Vitamin D status and its determinants during autumn in children at northern latitudes: a cross-sectional analysis from the optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study

Demographic and disease-related factors impact bone turnover and vitamin D in children with hemato-oncological diseases

Children with hemato-oncological diseases may have significant skeletal morbidity, not only during and after treatment but also at the time of diagnosis before cancer treatment. This study was designed to evaluate the vitamin D status and circulating bone metabolic markers and their determinants in children at the time of diagnostic evaluation for hemato-oncological disease. This cross-sectional study included 165 children (91 males, median age 6.9 yr range 0.2-17.7 yr). Of them, 76 patients were diagnosed with extracranial or intracranial solid tumors, 83 with leukemia, and 6 with bone marrow failure. Bone metabolism was assessed by measuring serum 25OHD, PTH, bone alkaline phosphatase, intact N-terminal propeptide of type I procollagen, and C-terminal cross-linked telopeptide of type I collagen. Vitamin D deficiency was found in 30.9% of children. Lower 25OHD levels were associated with older age, lack of vitamin D supplementation, season outside summer, and a country of parental origin located between latitudes -45° and 45°. Children diagnosed with leukemia had lower levels of markers of bone formation and bone resorption than those who had solid tumors or bone marrow failure. In conclusion, vitamin D deficiency was observed in one-third of children with newly diagnosed cancer. Bone turnover markers were decreased in children with leukemia, possibly because of the suppression of osteoblasts and osteoclasts by leukemic cells. The identification of patients with suboptimal vitamin D status and compromised bone remodeling at cancer diagnosis may aid in the development of supportive treatment to reduce the adverse effects of cancer and its treatment.

Vitamin D level and bone profile among 1- to 5-year-old children in Galle municipality and Bope-Poddala areas in Sri Lanka

Objective

Identify the incidence and risk factors of vitamin D deficiency/vitamin D insufficiency in children aged 1-5 years.

Methods

A cross-sectional survey was conducted among children between the ages of 1 and 5 in the Bope-Poddala and Galle municipality areas. The sample was obtained by cluster sampling method. Data on socio-demography, pregnancy, sun exposure, and diet were obtained. Serum 25(OH)D concentrations were measured and the cutoff value was determined as per the global consensus in 2016.

Results

Among 100 children, the mean serum 25(OH)D level was 86.4 nmol/L (24.06 ng/mL). The prevalence of vitamin D deficiency and vitamin D insufficiency was 7% and 28%, respectively. Birth weight and sunlight exposure were significantly different among vitamin D deficiency/vitamin D insufficiency and sufficient groups. Both were found to be risk factors for vitamin D deficiency/vitamin D insufficiency in logistic regression.

Conclusion

Vitamin D deficiency/vitamin D insufficiency is significant among children aged 1-5 years and decreased sun exposure and low birth weight are the main risk factors.

Metal Load of Potentially Toxic Elements in Tuna (Thunnus albacares)-Food Safety Aspects

The consumption of marine fishes has a positive effect on a consumer's health; however, it poses a potential risk due to their level of heavy metals in their body. Heavy metals can be naturally found in the environment, but their concentration can be increased with anthropogenic activities. Samples of tuna (Thunnus albacares) were collected at a fishery market. The potentially toxic elements (arsenic, cadmium, lead, and mercury) were determined with a validated method in the flesh of fish using inductively plasma optical emission spectrometry after microwave digestion. Generally, the average concentration of them was below the official limit values regulated by the European Union, except for lead. Based on the concentrations of arsenic (inorganic derivates: 0.05 ± 0.02 mg/kg) and cadmium (0.03 ± 0.01 mg/kg) in the tuna fish samples, and their calculated EDI values (As: 0.03-0.09 µg/kg/day; Cd: 0.05-0.07 µg/kg/day), the investigated food could be declared safe for human consumption. Generally, mercury content was below the official regulated limit, and the calculated EDI value was below the dietary reference value (0.3 μg/kg/day) in most of the samples (90%), exceeding it only in two samples (0.69 and 0.82 μg/kg/day); thus, they may not be harmful to the consumer. The concentration of lead above the official maximum limit (0.30 mg/kg) in 40% of tuna samples (0.30-1.59 mg/kg), as well as the exceeding of the dietary reference value for lead (adult: 0.16 μg/kg/day; children: 0.26 μg/kg/day) based on the calculated EDI values (0.28-1.49 μg/kg/day), draw attention to the importance of environmental pollution and the protection of consumers' health.

Vitamin D Determinants, Status, and Antioxidant/Anti-inflammatory-Related Effects in Cardiovascular Risk and Disease: Not the Last Word in the Controversy

Beyond its key role in calcium homeostasis, vitamin D has been found to significantly affect the cardiovascular (CV) system. In fact, low vitamin D levels have been associated with increased CV risk, as well as increased CV morbidity and mortality. The majority of effects of this molecule are related directly or indirectly to its antioxidative and anti-inflammatory properties. Generally, vitamin D insufficiency is considered for 25-hydroxyvitamin D (25(OH)D) levels between 21-29 ng/mL (corresponding to 52.5-72.5 nmol/L), deficiency as 25(OH)D levels less than 20 ng/mL (<50 nmol/L), and extreme deficiency as 25(OH)D less than 10 ng/mL (<25 nmol/L). However, the definition of an optimal vitamin D status, as defined by 25(OH)D, remains controversial for many extra-bone conditions, including CV disease. In this review, confounding factors affecting the 25(OH)D measurement and status will be discussed. In particular, available evidence on the mechanism and role of vitamin D in relation to CV risk and disease through its antioxidant effect will be reported, also facing the aspect regarding the debate on the minimum blood 25(OH)D level required to ensure optimal CV health.

