Objective

This study aims to evaluate the effectiveness of an e-book in increasing knowledge about and promoting healthy practices related to bone health among Malay adolescents in Kuala Lumpur, Malaysia.

Methods

A total of 72 adolescents (female: n=51, 71%; age: mean 15, SD 0.74 y) were recruited from selected secondary schools. The participants answered a pretest web-based questionnaire on sociodemographic data, knowledge about osteoporosis, and physical activity. A video call was conducted to assess dietary calcium intake. Participants were provided with a link to an e-book on bone health and instructed to read it within 2 weeks. Postintervention assessments included those for knowledge, physical activity, dietary calcium intake, and acceptance of the e-book.

Results

There was a significant increase in the median knowledge score, which was 40.6% (IQR 31.3%-46.9%) during the pretest and 71.9% (IQR 53.9%-81.3%) during the posttest (P<.001). However, no changes were observed in dietary calcium intake or physical activity levels. Most participants did not meet the recommended calcium requirements (61/62, 98%) and exhibited sedentary behavior (pretest: 51/62, 82%; posttest: 48/62, 77%). The e-book, however, was well accepted, with the majority reporting that they understood the contents (70/72, 97%), liked the graphics (71/72, 99%), and approved of the layout (60/72, 83%) and font size (66/72, 92%) used.

Conclusions

The developed e-book effectively increases knowledge levels related to bone health and is well accepted among participants. However, this educational material did not improve bone health practices. Additional strategies are necessary to bridge the gap between knowledge and behavior change.

Vitamin D status and clinical implications in the adult population of Malaysia: a position paper by the Malaysian Vitamin D Special Interest Group

PURPOSE

Vitamin D deficiency and insufficiency is common among populations globally, and in Asia and Malaysia. The purpose of this Position Paper is to propose recommendations for both clinicians and non-clinicians to promote vitamin D sufficiency in Malaysian adults. Formation of a national multisector, multidisciplinary alliance is also proposed to progress initiatives relating to safe sun exposure, adequate vitamin D intake through food fortification, and vitamin D supplementation for high-risk groups.

METHODS

Literature reviews were undertaken to inform summaries of the following: vitamin D status globally and in Asian and Malaysian populations, vitamin D status among individuals with common medical conditions, and current recommendations to achieve vitamin D sufficiency through sun exposure, food intake and supplementation. Recommendations were based on the findings of the literature reviews, recent European guidance on vitamin D supplementation, the 2018 road map for action on vitamin D in low- and middle-income countries, and research recommendations proposed by the Malaysian Ministry of Health in 2017.

RESULTS

Recommendations on assessment of vitamin D in the adult Malaysian population include using serum or plasma 25-hydroxyvitamin D concentration as a biomarker, widespread participation by Malaysian laboratories in the Vitamin D Standardization Program, adoption of the US Endocrine Society definitions of vitamin D deficiency and insufficiency, and development of a comprehensive nationwide vitamin D status study. Specific high-risk groups are identified for vitamin D assessment and recommendations relating to loading doses and ongoing management are also made.

CONCLUSION

This Position Paper provides individual clinicians and national stakeholder organisations with clear recommendations to achieve vitamin D sufficiency in the adult population of Malaysia.

Prevalence and predictors of vitamin D deficiency among adults with epilepsy: A cross-sectional study

BACKGROUND

Vitamin D deficiency among adult people with epilepsy (PWE) is scarcely studied, despite its essential role in bone health and maintaining homeostasis. Several studies have studied the relationship between factors related to epilepsy and vitamin D metabolism. We aim to investigate this in our multi-ethnic society.

METHODS

This was a single-center cross-sectional study. We recruited 159 participants diagnosed with epilepsy on antiseizure medications (ASMs). We included those aged 18 years and above, excluding patients with long-term medical conditions that would affect vitamin D metabolism. Sociodemographic data and details of epilepsy were collated. Venous sampling was performed to analyze the levels of albumin-corrected calcium, phosphate, alkaline phosphatase, and 25-hydroxyvitamin D3 [25(OH)D]. Serum 25(OH)D level is defined as deficient (<20 ng/ml), insufficient (20-29 ng/ml), and sufficient (≥30 ng/ml).

RESULTS

The study reported that 73 (45.9%) participants had vitamin D deficiency, 38 (23.9%) had vitamin D insufficiency, and 48 (30.2%) patients had sufficient vitamin D levels. The predictors identified were PWE aged 18 to 44 years old (p = 0.001), female gender (OR 3.396, p = 0.002), and ethnicity (p < 0.001), specifically Malay and Chinese. However, no significant association was identified between types of ASMs, serum calcium, or the prevalence of vitamin D deficiency.

CONCLUSION

Vitamin D deficiency among PWE is prevalent in our local population, suggesting that regular screening should be considered for those at risk. Early identification would allow intervention to reduce the risk of future complications.

Vitamin D insufficiency is high in Malaysia: A systematic review and meta-analysis of studies on vitamin D status in Malaysia

PURPOSE

To estimate the vitamin D status of participants residing in Malaysia.

