The Association Between Vitamin D Deficiency and Metabolic Syndrome in Korean Adolescents

Serum 25-Hydroxyvitamin D Is Associated With Prediabetes, Type 2 Diabetes Mellitus, and Insulin Resistance in Children: A Systematic Review and Dose-Response Meta-analysis of Epidemiologic Studies

CONTEXT

Although several investigations have been conducted on the association between serum vitamin D levels and prediabetes and type 2 diabetes mellitus (T2DM) in children and adolescents, their findings are inconsistent.

OBJECTIVE

We conducted a systematic review and dose-response meta-analysis to summarize this subject.

DATA SOURCES

The electronic databases of ISI Web of Science, Scopus, PubMed, and motor engineering of Google Scholar were comprehensively searched up to May 2023.

DATA EXTRACTION

Epidemiologic studies that investigated the risk of hyperglycemia and insulin resistance in relation to serum 25-hydroxy vitamin D levels in children and adolescents were included.

DATA ANALYSIS

Twenty-two investigations, with a total of 38 622 participants, were systematically reviewed. Meta-analysis of 15 studies (n = 32 720 participants) showed that participants with the highest serum vitamin D levels had 42% lower risk of hyperglycemia, compared with those in the lowest category of serum vitamin D levels (relative risk [RR] = 0.58; 95%CI, 0.48, 0.71). Moreover, pooling 8 studies (n = 10 465 participants) illustrated that highest serum vitamin D level was associated with a 44% lower risk of insulin resistance compared with the lowest serum vitamin D level (RR = 0.56; 95%CI, 0.37, 0.83). Based on linear dose-response analysis, each 10 nmol/L increment in serum 25-hydroxy vitamin D was associated with a 6% decreased risk of hyperglycemia and insulin resistance in children. Furthermore, nonlinear dose-response analysis revealed that increasing serum vitamin D concentration from 40 nmol/L to sufficient values (>50 nmol/L) was associated with a decreasing trend in risk of hyperglycemia and insulin resistance.

CONCLUSION

This meta-analysis revealed inverse associations between serum vitamin D levels and hyperglycemia and insulin resistance in children and adolescents, in a dose-response manner. Increasing serum vitamin D concentration from 40 nmol/L to sufficient values (>50 nmol/L) was associated with a decreasing trend in hyperglycemia and insulin resistance risk. Systematic Review Registration: PROSPERO registration no. CRD42023458155.

The association between serum vitamin D levels and abnormal lipid profile in pediatrics: A GRADE-assessed systematic review and dose-response meta-analysis of epidemiologic studies

CONTEXT

Several studies have investigated the relationship between serum vitamin D and dyslipidemia in children and adolescents, but the findings have been contradictory.

OBJECTIVE

The current systematic review and dose-response meta-analysis investigated the serum vitamin D - dyslipidemia relationship in children and adolescents.

DATA SOURCES

ISI Web of Science, Scopus, MEDLINE (PubMed), EMBASE databases, and Google Scholar, were searched up to December 2022.

DATA EXTRACTION

Observational studies that investigated the odds of dyslipidemia in categories of serum vitamin D levels in children were included, and their data were extracted.

DATA ANALYSIS

Pooling of 17 effect sizes from 15 studies (39 342 participants) showed that subjects with higher serum vitamin D had 27% lower odds of hypertriglyceridemia (odds ratio [OR] = 0.73; 95% confidence interval [CI]: 0.60, 0.88). A meta-analysis of 18 effect sizes from 16 studies (39 718 participants) illustrated that highest vs lowest serum vitamin D was related to 22% lower odds of low high-density lipoprotein cholesterol (HDL-c) (OR = 0.78; 95% CI: 0.66, 0.91). Also, a nonlinear association between serum vitamin D and odds of abnormal lipid profile was found: elevating values of 25-hydroxyvitamin D from 35 nmol/L to 55 nmol/L was associated with a decreasing trend in odds of hypertriglyceridemia, hyper low-density lipoprotein cholesterolemia, hypercholesterolemia, and hypo HDL-cholesterolemia. However, no significant linear association was observed. Based on the Grading of Recommendations, Assessment, Development and Evaluations (GRADE), the certainty of all evidence was rated as high.

CONCLUSION

This meta-analysis revealed that the level of 25-hydroxyvitamin D was inversely related to odds of abnormal serum triglycerides and HDL-c in children and adolescents. Increasing serum vitamin D from 35 nmol/L to 55 nmol/L was associated with a decreasing trend in the odds of abnormal serum triglycerides, HDL-c, low-density lipoprotein cholesterol, and total cholesterol in children.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 42023400787.

The Association Between Glycated Hemoglobin (HbA1c) Level and Vitamin D Level in Diabetes Mellitus Patients: A Cross-Sectional Study

BACKGROUND

Prior research has established noteworthy correlations between inadequate glycemic management and a multitude of problems in individuals diagnosed with diabetes mellitus (DM).