Vitamin D status of 3-year-old children in Denmark: determinants and associations with bone mineralisation and blood lipids

PURPOSE

Low vitamin D status is a global problem and has been associated with reduced skeletal and cardiometabolic health. However, evidence in young children is lacking. We, therefore, aimed to characterise vitamin D status in toddlers, identify its determinants, and explore if vitamin D status was associated with bone mineralisation and lipid profile.

METHODS

We used cross-sectional data from 3-year-old children (n = 323) living in Denmark (latitude: 55°N). Bone mineralisation (n = 108) was measured by DXA. Blood samples were analysed for serum 25-hydroxyvitamin D (s-25(OH)D) by LC-MS/MS, triacylglycerol, and total, low- and high density lipoprotein cholesterol.

RESULTS

Mean ± SD s-25(OH)D was 69 ± 23 nmol/L, but varied with season. During winter, 38% had inadequate s-25(OH)D (< 50 nmol), whereof 15% had deficiency (< 30 nmol/L); these numbers were only 7 and 1% during summer. In terms of status determinants, supplement use (66% were users) was associated with s-25(OH)D (P < 0.001), whereas dietary vitamin D intake (median [25-75^th percentile] of 1.3 [0.9-1.9] µg/d), sex, parental education, BMI, and physical activity were not. There were no associations between s-25(OH)D and blood lipids or bone measurements, using either unadjusted or adjusted regression models.

CONCLUSION

More than 1/3 of Danish toddlers had inadequate vitamin D intake during winter, but acceptable mean vitamin D status. In addition to season, supplement use was the main determinant of vitamin D status, which was, however, not associated with bone mineralisation or lipid profile. The results support recommendations of vitamin D supplements during winter at northern latitudes, but potential health effects need further investigation.

Vitamin D status in healthy Italian school-age children: a single-center cross-sectional study

BACKGROUND

Vitamin D is involved in calcium homeostasis and bone metabolism, although its extra-skeletal actions are also well-known. Low serum 25(OH)D levels are common both in adults and children worldwide.

METHODS

The purpose of this cross-sectional study was to determine the distribution of 25(OH)D levels in a cohort of healthy Italian school-age children, aged 5-10 years, in relationship to determinants of vitamin D deficiency such as season, BMI, gender, age and ethnicity.

RESULTS

The mean serum 25(OH) D level was 28.2 ng/mL; the prevalence of 25(OH)D sufficiency (> 30 ng/mL), insufficiency (20-30 ng/mL), deficiency (10-20 ng/mL) and severe deficiency (< 10 ng/mL) was 36%, 37%, 21% and 6% of the study-group population, respectively. The lower serum 25(OH)D values were observed during winter (21.6 ng/mL) and spring (22.9 ng/mL), as compared to summer (46.7 ng/mL) (p < 0.001). Higher BMI z-scores were associated with lower 25(OH)D level while no statistical difference was observed as related to gender and age groups.

CONCLUSIONS

Healthy Italian schoolchildren show low 25(OH)D levels, particularly during winter and spring time. Seasonality, ethnicity and overweight/obesity were confirmed to influence the vitamin D status, thus indicating the need for effective initiatives to support adequate vitamin D status in this population group.

Sources of vitamin D and determinants of serum 25-hydroxyvitamin D in Finnish adolescents

PURPOSE

To study the intake and sources of vitamin D and determinants of serum 25-hydroxyvitamin D (S-25(OH)D) in Finnish adolescents.

METHODS

We studied 265 adolescents (117 girls) aged 15-17 years attending 8-year examinations of the PANIC Study, assessed diet using food records and other lifestyle factors by questionnaires, and analyzed S-25(OH)D by chemiluminescence immunoassay and determinants of S-25(OH)D using multivariate linear regression.

RESULTS

Mean (standard deviation) of total vitamin D intake from food and supplements was 19.2 (13.1) µg/d, and that of dietary vitamin D intake was 9.9 (5.4) µg/d. Milk fortified with vitamin D was the main dietary source of vitamin D, providing 45% of daily intake. Altogether, 29% of the adolescents used no vitamin D supplements and 25% did not meet the recommended total vitamin D intake of 10 µg/d. Mean (standard deviation) of S-25(OH)D was 62.0 (18.8) nmol/l, and S-25(OH)D was < 50 nmol/l in 29.5% of the adolescents. Vitamin D intake from supplements was the main determinant of S-25(OH)D (β = 0.465, p < 0.001), followed by consumption of milk products (β = 0.251, p < 0.001), consumption of meat products (β = 0.179, p = 0.002), travels to sunny countries (β = 0.178, p = 0.002), and average daylight time (β = 0.162, p = 0.004).

CONCLUSION

Most of the adolescents had vitamin D intake at the recommended level, although a fourth did not meet the recommended total vitamin D intake of 10 µg/d and almost a third had S-25(OH)D < 50 nmol/l. More attention should be paid to the sufficient intake of vitamin D in adolescents who do not use vitamin D supplements or fortified milk products.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01803776, registered March 3, 2013.