METHODS

PubMed, Scopus, Web of Science, and MyJurnal were searched up to June 2022 without language restrictions. Studies that reported the 25-hydroxyvitamin D [25(OH)D] concentrations and defined their cut-off for deficiency or insufficiency from healthy participants residing in Malaysia were included. The random effects model was used to pool vitamin D status using established cut-offs of <30, <50, and <75 nmol/L according to age group.

RESULTS

From 299 studies screened, 32 studies were included in the meta-analysis. The pooled proportion for <30 nmol/L was 21% (95% CI 9-36, n = 2,438 from 10 studies), while the pooled proportion <50 nmol/L was 64% (95% CI 56-72, n = 13,977 from 30 studies), and <75 nmol/L was 85% (95% CI 61-100, n = 1,376 from five studies). Heterogeneity was high (I2 ranged from 98-99%). Higher proportions of vitamin D insufficiency (defined as <50 nmol/L) were found in participants living in the urban areas (compared to rural areas), in females (compared to males), and in Malays and Malaysian Indians (compared to Malaysian Chinese) ethnicities.

CONCLUSION

More than half of Malaysians have insufficient vitamin D levels, despite being a country that is close to the equator. We strongly urge prompt public health measures to improve the vitamin D status in Malaysia.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42021260259].

Application of health belief model in the assessment of factors affecting exercise behaviours in preventing osteoporosis

Objectives

Osteoporosis is a skeletal disorder associated with weak and brittle bones, and more susceptible to fracture. Osteo-protective behaviours, such as exercise, may prevent osteoporosis. Therefore, this study aimed to assess the factors influencing the exercise behaviour in Malaysian adults and to assess their health beliefs and self-regulation in preventing osteoporosis.

Methods

A cross-sectional, self-administered questionnaire was conducted throughout Malaysia through a web-based or physical-based survey. The questionnaire consisted of three sections: demographic data, ten questions regarding social and family history related to osteoporosis and 38 questions with seven subdomains (i.e. susceptibility, seriousness, barriers, benefits, health motivation, self-efficacy and self-regulation) which measured the health belief scores and self-regulation using 5-point Likert scale. Descriptive, inferential analysis and linear regression were used to analyse the data.

Key findings

A total of 679 participants completed the questionnaire. The mean health belief score was 63.7%, which was moderate. Most participants (64.4%) perceived low susceptibility to osteoporosis [mean score = 47.0%, standard deviation (SD) = 16.2]. Participants with age 18–27 years (44.8%), single (45.0%) and monthly income &lt;RM 1000 (45.2%), perceived significant lower susceptibility to osteoporosis. Participants’ perception scores were high on the benefits of exercise (75.7%, SD = 16.4), health motivation (74.9%, SD = 17.1) and perceived low barriers to exercise (71.7%, SD = 14.9). Respondents who were at risk of osteoporosis and with family and friends diagnosed with osteoporosis obtained a higher score than those who did not.

Conclusions

The health belief score in the Malaysian population was moderate. However, the majority of participants were unaware of the susceptibility and seriousness of osteoporosis. Efforts need to be taken to break the barriers associated with exercise in preventing osteoporosis.

Vitamin D deficiency in South-East Asian children: a systematic review

OBJECTIVE

To describe the prevalence and determinants of vitamin D deficiency (VDD) among healthy children aged between 0 and 18 years living in South-East Asia (SEA).

DESIGN

We systematically searched Ovid MEDLINE and Ovid EMBASE for observational studies assessing VDD among healthy children in the SEA region as the primary or secondary outcome from database inception to 6 April 2021. PubMed was used for e-pubs and publications not indexed in Medline. Publications that included abstracts in English were included. We performed a systematic review to describe the prevalence of VDD in SEA children.

RESULTS

Our initial search identified 550 publications with an additional 2 publications from manual screening. Of those, 21 studies from 5 different countries (Thailand, Indonesia, Vietnam, Malaysia and Cambodia) were summarised and included in forest plots. The prevalence of VDD (<50 nmol/L) ranged from 0.9% to 96.4%, with >50% of newborns having VDD, and severe VDD (<30 nmol/L) ranged from 0% to 55.8%. Female sex and urban living were the most common determinants of VDD.

CONCLUSIONS

VDD among healthy children living in the SEA region is common. Efforts to detect VDD and the implementation of preventive measures, including education on safe sun exposure and oral vitamin D supplementation or food fortification, should be considered for key target groups, including adolescent females and pregnant and lactating women to improve the vitamin D status of newborns.

PROTOCOL REGISTRATION NUMBER

This study is registered with PROSPERO (CRD42020181600).

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.

