Vitamin D and Cardiovascular Risk: which Implications in Children?

Longitudinal Associations Between Vitamin D Status and Cardiometabolic Risk Markers Among Children and Adolescents

CONTEXT

Vitamin D status has previously been associated with cardiometabolic risk markers in children and adolescents. In particular, it has been suggested that children with obesity are more prone to vitamin D deficiency and unfavorable metabolic outcomes compared with healthy-weight children.

OBJECTIVE

To conduct a longitudinal study assessing this association in children and stratify by body mass index (BMI) category.

METHODS

Children from the pan-European IDEFICS/I.Family cohort with at least one measurement of serum 25-hydroxyvitamin D [25(OH)D] at cohort entry or follow-up (n = 2171) were included in this study. Linear mixed-effect models were used to assess the association between serum 25(OH)D as an independent variable and z-scores of cardiometabolic risk markers (waist circumference, systolic [SBP] and diastolic blood pressure [DBP], high- [HDL] and low-density lipoprotein, non-HDL, triglycerides [TRG], apolipoprotein A1 [ApoA1] and ApoB, fasting glucose [FG], homeostatic model assessment for insulin resistance [HOMA-IR], and metabolic syndrome score) as dependent variables.

RESULTS

After adjustment for age, sex, study region, smoking and alcohol status, sports club membership, screen time, BMI, parental education, and month of blood collection, 25(OH)D levels were inversely associated with SBP, DBP, FG, HOMA-IR, and TRG. The HOMA-IR z-score decreased by 0.07 units per 5 ng/mL increase in 25(OH)D. The 25(OH)D level was consistently associated with HOMA-IR irrespective of sex or BMI category.

CONCLUSION

Low serum 25(OH)D concentrations are associated with unfavorable levels of cardiometabolic markers in children and adolescents. Interventions to improve vitamin D levels in children with a poor status early in life may help to reduce cardiometabolic risk.

Association between vitamin D, depression, and sleep health in the National Health and Nutrition Examination Surveys: a mediation analysis

OBJECTIVE

This study aimed to assess the association between vitamin D and sleep health and to investigate whether depression could mediate this relationship.

METHODS

A cross-sectional analysis was performed using the 2005-2014 US National Health and Nutrition Examination Survey (NHANES) data. The logistic regression models were conducted to evaluate association of serum vitamin D concentrations with sleep health and depression. Mediation analyses were conducted to investigate the mediated effects of depression on the association of vitamin D with sleep health.

RESULTS

In multivariate logistic models, vitamin D was found to be negatively associated with an increased risk of poor sleep health, with an odds ratio (OR) of vitamin D deficiency versus sufficiency was 1.256 (95% CI = 1.084-1.455). Additionally, univariate logistic models showed that vitamin D was also negatively associated with depression risk (vitamin D deficiency vs. sufficiency: OR = 1.699, 95% CI = (1.373-2.103). Further mediation analyses showed that the association of vitamin D with sleep health was mediated by depression, with the mediating effects of depression accounted for 44.56% of the total effects.

CONCLUSION

Vitamin D affects sleep health directly and indirectly through depression. The results suggest that interventions increasing intake of vitamin D should be prioritized to promote sleep health of persons with or at risk of depression.

Analysis of hot trends in research on the association between vitamin D and cardiovascular disease

Objective

Vitamin D deficiency is the most common nutrient deficiency. Numerous studies suggest that vitamin D is an independent risk factor for cardiovascular disease. The objective is to visualize the research hotspots and evolution trends of the correlation between vitamin D and cardiovascular disease by using multivariate statistics and social network analysis techniques and to compare adult research with that of children in this field.

Methods

(Vitamin D [MeSH Major Topic]) AND (cardiovascular disease [MeSH Major Topic]) were retrieved from the PubMed database by time period. The bibliographic items co-occurrence matrix builder (BICOMB) was adopted to extract high-frequency subject terms and establish the core subject term co-occurrence matrix. With the Netdraw function of Ucinet 6.0 software, the social network of core subject terms was completed.

Results

Before 2010, there was a slow increase in the number of research papers covering all age groups in this field (157, 54, 84, and 211 papers were published in stages 1-4, respectively). From 2010 to 2020, there were 1,423 papers retrieved, showing a significantly increased research heat. The overall development trend of the research on the association between vitamin D and cardiovascular disease in children is similar to that in all age groups. From 2010 to 2020, 122 related papers were published (while before 2009, there were only 43 papers in all), presenting a good overall development trend. The social network analysis of core subject terms showed gradually increased correlations between research hotspots, from the early studies limited on the physiological function of vitamin D in cardiovascular diseases, to the role of vitamin D in the comorbidities of various cardiovascular diseases and its value as an intervention measure. Researches on the association between vitamin D and cardiovascular disease has a good overall development trend. Study of the mechanisms and the role of vitamin D in the common co-morbidities of cardiovascular disease and its therapeutic value will be the focus of future research.