Vitamin D Status and Health Outcomes in School Children in Northern Ireland: Year One Results from the D-VinCHI Study

(1) Background: Vitamin D status has never been investigated in children in Northern Ireland (UK). (2) Methods: Children (4-11 years) (n = 47) were recruited from November 2019 to March 2020 onto the cross-sectional study. Anthropometry was assessed. Plasma 25-hydroxyvitamin D (25(OH)D) was analysed. Vitamin D intake, parental knowledge and perceptions, participant habits, physical activity and sedentary behaviour were established via questionnaire. Muscle strength was assessed via isometric grip strength dynamometry and balance via dominant single-leg and tandem stance. Parathyroid hormone, bone turnover markers (OC, CTX and P1NP), glycated haemoglobin and inflammatory markers (CRP, IFN-γ, IL-10, IL-12p70, IL-13, IL-1β, IL-2, IL-4, IL-6, IL-8 and TNF-α) were analysed. (3) Results: Mean (SD) 25(OH)D was 49.17 (17.04) nmol/L (n = 47); 44.7% of the children were vitamin D sufficient (25(OH)D >50 nmol/L), 48.9% were insufficient (25-50 nmol/L) and 6.4% were deficient (<25 nmol/L). 25(OH)D was positively correlated with vitamin D intake (µg/day) (p = 0.012, r = 0.374), spring/summer outdoor hours (p = 0.006, r = 0.402) and dominant grip strength (kg) (p = 0.044, r = 0.317). Vitamin D sufficient participants had higher dietary vitamin D intake (µg/day) (p = 0.021), supplement intake (µg/day) (p = 0.028) and spring/summer outdoor hours (p = 0.015). (4) Conclusion: Over half of the children were vitamin D deficient or insufficient. Wintertime supplementation, the consumption of vitamin D rich foods and spring/summer outdoor activities should be encouraged to minimise the risk of vitamin D inadequacy.

Relationship between vitamin D and physical activity: systematic review and meta-analysis

Abstract Vitamin D plays an important role in immune function and inflammation and the physical activity demonstrate relationship near to syntheses of vitamin D, considering to necessary to factors immunologics, environmental and physical. We searched five databases through February 20, 2021. Two reviewers screened the studies, collected data, assessed the risk of bias, and ranked the evidence for each outcome across the studies, independently and in duplicate. The prespecified endpoints of interest were Cardiorespiratory Fitness; Sunlight Exposure; Body Mass Index (BMI). We only included data from peer-reviewed articles in our primary analyses. In our primary analysis, there was a positive trend between serum 25(OH)D <20 ng/ml and body mass index, this result should be interpreted with caution, considering confidence intervals (RR 1.10 95% CI 0.37 to 1.83. We identified 4 high quality evidence that vitamin D levels and high physical activity required a direct relationship considering (four trials with 2,253) ; RR 0. (RR 0.0; 95% CI -0.15 to 0.15) (RR 0.59; 95% CI 0.43 to 0.75. Although the evidence available so far, from observational studies of medium quality, can be seen as showing a trend towards an association between sufficient serum levels of 25(OH)D and physical activity, this relationship has been shown. have a stimulating effect on vitamin D synthesis, the relationship of low body mass index with sufficient vitamin D levels is not based on solid evidence. We await results from ongoing studies to determine this effectiveness.

Incidence rate of vitamin D deficiency and FGF23 levels in 12- to 13-year-old adolescents in Japan

INTRODUCTION

The incidence rate of vitamin D deficiency is increasing throughout the world. We measured the incidence rate of vitamin D deficiency and fibroblast growth factor 23 (FGF23) levels in 12- to 13-year-old adolescents in Japan.

MATERIALS AND METHODS

A total of 492 adolescents (247 boys and 245 girls) from Japanese community enrolled in this study. 25 hydroxyvitamin D (25(OH)D) was measured with radioimmunoassay. In the subjects with low 25(OH)D levels (≦ 20 ng/ml), intact parathyroid hormone (iPTH), calcium (Ca), phosphorus (P), albumin (Alb), alkaline phosphatase (ALP) and FGF23 were measured.

RESULTS

25(OH)D levels were significantly lower in girls (20.9 ± 3.1 ng/ml) than in boys (22.2 ± 3.3 ng/ml) (p < 0.0001). Fifty-five boys (22.3%) and 83 (33.9%) girls showed vitamin D deficiency (< 20 ng/ml). One-hundred eighty-six (75.3%) boys and 162 (66.1%) girls showed vitamin D insufficiency (≧ 20 ng/ml, < 30 ng/ml). In the subjects whose 25(OH)D levels were ≦ 20 ng/ml, the levels of iPTH, Ca, P, Alb, ALP and FGF23 were 22.3 ± 9.0 pg/ml, 9.5 ± 0.4 mg/dl, 4.7 ± 0.6 mg/dl, 4.6 ± 0.3 g/dl, 920.8 ± 339.3 U/l and 42.6 ± 26.0 pg/ml, respectively. There was a significant negative association between serum 25(OH)D levels and iPTH [r =  - 0.290 (p < 0.0001)]. There was no significant association between serum 25(OH)D levels and FGF23.

CONCLUSION

We show that 28% of Japanese 12- to 13-year-old early adolescents suffer from vitamin D deficiency. Findings from this study indicate that vitamin D deficiency requires close oversight in public health during adolescence to ensure proper bone health.

Vitamin D status and its dietary and lifestyle factors in children during the first 5 years of life: A cross-sectional multicentre Jiangsu bone study

BACKGROUND

To explore the vitamin D status with its demographic and lifestyle factors including dietary, supplementation, and physical activity in 0-5 years old children.

METHODS

This was a large population-based cross-sectional multicentre study in which the children were recruited from 12 Children's Health Care Centers by a stratified cluster random-sampling method in 10 cities in Jiangsu Province, China.