Correlation between Levels of Vitamins D3 and E in Type 2 Diabetes Mellitus: A Case-Control Study in Serdang, Selangor, Malaysia

An overview of vitamins D3 and E suggests micronutrient deficiency contributes to type 2 diabetes mellitus (T2DM). A case-control study was conducted to determine the status of plasma vitamins D3 and E isomers amongst diabetic Malaysians. Two groups were recruited for participation, one comprising fifty diabetic subjects (DM) and one comprising fifty non-diabetic (non-DM) subjects, in order to assess their plasma vitamin D3, calcium and vitamin E status. Glycaemic status (haemoglobin A1c, HbA1c; fasting blood glucose, FBG; C-Peptide) and lipid profiles (total cholesterol, TC; triglycerides, TG; low-density lipoprotein-cholesterol, LDL-C; high-density lipoprotein-cholesterol, HDL-C) were assessed, followed by anthropometric measurements. The Mann-Whitney U-test, Kruskal-Wallis and Spearman's correlation coefficient were used to elucidate the association between levels of plasma vitamins D3 and E and T2DM. The vitamin D3 deficiency group (<20 ng/mL) showed a significant correlation (p < 0.05) with glycaemic status (HbA1c and FBG) and lipid profiles (HDL-C, LDL and TC). Spearman's correlation demonstrated that vitamin D3 status is strongly correlated with HDL levels (p < 0.05). Similarly, plasma total vitamin E levels >4.9 μg/mL revealed significantly different FBG, HbA1c, C-Peptide, LDL, HDL and TC levels across both groups. Moreover, family history, smoking, waist circumference and HbA1c levels demonstrated a significant association (p < 0.05) with levels of vitamins D and E but not FBG and lipid profiles. This could be because the pre-diabetic status among the non-DM group influenced the outcomes of this study.

Longitudinal Vitamin D Deficiency Among Malaysian Pregnant Women and Its Correlation With Neonatal Serum 25-Hydroxyvitamin D Levels

Objective: This study aimed to investigate the longitudinal relationship between maternal vitamin D concentrations during pregnancy and neonatal vitamin D concentrations at birth.

Materials and Methods: A prospective cohort of 236 healthy pregnant women from various ethnicity in early pregnancy (≤20 weeks of pregnancy) was followed at late pregnancy (28–40 weeks of pregnancy) and birth. Maternal serum 25-hydroxyvitamin D (25(OH)D) was assessed at early pregnancy (baseline) and late pregnancy, while neonatal cord serum 25(OH)D at birth. General estimating equations (GEE) were used to analyze the longitudinal association of maternal serum 25(OH)D levels during pregnancy and neonatal cord serum 25(OH)D levels at birth with adjusting for the time exposure, maternal weight gain, ethnicity, and skin type.

Results: The results showed that the prevalence of vitamin D deficiency (25(OH)D <50 nmol/L) was at 89.9, 92.2, and 96.1% in early, late pregnancy and in neonatal cord serum, respectively. The GEE analysis showed a trend that longitudinal vitamin D deficiency during pregnancy leads to lower vitamin D concentrations in neonatal cord blood (RR = 1.17; 95% CI (1.05–1.36); p = 0.04).

Conclusion: Longitudinal vitamin D deficiency during pregnancy leads to vitamin D deficiency in neonates at birth. A further trial is needed to affirm this association.

Is There a Benefit of Vitamin D Supplementation in Deficient Children and Adolescents Suffering from Obesity? A Meta-Analysis

This systematic review/meta-analysis aims to highlight the effect of vitamin D supplementation in deficient children suffering from obesity. Published clinical studies on vitamin D supplementation in obese children and adolescents with vitamin D deficiency were identified through a comprehensive MEDLINE/PubMed search (from July 1966 to November 2017). Outcomes intended after vitamin D supplementation were improvements in vitamin D status, BMI alterations and appetite changes. The inclusion criteria were children aged 2 to 18 years of both sexes in clinical trials that specified the oral and/or intramuscular dose of vitamin D supplementation. Ten studies were retrieved, but only 6 were relevant. First, supplemented obese children and adolescents were compared to non-obese controls; thereafter, supplemented obese children and adolescents were compared to matching obese peers given placebo. Pooled risks from the 2 studies that evaluated the number of obese and non-obese children and adolescents who improved upon vitamin D supplementation revealed that obesity poses a risk for not benefiting from the vitamin D supplementation regardless of the dose and the duration of supplementation. Pooled results from the 6 retrieved studies that compared supplemented obese children and adolescents to matching non-obese or obese peers given placebo revealed significantly lower vitamin D levels in obese participants than in non-obese peers. Vitamin D levels are significantly lower in obese children and adolescents with obesity, posing a risk for not benefiting from vitamin D supplementation regardless of the dose and duration of supplementation.

Vitamin D deficiency in children and adolescents with obesity: a meta-analysis

OBJECTIVE

To evaluate the prevalence of vitamin D deficiency in obese children and adolescents when compared to eutrophic controls.

METHODS

Systematic review with meta-analysis covering studies with patients aged 0-18 years old diagnosed with obesity and vitamin D deficiency and control group of eutrophic patients. The studies were retrieved in the PubMed, Embase, and LILACS databases in December 2019. The search used the terms "obesity" in combination with "pediatric population" and "vitamin D".

RESULTS

Through the search 3155 articles were retrieved; and after analysis, 20 studies were selected according to the study objectives. A total of 24,600 children and adolescents were included. Through meta-analysis, the relative risk for the association between obesity and vitamin D deficiency in the pediatric population was 1.41 (95% CI: 1.26-1.59) (I² = 89%, p < 0.01).