Vitamin D Supplementation of 7–8 Years Old Children from Different Geographical Areas (48–52° North Latitude): Cross Sectional Study

Background. The prevalence of vitamin D deficiency in children by their geographic latitude of residence requires follow-up study. This is crucial for implementation of preventive measures that can reduce the risk of developing pathological conditions associated with vitamin D deficiency.

Objective. The aim of the study is to study the vitamin D supplementation of 7–8 years old children living in different geographical latitudes of one subject of Russian Federation.

Methods. The study included relatively healthy children living in three geographical areas (northern — 52°, central — 50°, southern — 48°) of one region (Khabarovsk Krai). Vitamin D supplementation was evaluated by 25(OH)D serum concentration via enzyme-linked immunosorbent assay. Vitamin D insufficiency was diagnosed at 25(OH)D concentration of 21–30 ng/ml, deficiency — 10–20 ng/ml, severe deficiency — < 10 ng/ml; optimal 25(OH)D concentration was considered as 30–100 ng/ml.

Results. The increase in prevalence of vitamin D deficiency and insufficiency has been revealed with gradual increase from southern (57%) to central (73%) and northern (83%) geographic areas in 7–8 years old children living in the same region. The prevalence of vitamin D deficiency and insufficiency (25(OH)D ≤ 30 ng/mL) among children living in the northern geographic area was greater by 3.8-fold (95% confidence interval 1.2–12.7) then among peers living in the southern areas.

Conclusion. One factor affecting 25(OH)D serum concentration in children of this region is the insolation level determined by the geographical latitude of residence. The 4°N difference is significant in determining vitamin D status in residents of relatively high latitudes. Further studies of factors associated with 25(OH)D concentration in children living in different latitudes are required (insolation level, number of sunny days per year, food and household characteristics in families).

Serum 25-Hydroxyvitamin D correlates with systolic blood pressure in obese male schoolchildren

INTRODUCTION

Childhood obesity is associated with an increased risk of chronic diseases. We aimed to examine the relation between serum levels of 25-hydroxyvitamin D (25[OH]D) and blood pressure in obese schoolchildren.

MATERIAL AND METHODS

Cross-sectional study in school-age children with obesity. The serum levels of 25(OH)D were measured and classified as sufficient or insufficient/deficient. Blood pressure was measured. Normal values were considered <90th percentile, elevated blood pressure ≥90th to <95th percentiles, and hypertension ≥95th percentile, according to blood pressure reference tables, specific for age, sex, and height. The Pearson correlation was performed.

RESULTS

256 obese schoolchildren (123 [48.0%] females and 133 [51.9 %] males) were evaluated. The prevalence rates of vitamin D deficiency, insufficiency, and sufficiency were 23.4%, 52.3%, and 24.2%, respectively. Normal blood pressure was observed in 101 (39.4%) children; the frequencies of elevated blood pressure and hypertension were 10.9% and 49.6%, respectively. A moderate inverse correlation of 25(OH) D levels with systolic blood pressure levels (r = -0.54, p = 0.03) was observed. When analyzed by sex, a significantly high inverse correlation between 25(OH)D levels and systolic blood pressure was observed in males (r=-0.85 and p=<0.001). No significant correlation was found in females (systolic r=-0.16 and p=0.67; diastolic r= -0.15 and p=0.812). When performing the multiple regression analysis, the 25(OH)D levels and body mass index (BMI) were the significant predictors for systolic blood pressure.

CONCLUSIONS

We identified an inverse correlation between 25[OH]D levels and systolic blood pressure in male schoolchildren with obesity.

Analysis of Development Trends of the Research Hotspots of Vitamin D in Children

OBJECTIVE

Using multivariate statistics and social network analysis techniques, we present a realistic and intuitive visualization of the research hotspots and development trends of vitamin D in children.

METHODS

The Medical Subject Headings (MeSH) term "vitamin D" was used to search all the publications (the study subjects were 0-18 years old) included in PubMed by time period. The subject terms for each development stage were extracted, the high-frequency subject terms were extracted using the Bibliographic Items Co-occurrence Matrix Builder (BICOMB), and a core subject term co-occurrence matrix was established. The Netdraw function of Ucinet 6.0 software was used to complete the social network drawing of the core subject term co-occurrence matrix to form a co-word network diagram composed of core subject terms.