RESULTS

A total number of 5289 children were investigated. The prevalence of vitamin D deficiency was 30.1%. The concentration of 25 hydroxyvitamin D was 64.0 (46.3-83.0) nmol mL^-1 after adjustment for covariates. Children with higher risk of vitamin D deficiency were more likely to be at older age, girls, survey conducted in spring, location in southern Jiangsu province, residence in urban, outdoor activity < 2 h day^-1 (all p < 0.05). Moreover, those with lower risk were more likely to be the number of parity ≥ 2 times, vitamin D supplementation from birth to 6 months, the initial time of vitamin D supplementation after birth ≤ 1 months, vitamin D and calcium supplementation in the last 3 months, and dose of vitamin D supplementation > 400 IU day^-1 (all p < 0.05). Children with preferences for sweets, meat consumption > 150.0 g day^-1 , milk consumption < 250 mL day^-1 , time of sleeping < 10 h day^-1 had higher risks of vitamin D deficiency. However, these relationships were affected by demographics.

CONCLUSIONS

Vitamin D status during the first five years of life was suboptimal and was associated with demographic and lifestyle determinants including milk, meat, sweets, vitamin D and calcium supplementation, sleeping and outdoor activity.

Potential health-related behaviors for pre-school and school-aged children during COVID-19 lockdown: A narrative review

As a consequence of the COVID-19 pandemic, different measures have been implemented by governments from each affected country. Such measures usually involve restrictions on the movement of citizens, and have had a profound effect on usual activities and timetables. As a result of school closures and strict restrictions regarding going outside home, children have been one of the most disadvantaged population groups during the lockdown period. We therefore aimed to investigate potential health risk behaviors amongst isolated pre-school and school-aged children. We retrieved relevant articles from MEDLINE, Web of Science, PsycInfo, and Scopus databases to describe identified health-related behaviors (i.e. screen exposure, environmental influence, physical activity and fitness, sedentariness, sleep patterns, eating habits, psychological response, body composition, and injuries) in relation to social isolation and social deprivation of children without previous illness or conditions. This review depicts the potential health-related behaviors according to related literature, and put the focus on future short and long-term sequels of social isolation. Socio-affective complications and insufficient physical activity are underscored as two of the main concerns, particularly among socio-economic deprived children. Both issues could be effectively addressed with either adequate parental or community guidance.

Play with Your Food and Cook It! Tactile Play with Fish as a Way of Promoting Acceptance of Fish in 11- to 13-Year-Old Children in a School Setting-A Qualitative Study

Despite a tradition of consuming fish in Denmark and despite the health benefits of eating fish, Danish children consume only one-third of the officially recommended amount of fish. The objective of this study was to explore an experiential and sensory-based exercise in a school setting with focus on tactile play and cooking as a way of promoting 11- to 13-year-old children’s acceptance of fish. The design was a qualitative exploratory multiple-case design using participant observation in a school setting. Six classes were recruited from the Eastern part of Denmark (n = 132). Based on an exercise with cooking fish and gyotaku (fish print), four meta-themes were identified by applying applied thematic analysis: rejection, acceptance, craftsmanship, and interaction. Rejection and acceptance appeared along a rejection–acceptance continuum related to how the fish was categorised (animal, non-animal, food) in different phases of the experiment. Rejection was promoted by mucus, smell, animalness, and texture, whereas helping each other, tactile play, and craftsmanship promoted acceptance. In conclusion, this study found that tactile play combined with cooking could be a way of promoting acceptance of fish. The findings also support a school setting as a potential gateway in promoting healthy food behaviour.

Associations of physical activity with vitamin D status depends on obesity status in old adults

PURPOSE

Obesity has been associated with low 25-hydroxy-vitamin D (25OHD). The causes of hypovitaminosis D in obese individuals are not known. The present work aimed to investigate 25OHD in obese and normal-/overweight subjects with consideration of leisure-time physical activity (LTPA).

METHODS

Community-dwelling old adults (N = 229, 73.7 ± 5.7yrs, 58.2% female) from the Reykjavik capital area in Iceland participated in this cross-sectional study. LTPA, vitamin D intake, body composition and background variables were assessed. 25OHD was measured in fasting blood samples.

RESULTS

Mean LTPA was 5.7 ± 5.6 h/week and the common activities were walking and gardening. Mean 25OHD was 66.7 ± 28.1 nmol/L and 8.5/21.2% were below 30 and 50 nmol/L, respectively. Obese participants (n = 84) had lower 25OHD (-11.0 ± 3.8 nmol/L,P < 0.001) and lower LTPA (-2.5 + 0.8 h/week,P = 0.001) than normal-/overweight subjects (n = 145). Linear models showed that LTPA (h/week) was associated with higher 25OHD in normal-/overweight participants only (1.3 nmol/L, P < 0.001) but not in obese (-0.7 nmol, P = 0.245). Fish oil intake was associated with higher 25OHD both in normal-/overweight (19.2 ± 4.5 nmol/L, P = 0.001) and obese subjects (13.4 ± 5.3 nmol/L, P = 0.013).

CONCLUSIONS

Obese community-dwelling old adults in Iceland have lower 25OHD than their normal-/overweight counterparts. LTPA was associated with a higher 25OHD in normal-/overweight, but not in obese participants. However, fish oil was associated with higher 25OHD independently from obesity status. Thus, vitamin D supplementation is important for obese old adults to maintain vitamin D levels.