CONCLUSION

Children and adolescents with obesity have higher risk of vitamin D deficiency.

Developing a Model for Prediction of Serum 25-Hydroxyvitamin D Level: The Use of Linear Regression and Machine Learning Methods

OBJECTIVE

Because vitamin D status affects many organs and tissues of the body, it is important to determine the factors affecting it. The purpose of this study was to develop a model for predicting the serum 25-hydroxyvitamin D [25(OH)D] level in healthy young adults.

METHOD

This cross-sectional study was conducted on 201 healthy individuals aged 20 to 40 years old in Shiraz, Iran. Data regarding demographic characteristics, vitamin D intake through supplements, and sun exposure habits were gathered. Serum 25(OH)D concentration was also measured. Data were analyzed with R software using linear regression and different machine learning methods such as conditional tree, conditional forest and random forest.

RESULTS

Based on the linear regression, male sex (p < 0.001), taking 50,000 IU vitamin D₃ supplement monthly (p < 0.001), and lower waist circumference (p = 0.018) were identified as effective factors in increasing serum 25(OH)D levels. According to the conditional tree, taking 50,000 IU vitamin D₃ supplement monthly (p < 0.001) and sex (p < 0.001) were two main factors in the classification of individuals in terms of serum 25(OH)D levels. Besides, conditional forest and random forest results showed that the most important variable was taking 50,000 IU vitamin D₃ supplement monthly.

CONCLUSIONS

Supplement use is the first and most important predictor of 25(OH)D levels and other factors, including sex and waist circumference, are ranked thereafter, and the importance of these factors is greater in those who do not take vitamin D₃ supplements.

Obstructive sleep apnoea syndrome (OSAS) as a risk factor for secondary osteoporosis in children

Repetitive hypoxia seen in obstructive sleep apnoea syndrome (OSAS) may affect bone metabolism increasing the risk for secondary osteoporosis. This study investigates the association between OSAS in children and secondary osteoporosis. This cross-sectional study included 150 children aged 10–17 years: 86 with OSAS and 64 with no OSAS. OSAS was confirmed by polysomnography. Quantitative ultrasound (QUS) of calcaneum measuring speed of sound (SoS) and broadband ultrasound attenuation (BUA) were collected. Other parameters collected including bone profile, vitamin D levels, physical activity scoring and dietary calcium intake. Majority were male and Malay ethnicity. OSAS children were mostly obese (84%) and 57% had moderate to severe OSAS. Most had lower physical activities scores. Mean (SD) phosphate and Alkaline phosphatase were lower in OSA children compared to controls: PO₄, p = 0.039 and ALP, p < 0.001. Using both single and multivariate analysis, children with OSAS had a lower mean SoS value, p < 0.001 and p = 0.004 respectively after adjusting for age, BMI and bone profile. Children with OSAS had lower SoS suggesting risk for secondary osteoporosis. QUS calcaneus is a non-invasive, feasible tool and can be used to screen risk of osteoporosis in children. Further bone mineral density assessment is needed in these groups of children to confirm diagnosis of osteoporosis.

Vitamin D deficiency causing eosinophilic esophagogastroenteritis and ascites: a rare association

A 54-year-old Chinese man presented with ascites for 2 weeks. He had a preceding 2-year history of intermittent dysphagia, lethargy and general malaise. Blood investigations revealed leucocytosis with eosinophilia of 26.5%, whereas paracentesis showed turbid fluid with high protein content (45 g/L) and a high white blood cell count of 5580/µL, predominantly eosinophils (90%). An incidental assay of vitamin D showed a very low level of 13.5 ng/mL. No other cause of ascites was found. Gastroscopy was normal except for duodenitis. However, biopsies from lower oesophagus confirmed the presence of eosinophilic infiltration. Following vitamin D replacement, the patient experienced marked improvement in symptoms of dysphagia within 2 weeks and no recurrence of ascites after 3 months. The reason for the patient's vitamin D deficiency remains unclear. The marked improvement in the patient's health indicates a causative role of vitamin D deficiency in causing eosinophilic esophagogastroenteritis and associated eosinophilic ascites.

The longitudinal relationship between dietary intake, physical activity and muscle strength among adolescents

The longitudinal relationship between muscle strength, dietary intake and physical activity among adolescents is not well understood. We investigated the trend and longitudinal effects of dietary intakes and physical activity scores on muscle strength in adolescents. This prospective cohort study consisted of 436 adolescents (134 males; 302 females) aged 13 years at baseline (2012) who were followed up at the ages of 15 (2014) and 17 (2016) years, respectively. We measured muscle strength using a calibrated hand dynamometer, estimated dietary intake with a 7-d dietary history and physical activity scores with a validated physical activity questionnaire for older children. A generalised estimating equation was used to examine the effect of dietary intakes and physical activity on muscle strength changes. The analysis was performed separately by sex. The muscle strength for males and females had increased within the 5-year period. The dietary intakes (energy and macronutrients) also increased initially but plateaued after the age of 15 years for both sexes. Females recorded a significant declining trend in physical activity scores compared with males as they grew older. A significant positive longitudinal relationship was found between protein (β = 0·035; P = 0·016), carbohydrate intake (β = 0·002; P = 0·013) and muscle strength among males. However, no longitudinal relationship was found between dietary intake, physical activity and muscle strength among females. Higher protein and carbohydrate intake among males was associated with higher muscle strength but was not observed in females. Nutrition and physical activity focusing on strength building are required in early adolescence and need to be tailored to males and females accordingly.