RESULTS

Prior to 1979, there were 890 papers with 1,899 core subject terms; from 2010 to 2020, there were 3,773 papers with 12,682 core subject terms. Before 1979, the research direction of vitamin D in children focused on vitamin D in the classical regulation of calcium and phosphorus metabolism. From 1980 to 1989, studies focused on vitamin D metabolites and therapeutic drugs such as "calcitriol" and "calcifediol." From 1990 to 1999, studies focused on "calcitriol" and its association with "psoriasis," "chronic renal failure," and "dermatological drugs." From 2000 to 2009, studies focused on "vitamin D" and "vitamin D deficiency." From 2010 to 2020, studies focused on "vitamin D₃" and its association with "vitamins," "bone mineral density protectants," "asthma," "obesity," "pregnancy complications" and "fetal blood."

CONCLUSION

Since 2010, the research direction of vitamin D in children has been growing rapidly, and the overall development trend is good. Studies extend from the study of the skeletal effect of vitamin D to the study of its extraskeletal effect and the investigation of mechanisms of its association with related diseases.

Low serum 25-Hydroxy (OH) vitamin D levels are associated with increased arterial stiffness in healthy children: An echocardiographic study from Turkey

OBJECTIVE

Arterial stiffness refers to arterial wall rigidity, particularly in central vessels, and is an independent predictor of cardiovascular disease in many chronic diseases. 25-Hydroxy (OH) vitamin D has beneficial effects on blood pressure, vascular endothelial function, and arterial stiffness; most importantly, its deficiency is common worldwide. Therefore, we aimed to elucidate the role of 25-OH vitamin D deficiency in arterial stiffness development and its relationship with arterial stiffness in healthy children.

METHODS

This study included 80 patients with low levels of 25-OH vitamin D and 40 healthy control subjects. The study participants were then divided into three groups: group 1 consisted of patients with a deficient 25-OH D level of < 19.9 ng/ml, group 2 with an insufficient 25-OH D level between 20 and 29.9 ng/ml; group 3 were considered control group with a sufficient serum 25-OH vitamin D level of ≥30 ng/ml. Aortic strain, distensibility, stiffness index, and standard left ventricular measurements were calculated using M-mode echocardiographic data.

RESULTS

Left ventricular mass index (LVMI) and inter-ventricular septal diastolic thickness (IVST) appeared to increase in group 1 compared to groups 2 and 3. Aortic strain and distensibility were significantly decreased in group 1, whereas aortic stiffness index and elastic modulus were significantly increased. The aortic stiffness index was negatively correlated with serum 25-OH vitamin D levels; however, aortic strain, aortic distensibility, and LVMI were positively correlated.

CONCLUSIONS

Our study results revealed a significant relationship between 25-OH vitamin D levels indicative of a deficiency and aortic stiffness. Hence, we suggest that arterial stiffness may also occur in healthy children with a 25-OH vitamin D deficiency. Future in-depth studies are needed to understand the exact mechanisms underlying the aortic stiffness development associated with 25-OH vitamin D deficiency.

Cardiovascular Risk Factors in Children with Obesity, Preventive Diagnostics and Possible Interventions

The increasing burden of obesity plays an essential role in increased cardiovascular morbidity and mortality. The effects of obesity on the cardiovascular system have also been demonstrated in childhood, where prevention is even more important. Obesity is associated with hormonal changes and vascular dysfunction, which eventually lead to hypertension, hyperinsulinemia, chronic kidney disease, dyslipidemia and cardiac dysfunction—all associated with increased cardiovascular risk, leading to potential cardiovascular events in early adulthood. Several preventive strategies are being implemented to reduce the cardiovascular burden in children. This paper presents a comprehensive review of obesity-associated cardiovascular morbidity with the preventive diagnostic workup at our hospital and possible interventions in children.

Vitamin D status and blood pressure in children and adolescents: a systematic review of observational studies

BACKGROUND

Childhood hypertension is a growing public health problem. Simultaneously, hypovitaminosis D is widespread in this population and could be associated with hypertension. This study systematically reviewed the literature on the relationship between vitamin D status and blood pressure (BP) in children and adolescents.

METHODS

Following the PRISMA guidelines, PUBMED, MEDLINE, CINAHL, EMBASE, Cochrane Library, and ClinicalTrials.gov and the gray literature without language or time restrictions were searched. We included observational studies, assessed their risk of bias, and extracted data on population characteristics, vitamin D status and BP measurements, and the association between the two variables. A narrative analysis of the studies was performed.