Vitamin D status in children with leukemia, its predictors, and association with outcome

BACKGROUND

Children and adolescents with leukemia are potentially at high risk of vitamin D inadequacy, which may have clinical relevance for skeletal morbidity, infections, and cancer outcome. This study aimed to evaluate vitamin D status at the time of diagnosis to investigate its predictors and association with overall survival in children with leukemia.

PROCEDURE

We included all 295 children and adolescents diagnosed with leukemia at our institution between 1990 and 2016 who had available serum sample from the time of diagnosis. We analyzed serum 25-hydroxyvitamin D and parathyroid hormone levels and correlated them with clinical data.

RESULTS

The 25-hydroxyvitamin D level was deficient (< 25 nmol/L), insufficient (25-50 nmol/L), sufficient (50-75 nmol/L), and optimal (> 75 nmol/L) in 6.4%, 26.8%, 39.7%, and 27.1% of the children, respectively. Older age and a more recent time of sampling (calendar year) predicted lower 25-hydroxyvitamin D level. In preschool children (age ≤6 years), lower 25-hydroxyvitamin D level was also associated with acute myeloid leukemia, and a 25-hydroxyvitamin D level < 50 nmol/L was associated with inferior overall survival. In school-aged children (age > 6 years), the 25-hydroxyvitamin D level showed significant seasonal variation.

CONCLUSION

It remains unclear whether vitamin D supplementation in pediatric leukemia patients will improve outcome.

DEFINITION OF VITAMIN D DEFICIENCY IN SCHOOLCHILDREN: SYSTEMATIC REVIEW WITH META-ANALYSIS

BACKGROUND

Vitamin D deficiency is being recognized as a pandemic due to the volume of people affected by the deficiency and the number of illnesses generated or stimulated by the deficiency. There is a lack of consensus in the literature on what is considered vitamin D deficiency [25(OH)D].

OBJECTIVE

This review brings together the most common levels of 25(OH)D found in healthy schoolchildren and what is considered deficient.

METHODS

This systematic review was based on the literature accessed from the electronic databases: MEDLINE, EMBASE, LILACS, SCOPUS and WEB OF SCIENCE. The following descriptors were used in English, Portuguese and Spanish: "Vitamin D"; "Vitamin D deficiency"; "Nutritional Supplements" as well as all their synonyms. The meta-analysis was performed considering the random model. Inclusion criteria: healthy children aged 6 to 12 years, studies that had vitamin D levels, defined vitamin D deficiency.

RESULTS

Of the 191 potentially eligible articles, only six articles were included, with 2618 students in total. The mean value of 25(OH)D was estimated at 18.11 ng/mL with 95% confidence interval. Among the articles found, three were considered deficiency levels below 20 ng/mL, one considered below 18 ng/mL, another below 15 ng/mL, and the latter below 11 ng/ mL. The prevalence of vitamin D deficiency among the articles was 48.6%, 7%, 98%, 64.63%, 19.5%, 28.4%, according to each classification used by the same.

CONCLUSION

The most common definition in the literature of 25(OH)D deficiency in schoolchildren was at levels below 20 ng/mL. No side effects have been reported in studies that used fortification and/or vitamin D supplementation. Daily supplementation is more effective than seasonal supplementation. However, more studies are needed to define what can be considered as optimal levels of 25(OH)D in children.

Vitamin D-related genes and cardiometabolic markers in healthy children: a Mendelian randomisation study

Observational studies show associations between low serum 25-hydroxyvitamin D (25(OH)D) and cardiometabolic risk markers. This Mendelian randomisation study examined associations between cardiometabolic markers in children and SNP in genes related to vitamin D metabolism (DHCR7; group-specific complement (GC); cytochrome P450 subfamily IIR1 (CYP2R1); and CYP24A1) and action (CYP27B1 and VDR). In 699 healthy 8–11-year-old children, we genotyped eleven SNP. We generated a genetic risk score based on SNP associated with low 25(OH)D and investigated associations between this and blood pressure, plasma lipids and insulin. Furthermore, we examined whether SNP related to vitamin D actions modified associations between 25(OH)D and the cardiometabolic markers. All GC and CYP2R1 SNP influenced serum 25(OH)D. A risk score based on four of the six SNP was associated with 3·4 (95 % CI 2·6, 4·2) mmol/l lower 25(OH)D per risk allele (P < 0·001), but was not associated with the cardiometabolic markers. However, interactions were indicated for the three VDR SNP (Pinteraction < 0·081) on associations between 25(OH)D and TAG, systolic blood pressure and insulin, which all decreased with increasing 25(OH)D only in major allele homozygotes (β –0·02 (95 % CI –0·04, –0·01) mmol/l; β –0·5 (95 % CI –0·9, –0·1) mmHg; and β –0·5 (95 % CI –1·4, 0·3) pmol/l, respectively). In conclusion, genetic variation affected 25(OH)D substantially, but the genetic score was not associated with cardiometabolic markers in children. However, VDR polymorphisms modified associations with vitamin D, which warrants further investigation of VDR's role in the relationship between vitamin D and cardiometabolic risk.

Vitamin D status in preschool children and its relations to vitamin D sources and body mass index-Fish Intervention Studies-KIDS (FINS-KIDS)

OBJECTIVES

The aims of this study were to determine vitamin D status (serum 25-hydroxyvitamin D₃ [s-25(OH)D₃]) and examine possible associations between vitamin D status and vitamin D-rich dietary sources, sun exposure, and body mass index in preschool children ages 4 to 6 y.