Prevalence and Risk Factors for Hypovitaminosis D among Healthy Adolescents in Kota Bharu, Kelantan

OBJECTIVE

We aim to study the prevalence and risk factors of hypovitaminosis D among healthy adolescents in Kota Bharu, Kelantan based on the most recent Paediatric Consensus guideline.

METHODOLOGY

Ten public schools were selected from Kota Bharu, Kelantan. We analysed their demography (age, gender, ethnicity, income), measured their anthropometry (height, weight, BMI) and finally analysed their vitamin D and intactParathyroid hormone levels.

RESULTS

The prevalence of hypovitaminosis D was 16.9% among healthy teenagers with mean age of 15.9±1.39 years. Multivariate analysis showed female gender (adjusted OR, 95% CI): 23.7 (5.64, 100.3) and Chinese 0.24 (0.07, 0.84) were the significant predictors for hypovitaminosis D.

CONCLUSION

The prevalence of healthy adolescents with hypovitaminosis D in Kota Bharu, Kelantan was 16.9% using the most recent cut off value of 30 nmol/L from the global consensus 2016. Female and Malay were the significant risk factors associated with hypovitaminosis D. Higher cut off value would result in overestimation of prevalence rate of hypovitaminosis D.

The Relationship of Vitamin D Status, Adherence to the Mediterranean Diet, and Physical Activity in Obese Children and Adolescents

Vitamin D deficiency is associated with a range of chronic diseases, including childhood obesity. Prevalence of vitamin D deficiency in obese children and adolescents ranges from 6.5% to 57%. This cross-sectional study included 92 obese patients with body mass index z-score >2 and 39 subjects in the control group. Anthropometric and laboratory patient assessment were performed, including the fasting 25-hydroxyvitamin D (25(OH)D). Adherence to the Mediterranean diet was assessed by Mediterranean Diet Quality Index for children and adolescents (KIDMED index), while physical activity was evaluated by Physical Activity Questionnaire (PAQ). Serum levels of 25(OH)D were significantly lower in obese subjects compared to the control group (52.0 ± 17.93 vs. 64.09 ± 25.82 nmol/L, P = .003). The subgroup of obese patients with metabolic syndrome (MS) had significantly lower levels of serum vitamin D when compared to the subgroup of obese patients without MS and the control group (46.99 ± 17.11 vs. 54.58 ± 17.93 vs. 64.09 ± 25.82 nmol/L, P = .003). Obese patients with MS had lower PAQ score when compared to obese without MS and the control group (2.32 ± 0.55 vs. 2.49 ± 0.67 vs. 2.85 ± 0.63 nmol/L, P = .002), while no significant differences were observed in the KIDMED index (4.23 ± 1.81 vs. 4.21 ± 2.13 vs. 4.87 ± 2.29, P = .251), respectively. PAQ score was in positive correlation with serum levels of 25(OH)D (r = 0.305, P < .001). This study demonstrated that obese children and adolescents have significantly lower values of serum 25(OH)D. The positive correlation between vitamin D and PAQ score points to the importance of physical activity in the prevention of further cardiovascular complications and MS.

Risk of eczema, wheezing and respiratory tract infections in the first year of life: A systematic review of vitamin D concentrations during pregnancy and at birth

BACKGROUND

Allergic conditions and respiratory tract infections (RTIs) are common causes of morbidity and mortality in childhood. The relationship between vitamin D status in pregnancy (mothers), early life (infants) and health outcomes such as allergies and RTIs in infancy is unclear. To date, studies have shown conflicting results.

OBJECTIVE

This systematic review aims to gather and appraise existing evidence on the associations between serum vitamin D concentrations during pregnancy and at birth and the development of eczema, wheezing, and RTIs in infants.

DATA SOURCES

PubMed, MEDLINE, ProQuest, Scopus, CINAHL, Cochrane Library and Academic Search Premier databases were searched systematically using specified search terms and keywords.

STUDY SELECTION

Articles on the associations between serum vitamin D concentrations during pregnancy and at birth and eczema, wheezing, and RTIs among infants (1-year-old and younger) published up to 31 March 2019 were identified, screened and retrieved.

RESULTS

From the initial 2678 articles screened, ten met the inclusion criteria and were included in the final analysis. There were mixed and conflicting results with regards to the relationship between maternal and cord blood vitamin D concentrations and the three health outcomes-eczema, wheezing and RTIs-in infants.

CONCLUSION

Current findings revealed no robust and consistent associations between vitamin D status in early life and the risk of developing eczema, wheezing and RTIs in infants. PROSPERO registration no. CRD42018093039.