RESULTS

In total, 85 studies were included. Prospective cohort studies showed no association between vitamin D and BP, and generally, they were flawed. Also, the majority of non-prospective cohort studies (cross-sectional, retrospective, case-control) did not report an association between vitamin D and BP. They were mostly flawed regarding BP measurement and adjusting to potential confounders.

CONCLUSION

The results on the relationship between vitamin D status and BP in children and adolescents varied between the studies, and mainly pointed towards lack of association.

Effect of Hypovitaminosis D on Lipid Profile in Hypothyroid Patients in Saudi Arabia

Background

Hypothyroidism is believed to be associated with dyslipidemia and is considered a risk factor for the development of atherosclerotic cardiovascular diseases (ASCVD). Vitamin D, due to its steroid hormone action, retains cell function and controls the metabolism of lipids. Therefore, the present study was carried out to show the association of the risk factors of ASCVD and deficiency of thyroid hormones and vitamin D levels since no previous studies have been performed on Saudi patients before. Methodology. A retrospective cohort study was carried out on 400 hypothyroid patients. Medical records of those patients were followed up and were classified as normal and hypothyroid patients according to their thyroid-stimulating hormone levels. TSH, vitamin D, and lipid profiles were determined using the ELISA technique.

Result

Total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels were significantly higher in hypothyroid patients than those in the normal group. We have found a significant correlation between TSH levels and the risk factors of ASCVD (total cholesterol, triglycerides, and LDL-C). Moreover, a significant correlation between vitamin D levels and the risk factors of ASCVD (total cholesterol, triglycerides, and LDL-C) has been found. In addition, there is a correlation between deficiency of Vit D and low-TSH levels (95% CI 1.092-4.05) indicating a higher risk for the development of ASCVD among those patients.

Conclusion

Hypothyroid and vitamin D-deficient patients must be screened regularly at an early stage to predict and also to prevent cardiovascular diseases. Moreover, an adequate supply of vitamin D and TH should be given to those patients to prevent cardiovascular diseases at an early stage.

Meteorological Condition and Air Pollution Exposure Associated with Vitamin D Deficiency: A Cross-Sectional Population-Based Study in China

Objective

The aim of this study was to investigate the status of Vitamin D deficiency and the effect of environmental factors on Vitamin D levels so as to provide theoretical support for public health promotion in this region.

Methods

A total of 22,387 subjects who underwent a physical examination at the center in the West China Hospital, Sichuan University, between April, 2018 and May, 2020 were enrolled in this study. Their data on gender, age, inspection date, serum 25 hydroxyvitamin D (25-(OH) D), parathyroid hormone (PTH), and total calcium were retrospectively reviewed. Next, the percentage of Vitamin D status was compared in different sex and age groups, and the fluctuation of Vitamin D level was described in relation to the change of environment. Finally, the univariable and multivariable linear regression analyses were performed to explore the risk and protective factors of Vitamin D deficiency.

Results

The proportion of Vitamin D deficiency in this area was 42.17%, and it was significantly higher among women and young people. The fluctuation trend of 25-(OH) D levels are consistent with temperature and solar radiation, and opposite to air quality, in the whole year. There was a positive relationship between 25-(OH) D levels with temperature and solar radiation; however, parathyroid hormone, female and AQI were negatively correlated with Vitamin D levels.

Conclusion

Vitamin D deficiency is common in subtropic areas, such as Sichuan Basin, which is related to solar radiation and air pollution.

Cardiovascular Risk in Children: Focus on Pathophysiological Aspects

Cardiovascular diseases are the leading cause of death, disability, and health care costs in industrialized countries. In general, cardiovascular diseases occur in adulthood, but cardiovascular damage, including stiffening of the arteries, begins very early. Already in the first decade of life, alterations that will favor the formation of atherosclerotic plaques may be present. Cardiovascular risk factors, associated with genetic predisposition, may trigger a sequence of pathophysiological changes which are associated with the progression of the atherosclerosis process. In this frame, the role of obesity has been increasingly emphasized. Different mechanisms linking obesity to cardiovascular disease have been postulated. Endothelial dysfunction and subclinical inflammation seem to be related to the worsening of cardiovascular risk factors in obese subjects and might have an essential role in the development of insulin resistance and the initiation and progression of atherosclerotic lesions. Excess weight, and in particular visceral adiposity, are associated with hypertrophy and hyperplasia of the adipocytes, increased secretion of adipokines and inflammatory cytokines and increase in serum uric acid levels. The list of obesity-related biomarkers associated with cardiovascular damage is rapidly expanding and their importance has already been described in children as well. Pathophysiological changes involved in determining early cardiovascular damage starting from childhood are discussed in this Special Issue.