METHODS

This is a cross-sectional study based on baseline data (collected in January-February 2015) from the two-armed randomized controlled trial Fish Intervention Studies-KIDS (FINS-KIDS) conducted in Bergen, Norway. S-25(OH)D₃ concentration was determined by liquid chromatography-tandem mass spectrometry. Information regarding habitual dietary intake, recent sun vacations, and body mass index were assessed with questionnaires answered by the children's caregivers.

RESULTS

The children (n = 212) had a mean (standard deviation) s-25(OH)D₃ of 60.7 (13.8) nmol/L; 18.9% had s-25(OH)D₃ ≤50 nmol/L. In logistic regression models, non-overweight versus overweight status was inversely associated with s-25(OH)D₃ ≤50 nmol/L (odds ratio: 0.41; 95% confidence interval, 0.18-0.95; P = 0.037). Non-sun versus sun vacations were associated with s-25(OH)D₃ ≤75 nmol/L (odds ratio: 5.33; 95% confidence interval, 1.93-14.77; P = 0.001).

CONCLUSIONS

The majority of the preschool children (81%) had s-25(OH)D₃ >50 nmol/L. Children with overweight status had an increased risk of s-25(OH)D₃ ≤50 nmol/L, and children who had not been on sun vacations were at a greater risk of s-25(OH)D₃ ≤75 nmol/L.

Vitamin D Status and Seasonal Variation among Danish Children and Adults: A Descriptive Study

The aim of the present study was to describe vitamin D status and seasonal variation in the general Danish population. In this study, 3092 persons aged 2 to 69 years (2565 adults, 527 children) had blood drawn twice (spring and autumn) between 2012 and 2014. A sub-sample of participants had blood samples taken monthly over a year. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured by liquid chromatography mass spectrometry, and information on supplement use was assessed from questionnaires. Seasonal variations in 25(OH)D concentrations were evaluated graphically and descriptively, and status according to age, sex, and supplement use was described. It was found that 86% of both adults and children were vitamin D-sufficient in either spring and or/autumn; however, many had a spring concentration below 50 nmol/L. A wide range of 25(OH)D concentrations were found in spring and autumn, with very low and very high values in both seasons. Among adults, women in general had higher median 25(OH)D concentrations than men. Furthermore, vitamin D supplement use was substantial and affected the median concentrations markedly, more so during spring than autumn. Seasonal variation was thus found to be substantial, and bi-seasonal measurements are vital in order to capture the sizable fluctuations in vitamin D status in this Nordic population.

Sun behaviour and physical activity associated with autumn vitamin D status in 4–8-year-old Danish children

Objective

To explore determinants of serum 25-hydroxyvitamin D (s-25(OH)D) during autumn in young, Caucasian children not consuming vitamin D-fortified foods or supplements, and explore differences in sun behaviours between pre-school and school children.

Design

In September–October, s-25(OH)D was measured by LC–MS/MS; physical activity, sun behaviours and vitamin D intake were assessed with questionnaires.

Setting

Baseline data from the ODIN Junior trial at 55°N.

Subjects

Children aged 4–8 years (n130), of whom 96% gave blood samples.

Results

Mean s-25(OH)D was 56·8 (sd12·5) nmol/l and positively associated with fat-free mass index (P=0·014). Children being active 6–7 h/week had 5·6 (95% CI 1·1, 10·0) nmol/l higher s-25(OH)D than less active children (P=0·014). Children seeking shade sometimes or rarely/never had 7·0 (95% CI 1·2, 12·9;P=0·018) and 7·2 (95% CI 0·8, 13·6;P=0·028) nmol/l higher s-25(OH)D, respectively, than children always/often seeking shade. Pre-school children had more sun-safe behaviour than school children in terms of use of a hat, sunscreen and sunscreen sun protection factor (P<0·05). In school but not pre-school children, using a hat rarely/never was associated with 12·1 (95% CI 2·5, 21·7;P=0·014) nmol/l higher s-25(OH)Dv. always/often (Pinteraction=0·019). Vitamin D intake was not associated with s-25(OH)D (P=0·241).

Conclusions

Physical activity and sun behaviours are associated with s-25(OH)D in young children. Identifying factors influencing autumn s-25(OH)D is relevant to optimize levels before sun exposure diminishes. Strategies to reduce risk of inadequacy should consider risk of skin cancer and sunburn, and could include fortification and/or vitamin D supplementation.

Serum 25-hydroxyvitamin D levels showed strong seasonality but lacked association with vitamin D intake in 3-year-old Japanese children

Current guidelines provide a universal recommendation on vitamin D intake to prevent insufficiency. However, the relative influence of food, UVB and other factors on serum 25-hydroxyvitamin D (25(OH)D) insufficiency has been poorly investigated in preschool children. We assessed serum 25(OH)D quantities and their association with vitamin D intake using a brief-type self-administered diet history questionnaire for children aged 3-6 years (BDHQ3y), outdoor playing time and background UVB radiation level among 574 36-month-old Japanese children living at latitude 35°N. The average serum 25(OH)D concentration was 23·5 (sd 6·1) ng/ml, and 170 (29·6 %) children had vitamin D insufficiency (<20 ng/ml) despite high consumption of fish. Multiple logistic regression adjusting for social factors showed that when background UVB radiation level was <15 kJ/m2 (monthly average), there was a 1·89 (95 % CI 1·31, 2·74) times higher risk of vitamin D insufficiency, to which vitamin D intake nor time spent outdoors were significantly associated. ANOVA showed that the contribution of the variability in vitamin D intake on the variability of serum 25(OH)D level was 1·8 % of that of UVB exposure. The correlation between vitamin D intake and serum 25(OH)D level was not stronger when limited to measurements in winter. We found that nearly 30 % of 3-year-old Japanese children had vitamin D insufficiency despite high consumption of fish and living at relatively low latitude. We failed to observe an association between vitamin D intake and the risk of vitamin D insufficiency. This may be due to the extremely limited access to vitamin D-fortified food and supplements for children in Japan.