The Effects of Vitamin D Supplementation on Lipid and Inflammatory Profile of Healthy Adolescent Boys: A Randomized Controlled Trial

Background: Deficiency of vitamin D, an anti-inflammatory micronutrient with some favorable effects on lipid profiles, has been found to be highly prevalent in adolescents. We aimed to investigate the effect of a school-based vitamin D supplementation regimen on the correction of vitamin D deficiency as well as lipid and inflammatory profiles of healthy adolescent boys. Methods: In this randomized single-blind placebo-controlled trial, seventy-one healthy adolescent boys (age 17 years old) were recruited from one high school in Tehran, Iran, and randomly assigned to two groups. The supplement group received vitamin D pearls at a dose of 50,000 IU monthly for 6 months, this dose is indeed defined by the Ministry of Health in Iran for a potential national school-based vitamin D supplementation program. The other group was given placebo pearls for the same duration. Before and after the treatment, the serum levels of 25-hydroxy vitamin D (25(OH) D), parathyroid hormone (PTH), retinol, lead (Pb), the lipid profile and the inflammatory biomarkers were measured and compared. Results: Between-groups statistical analysis showed that a dose (50,000 IU/month) vitamin D significantly increased the serum levels of 25-hydroxyvitamin D (25 (OH) D) (p < 0.001) and decreased serum levels of PTH (p = 0.003). No significant change was observed in serum levels of retinol and Pb. Between-group analysis revealed that the serum levels of TG (P = 0.001) decreased while an increase in serum levels of HDL (p = 0.021) was observed (p < 0.05). Both the within- and between-group analysis showed that serum tumor necrosis factor receptor 2 (TNFR2) concentration declined while serum interleukin-10 (IL-10) increased in response to vitamin D supplementation (p < 0.05). Conclusion: A supplementation regimen of (50,000 IU/month) vitamin D in a context with high rates of vitamin deficiency has shown positive impacts on the serum vitamin D, lipid profile and inflammatory biomarkers in healthy adolescent boys.

Vitamin D deficiency and insufficiency in Malaysian children with spina bifida

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To determine the prevalence and potential risk factors of vitamin D deficiency and insufficiency among Malaysian children with spina bifida.

SETTING

Four Malaysian tertiary hospitals.

METHODS

Children with spina bifida were assessed for potential demographic, disease severity and lifestyle risk factors for vitamin D deficiency and insufficiency. Blood for 25-hydroxy vitamin D (25(OH)D) was taken. Vitamin D deficiency was defined as 25(OH)D levels ≤ 37.5 nmol/L and insufficiency as 37.6-50 nmol/L.

RESULTS

Eighty children aged 2-18 years (42 males) participated in the study. Vitamin D levels ranged from 14 to 105 nmol/L (mean 52.8, SD 19.1). Vitamin D deficiency was identified in 18 (22.5%) and insufficiency in 26 (32.5%) children. Logistic regression analysis showed that skin exposure to sunlight ≤ 21% body surface area (OR: 6.2, CI 1.7-22.9) and duration of sun exposure ≤ 35 min/day (OR: 4.0, CI 1.2-14.1) were significant risk factors for vitamin D deficiency and insufficiency, respectively.

CONCLUSIONS

Over half (55%) of Malaysian children with spina bifida seen in urban tertiary hospitals have vitamin D insufficiency and deficiency. Lifestyle sun exposure behaviours were risk factors for vitamin D deficiency and insufficiency.

Vitamin D non-sufficiency is prevalent in children with chronic liver disease in a tropical country

BACKGROUND

To determine vitamin D status in children with chronic liver disease (CLD) in a tropical country.

METHODS

Cross-sectional study in Malaysian children with CLD. Factors affecting serum vitamin D level (definition: deficient < 30 nmol/L; insufficient 30-50 nmol/L; sufficient ≥ 50 nmol/L) was analyzed.

RESULTS

Of the 59 children studied (males 32, 54%; median age 6.8 ± 5.3 years), the three most common causes were biliary atresia (n = 25), autoimmune hepatitis (n = 16) and sclerosing cholangitis (n = 6). The overall mean daily vitamin D intake was 715 ± 562 units/day. Thirteen (22%) patients had at least one clinical signs of rickets. Seventeen (29%) had serum bilirubin level ≥ 34 μmol/L. Eight (14%) children were deficient in vitamin D, eight (14%) were vitamin D-insufficient and 43 (73%) were sufficient. As compared with children with serum bilirubin <34 μmol/L, those with serum bilirubin ≥34 μmol/L were more likely to have rickets (24% vs. 65%; P < 0.002) and a lower serum vitamin D level (86.0 ± 54.9 nmol/L vs. 65.4 ± 48.2 nmol/L; P = 0.05) despite being given a significantly higher vitamin D dose (608 ± 571 vs. 970 ± 543 units/day; P = 0.008). The proportion of children with either deficient or insufficient vitamin D status was significantly higher in children with bilirubin level ≥34 μmol/L than in children <34 μmol/L (47% vs. 19%; P = 0.028).

CONCLUSION

Vitamin D deficiency and insufficiency is common in children with CLD in a tropical country. Regular monitoring of vitamin D status and screening for metabolic bone disease in all children with CLD is recommended. Higher dose of oral supplement or parenteral route should be considered, especially in those with bilirubin ≥34 μmol/L.

Effect of vitamin D supplementation on serum 25-hydroxyvitamin D concentration in children and adolescents: a systematic review and meta-analysis protocol

INTRODUCTION

The importance of vitamin D for bone health as well as its role in non-skeletal functions has long been documented. However, review investigations on the effect of vitamin D supplementation on serum 25-hydroxyvitamin D (25(OH)D) levels in children and adolescents are scarce. The aims of the current study were to assess the impact of various doses of vitamin D supplementation on serum 25(OH)D concentrations in children and adolescents, and to identify relevant determinants of variations in the effect of vitamin D supplementation.

METHODS

PubMed, Scopus, ISI Web of Science and Cochrane Central Register of Controlled Trials databases up to 27 September 2017 will systematically be searched for randomised controlled trials of vitamin D supplementation. We considered articles with the following control groups as eligible: placebo control, control group without any supplementation or a comparative arm investigation. Two reviewers will assess articles for eligibility according to prespecified selection criteria, after which data extraction and quality appraisal will be conducted by two independent reviewers. The quality assessment will be assessed using the Jadad scale. Meta-analyses will be conducted where appropriate. We will express continuous measures (ie, serum 25(OH)D concentration) as mean differences with 95% CIs. Heterogeneity of the data will be investigated via visual inspection of the forest plots and using χ² test on N-1 df, with a significance level of α=0.1. We will also assess individual study and subgroup characteristics and perform a sensitivity analysis. Publication bias will be assessed using funnel plot and statistical analysis of Egger's test.

ETHICS AND DISSEMINATION

Ethics approval is not required because the work will be carried out on published documents. The authors will publish findings from this review through peer-reviewed publication or conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42017067179.

Estimated vitamin D synthesis and dietary vitamin D intake among Asians in two distinct geographical locations (Kuala Lumpur, 3°N v. Aberdeen, 57°N) and climates

OBJECTIVE

To compare the contributions of UVB exposure and diet to total vitamin D among Asians living in Kuala Lumpur (KL) and Aberdeen (AB).

DESIGN

Longitudinal study.

SETTING

UVB exposure (using polysulfone film badges) and skin colour and dietary vitamin D intake (by web-based questionnaire) were measured at each season in AB and during south-west (SWM) and north-east monsoons (NEM) in KL.

SUBJECTS

One hundred and fifteen Asians in KL and eighty-five Asians in AB aged 20-50 years.

RESULTS

Median summer UVB exposure of Asians in AB (0·25 SED/d) was higher than UVB exposure for the KL participants (SWM=0·20 SED/d, P=0·02; NEM= 0·14 SED/d, P<0·01). UVB exposure was the major source of vitamin D in KL year-round (60%) but only during summer in AB (59%). Median dietary vitamin D intake was higher in AB (3·50 µg/d (140 IU/d)), year-round, than in KL (SWM=2·05 µg/d (82 IU/d); NEM=1·83 µg/d (73 IU/d), P<0·01). Median total vitamin D (UVB plus diet) was higher in AB only during summer (8·45 µg/d (338 IU/d)) compared with KL (SWM=6·03 µg/d (241 IU/d), P=0·04; NEM=5·35 µg/d (214 IU/d), P<0·01), with a comparable intake across the full year (AB=5·75 µg/d (230 IU/d); KL=6·15 µg/d (246 IU/d), P=0·78).

CONCLUSIONS

UVB exposure among Asians in their home country is low. For Asians residing at the northerly latitude of Scotland, acquiring vitamin D needs from UVB exposure alone (except in summer) may be challenging due to low ambient UVB in AB (available only from April to October).

Risk factors of vitamin D deficiency among 15-year-old adolescents participating in the Malaysian Health and Adolescents Longitudinal Research Team Study (MyHeARTs)

Background

This study is to determine the prevalence and risk factors of vitamin D deficiency (vitamin D ≤ 50 nmol/L) among 15-year-old Malaysian adolescents. By identifying potential risk factors, prevention strategies and interventions can be carried out to improve the vitamin D status in adolescents.

Methods and findings

Stratified random sampling design was used to select adolescents from 15 urban and rural secondary schools in Selangor, Perak and Kuala Lumpur, Malaysia. Data collection was carried out from 1^st April 2014 to 30^th June 2014. Information regarding socio-demographic characteristics, sun exposure and sun protective behaviours, clinical data and environmental factors were collected. Blood for total vitamin D was sampled. Descriptive and multivariate logistic regressions were performed. Total 1061 participants were analyzed (62% were female; mean age 15.1 ± 0.4 years). The prevalence of vitamin D deficiency was 33%. Mean vitamin D was lower in female (53 ± 15 nmol), obese (body fat percentage (≥25%^m; ≥33.8%^f) (56 ± 16 nmol/L), Malays (58 ± 18 nmol/L) and Indians (58 ± 15 nmol/L). In multivariate analysis, female (OR = 5.5; 95% CI: 3.4–7.5), Malay (OR = 3.2; 95% CI: 1.3–8.0), Indian (OR = 4.3; 95% CI: 1.6–12.0) and those always wearing long sleeve (OR = 2.4; 95% CI: 1.1–5.4) were more likely to have vitamin D deficiency. For female participants, ethnicity {Malays (OR = 6.7; 95% CI: 2.0–18.5), Indian (OR = 4.5; 95% CI: 1.8–19.3)} was an important risk factors. Cloud cover, school residence, skin pigmentation, sun-exposure and sun-protective behaviours were not significant risk factors. The limitation of this study was recall bias as it relied on self-reported on the sun exposure and protective behaviours. The diet factors were not included in this analysis.