A History of Cow's Milk Allergy Is Associated with Lower Vitamin D Status in Schoolchildren

BACKGROUND/AIMS

Vitamin D insufficiency is common in children. We aimed to evaluate the main determinants of vitamin D status in Finnish school-aged children, including the history of allergic diseases.

METHODS

We conducted a cross-sectional study on 171 ten-year-olds where serum 25-hydroxyvitamin D (25[OH]D) levels were measured, and data on food consumption and use of vitamin D supplements were collected. The history of allergic diseases was evaluated with a validated questionnaire.

RESULTS

Vitamin D insufficiency (<50 nmol/L) was observed in 16% of the children. In children with a history of cow's milk allergy, the mean 25(OH)D levels were lower than in children without allergy (60.5 ± 12.6 nmol/L vs. 75.5 ± 22.3 nmol/L, p = 0.004). Lack of vitamin D supplementation, female gender, non-Caucasian ethnicity, and a history of milk allergy were associated with lower vitamin D status.

CONCLUSION

The vitamin D status in our study sample of Finnish schoolchildren was sufficient, which suggests that health policy strategies - such as the recommendation of vitamin D supplementation and the fortification of food products with vitamin D - have been successful in improving vitamin D status in children. Special concern should be given to children with a history of milk allergy to ensure their vitamin D sufficiency.

Obesity is associated with vitamin D deficiency in Danish children and adolescents

BACKGROUND

Sufficient serum concentrations of vitamin D are required to maintain bone health during growth. The aims of this study were to determine whether vitamin D deficiency is more prevalent among children and adolescents with obesity compared to their normal weight peers and to identify clinical and biochemical variables associated with vitamin D deficiency.

METHODS

One thousand four hundred and eighty-four children and adolescents with overweight/obesity and 2143 population-based controls were recruited from the Danish Childhood Obesity Biobank. Anthropometric variables and fasting concentrations of serum 25-hydroxy vitamin D (25-OH-D), plasma parathyroid hormone (PTH), calcium and phosphate were assessed at baseline. Vitamin D deficiency was defined as serum 25-OH-D concentrations <30 nmol/L. Linear and logistic regressions were used to identify variables associated with vitamin D deficiency.

RESULTS

A total of 16.5% of the children and adolescents with obesity (body mass index [BMI] standard deviation score [SDS]>2.33) exhibited vitamin D deficiency, with an odds ratio (OR) 3.41 (confidence interval [CI]: 2.27-5.71; p<0.0001) for being vitamin D deficient compared to their normal weight peers. BMI-SDS was independently and inversely associated with serum 25-OH-D concentrations. Other independent risk factors for vitamin D deficiency were being older than 14 years (OR: 2.39; CI: 1.28-4.48; p=0.006), more than 4 daily hours of screen time (OR: 4.56; CI: 2.59-8.05; p<0.0001) and blood sample assessment during winter-spring (OR: 6.44; CI: 4.47-9.26; p<0.0001).

CONCLUSIONS

Vitamin D deficiency was common among Danish children and adolescents with obesity. The degree of obesity was independently associated with lower serum 25-OH-D concentrations.

Non-musculoskeletal benefits of vitamin D

The aim of this study is to determine and critically evaluate the plausible relationships of vitamin D with extra-skeletal tissues in humans. Severe vitamin D deficiency results in rickets in children and osteomalacia in adults; these beneficial effects in the musculoskeletal system and certain physiological functions are well understood. Nevertheless, mounting reports support additional beneficial effects of vitamin D, outside the musculoskeletal system. This review explores the recent advances in knowledge about the non-skeletal effects of vitamin D. Peer-reviewed papers were extracted from research databases using key words, to assess correlations between vitamin D and extra-skeletal diseases and conditions. As per the guidelines of the Preferred Reporting Items for Systematic Reviews (PRISMA); general interpretations of results are included; taking into consideration the broader evidence and implications. This review summarizes current knowledge of the effects of vitamin D status on extra-skeletal tissues with special attention given to relationships between vitamin D status and various diseases commonly affecting adults; the effects of intervention with vitamin D and exposure to sunlight. Evidence suggests that vitamin D facilitates the regulation of blood pressure; and cardiac; endothelial; and smooth muscle cell functions; playing an important role in cardiovascular protection. In addition; 1,25(OH)₂D improves immunity; subdues inflammation; and reduces the incidence and severity of common cancers; autoimmune diseases and infectious diseases. Almost all adequately powered; epidemiological and biological studies that use; adequate doses of vitamin D supplementation in D-deficient populations have reported favorable outcomes. These studies have concluded that optimizing 25(OH)D status improves the functionality of bodily systems; reduces comorbidities; improves the quality of life; and increases survival. Although accumulating evidence supports biological associations of vitamin D sufficiency with improved physical and mental functions; no definitive evidence exists from well-designed; statistically powered; randomized controlled clinical trials. Nevertheless, most studies point to significant protective effects of vitamin D in humans when the minimum 25(OH)D serum level exceeds 30ng/mL and is maintained throughout the year.