Conclusions

The prevalence of Vitamin D deficiency among Malaysian adolescents was considerable. Gender, ethnicity and clothing style were important risk factors.

Dietary Acid Load, IGF-1 Single Nucleotide Polymorphism and Bone Resorption among Postmenopausal Chinese Women

The interaction of dietary and genetic factors may affect the development of bone deterioration. This study investigated whether the effects of dietary acid load (DAL) on bone loss in postmenopausal Chinese women were moderated by the insulin-like growth factor-1 (IGF-1) single nucleotide polymorphism, a known gene that plays a role in the regulation of bone formation and bone remodeling. A total of 217 healthy participants were recruited from the National Council of Senior Citizens Organizations Malaysia. Serum collagen type 1 cross-linked C-telopeptide was used as a surrogate bone marker to assess bone resorption and Agena^® MassARRAY genotyping analysis was used to identify the signaling of IGF-1 rs35767. The dietary acid load was measured by potential renal acid load score while physical activity was ascertained using the Global Physical Activity Questionnaire. Hierarchical regression was applied to test the main and interaction effects of DAL and IGF-1 genotypes in bone resorption. The result supported the diet-dependent acid-base balance theory that higher DAL was positively associated with bone resorption (β = 0.152, p = 0.031, F_(6,207) = 2.11, sig-F = 0.036, R² = 0.079). However, the results indicated that there was no significant correlation between IGF-1 and bone resorption, or any significant interaction between DAL and IGF-1. In conclusion, there was no moderating effect of IGF-1 on the relationship between DAL and bone resorption.

Current Evidence on Vitamin D Deficiency and Metabolic Syndrome in Obese Children: What Does the Evidence from Saudi Arabia Tell Us?

Obesity and vitamin D deficiency represent major health problems among Saudi children, and have been linked to chronic diseases. Obese children are at risk of developing vitamin D deficiency, which appears to have negative influences on energy homeostasis, impeded bone mineralisation, insulin resistance and inflammation. Evidence supporting the association between vitamin D deficiency of obese children and metabolic syndrome has not specifically been studied in early childhood. The mechanisms through which vitamin D deficiency is associated with metabolic syndrome in obese children needs further elucidation. This commentary aims to (i) summarise current knowledge of the association between vitamin D deficiency and metabolic syndrome in obese children; and (ii) discuss current evidence for the association among Saudi Arabian children.

The associations between VDR BsmI polymorphisms and risk of vitamin D deficiency, obesity and insulin resistance in adolescents residing in a tropical country

Background

The vitamin D receptor (VDR) gene is expressed abundantly in different tissues; including adipocytes and pancreatic beta cells. The rs1544410 or BsmI single nucleotide polymorphism (SNP) in the intronic region of the VDR gene has been previously associated with vitamin D levels, obesity and insulin resistance.

Aims

This study was aimed to examine the association between BsmI polymorphism and risk of vitamin D deficiency, obesity and insulin resistance in adolescents living in a tropical country.

Methods

Thirteen-year-old adolescents were recruited via multistage sampling from twenty-three randomly selected schools across the city of Kuala Lumpur, Malaysia (n = 941). Anthropometric measurements were obtained. Obesity was defined as body mass index higher than the 95^th percentile of the WHO chart. Levels of fasting serum vitamin D (25-hydroxyvitamin D (25(OH)D)), glucose and insulin were measured. HOMA-IR was calculated as an indicator for insulin resistance. Genotyping was performed using the Sequenom MassARRAY platform (n = 807). The associations between BsmI and vitamin D, anthropometric parameters and HOMA-IR were examined using analysis of covariance and logistic regression.

Result

Those with AA genotype of BsmI had significantly lower levels of 25(OH)D (p = 0.001) compared to other genotypes. No significant differences was found across genotypes for obesity parameters. The AA genotype was associated with higher risk of vitamin D deficiency (p = 0.03) and insulin resistance (p = 0.03) compared to GG. The A allele was significantly associated with increased risk of vitamin D deficiency compared to G allele (adjusted odds ratio (OR) = 1.63 (95% Confidence Interval (CI) 1.03–2.59, p = 0.04). In those with concurrent vitamin D deficiency, having an A allele significantly increased their risk of having insulin resistance compared to G allele (adjusted OR = 2.66 (95% CI 1.36–5.19, p = 0.004).

Conclusion

VDR BsmI polymorphism was significantly associated with vitamin D deficiency and insulin resistance, but not with obesity in this population.