Vitamin D insufficiency/deficiency is associated with insulin resistance in Brazilian children, regardless of body fat distribution

OBJECTIVE

To assess the prevalence of vitamin D insufficiency and deficiency and its association with cardiometabolic risk factors, controlled by adiposity, in a representative sample of prepubescent children.

DESIGN

Cross-sectional population-based study. Body composition was evaluated by dual-energy X-ray absorptiometry. Anthropometric measures and blood pressure were performed. Laboratory analyses were performed to determine the levels of vitamin D (25-hydroxyitamin D; 25(OH)D), glucose, insulin, serum lipids and intact parathyroid hormone. Dietary intake was assessed by three 24 h recalls.

SETTING

Viçosa, Minas Gerais, Brazil, 2015.

SUBJECTS

Representative sample of 378 children aged 8 and 9 years from urban schools.

RESULTS

Inadequate serum concentrations of 25(OH)D were diagnosed in more than half of the children and none of them met the recommended vitamin D intake. After adjusting for confounding factors in the multiple regression analysis, lower prevalence of insulin resistance and hypertriacylglycerolaemia was found in children with serum 25(OH)D levels ≥75 nmol/l (prevalence ratio=0·25; 95 % CI 0·08, 0·85) and ≥50 nmol/l (prevalence ratio=0·61; 95 % CI 0·37, 0·99), respectively. However, after adjusting for different indicators of adiposity, insulin resistance remained independently associated and the association with hypertriacylglycerolaemia was lost after adjusting for central adiposity. The prevalence of vitamin D insufficiency/deficiency was associated with the number of cardiometabolic alterations in children.

CONCLUSIONS

The study results showed that prevalence of vitamin D insufficiency/deficiency was high among the children and insulin resistance was the main cardiometabolic alteration associated with this condition, even in a tropical climate country such as Brazil.

Severe hypovitaminosis D in active tuberculosis patients and its predictors

BACKGROUND & AIMS

Tuberculosis (TB) patients have a significant vitamin D deficiency (VDD) endemic, which may be closely related to the onset and progress of the disease. The comorbidity of diabetes (DM) and TB has posed an increasing challenge in recent years. However, the influence of DM on TB and the possible mechanism are still uncertain. We carried out this study to identify the nutritional status of vitamin D (VD) in TB patients in a northern city in China (latitude 36° N) and investigate the possible predictors of severe vitamin D deficiency (SVDD).

METHODS

A cross-sectional study including 461 active TB patients (192 with and 269 without DM) were randomly selected from Qingdao Chest Hospital from June 2015 to August 2016. We measured serum 25 hydroxyvitamin D [25(OH)D], and investigated the association between sociodemographic, dietary intake, DM, body mass index (BMI), severity of initial TB signs and symptoms (TB score) and VD status. Multivariate logistic regression analysis was used to define the possible predictors of SVDD.

RESULTS

The median serum 25(OH)D concentration was 8.50 ng/mL. Of the 461 TB patients included, 383 (83.1%) had VDD [25(OH)D < 20 ng/mL], and 217 (47.1%) had SVDD [25(OH)D < 8 ng/mL]. The variables associated with serum 25(OH)D concentrations were DM, outdoor activity level, TB score and BMI (p < 0.05). Patients with severe TB score had nearly 5 fold higher risk of having SVDD compared with those in mild subgroup [OR (95% CI) = 4.919 (2.644-9.150), p < 0.001]. Low outdoor activity level also increased the odds of SVDD, while DM and high fish consumption showed protect effects.

CONCLUSIONS

Severe hypovitaminosis D is prevalent in active TB patients, and the main predictors of SVDD were severe TB score, low outdoor activity, inadequate fish consumption. Lowered serum 25(OH)D may be associated with increased risk of TB in DM.

Common genetic variants are associated with lower serum 25-hydroxyvitamin D concentrations across the year among children at northern latitudes

In a longitudinal study including 642 healthy 8–11-year-old Danish children, we investigated associations between vitamin D dependent SNP and serum 25-hydroxyvitamin D (25(OH)D) concentrations across a school year (August–June). Serum 25(OH)D was measured three times for every child, which approximated measurements in three seasons (autumn, winter, spring). Dietary and supplement intake, physical activity, BMI and parathyroid hormone were likewise measured at each time point. In all, eleven SNP in four vitamin D-related genes: Cytochrome P450 subfamily IIR1 (CYP2R1); 7-dehydrocholesterol reductase/nicotinamide adenine dinucleotide synthetase-1(DHCR7/NADSYN1); group-specific complement (GC); and vitamin D receptor were genotyped. We found minor alleles of CYP2R1 rs10500804, and of GC rs4588 and rs7041 to be associated with lower serum 25(OH)D concentrations across the three seasons (all P<0·01), with estimated 25(OH)D differences of −5·8 to −10·6 nmol/l from major to minor alleles homozygosity. In contrast, minor alleles homozygosity of rs10741657 and rs1562902 in CYP2R1 was associated with higher serum 25(OH)D concentrations compared with major alleles homozygosity (all P<0·001). Interestingly, the association between season and serum 25(OH)D concentrations was modified by GC rs7041 (Pinteraction=0·044), observed as absence of increase in serum 25(OH)D from winter to spring among children with minor alleles homozygous genotypes compared with the two other genotypes of rs7041 (P<0·001). Our results suggest that common genetic variants are associated with lower serum 25(OH)D concentrations across a school year. Potentially due to modified serum 25(OH)D response to UVB sunlight exposure. Further confirmation and paediatric studies investigating vitamin D-related health outcomes of these genotypic differences are needed.