METHODS

This is a cross-sectional retrospective study that was conducted at the Jeddah Center for the Care of Diabetes and Blood Pressure Patients, Jeddah, Kingdom of Saudi Arabia. The medical records of patients diagnosed with DM between 2015 and 2022 were identified and reviewed for the purpose of this study. Pearson correlation coefficient was used to examine the correlation between glycated haemoglobin (HbA1c) and vitamin D levels. Multiple linear regression analysis was applied to identify the association between HbA1c and vitamin D levels.

RESULTS

A total of 152 patients were included in this study. The mean HbA1c level for the patients in this study was 8.2% (SD: 1.7). The median vitamin D level for the patients was 20.9 ng/ml (interquartile range (IQR): 13-30.4). More than half of the patients (n= 92; 60.5%) were found to have vitamin D insufficiency. Pearson correlation coefficient identified that there is an inverse correlation between the level of HbA1c and vitamin D level (r= -0.21 (95%CI -0.36 to -0.06; p-value= 0.007). Multiple linear regression analysis (adjusting for age and type of DM) identified that poor glycaemic control has a negative association with vitamin D level (regression coefficient (B) = -0.027; 95%CI -0.053 to - 0.001; p-value= 0.039).

CONCLUSION

Poor glycaemic control is associated with vitamin D deficiency in DM patients. It is recommended that patients with DM adhere to their medications and maintain a healthy lifestyle in order to manage their condition. This will improve their overall health, specifically their vitamin D status.

Vitamin D improves hepatic alterations in ACE1 and ACE2 expression in experimentally induced metabolic syndrome

Metabolic Syndrome (MetS) is a term used to describe a cluster of pathophysiological, biochemical, and metabolic criteria; including high Blood Pressure (BP), high cholesterol, dyslipidaemia, central obesity and Insulin Resistance (IR). The Renin Angiotensin System (RAS) has a regulatory function in BP, hydroelectrolyte balance, and cardiovascular function. RAS is composed of angiotensinogen (AGT), (Ang I), (Ang II), (ACE1), (ACE2), (AT1R), (AT2R), and (Ang 1-7). Vitamin D had been proved to act as a protective factor against MetS. Therefore, the study is pursued to explore vitamin D supplementation roles on hepatic RAS in MetS experimental model. At first, 36 males Albino rats were separated into 4 groups and induced to MetS under controlled circumstances for 3 months. Then, data were collected from blood samples, whereas RNA extracted from liver were analyzed using biochemical and statistical analysis tests. As a result, the major finding was proving that vitamin D can balance the expression of ACE1 and ACE2. Also, confirming that it can improve MetS components by elevating HDL and insulin levels while reducing the levels of BP, cholesterol, LDL, TG, GLU, ALT, AST, and IR. These outcomes may give a new insight into the RAS pathways associated with MetS.

Vitamin D Status and Potential Therapeutic Options in Critically Ill Patients: A Narrative Review of the Clinical Evidence

Vitamin D covers roles of paramount importance in the regulation of multiple physiological pathways of the organism. The metabolism of vitamin D involves kidney-liver crosstalk and requires an adequate function of these organs, where vitamin D is progressively turned into active forms. Vitamin D deficiency has been widely reported in patients living in the community, being prevalent among the most vulnerable subjects. It has been also documented in many critically ill patients upon admission to the intensive care unit. In this context, vitamin D deficiency may represent a risk factor for the development of life-threatening clinical conditions (e.g., infection and sepsis) and worse clinical outcomes. Several researchers have investigated the impact of vitamin D supplementation showing its feasibility, safety, and effectiveness, although conflicting results have put into question its real benefit in critically ill patients. The existing studies included heterogeneous critically ill populations and used slightly different protocols of vitamin D supplementation. For these reasons, pooling up the results is difficult and not conclusive. In this narrative review, we described vitamin D physiology and the pathophysiology of vitamin D depletion with a specific focus on critically ill patients with liver dysfunction, acute kidney injury, acute respiratory failure, and sepsis.

Vitamin D deficiency and cardiometabolic risk factors in adolescents: systematic review and meta-analysis

Vitamin D deficiency is associated with an increase in the occurrence of cardiometabolic events, but the evidence of this relationship in adolescence is still limited. Thus, we analyzed the association between vitamin D deficiency and cardiometabolic risk factors in adolescents. Observational studies were searching in PubMed/Medline, Embase, Scopus, Web of Science, Science Direct, Lilacs, and Google Scholar database. Random effects models were used to summarize standardized mean differences for as a summary measure. The certainty of the evidence was verified using the Cochrane recommendations. A total of 7537 studies were identified, of which 32 were included in the systematic review and 24 in the meta-analysis.Vitamin D deficiency was associated with increased systolic pressure (SMD = 0.22; 95%CI = 0.10; 0.34), diastolic pressure (SMD = 0.23; 95%CI = 0.10; 0.35), glycemia (SMD = 0.13; 95%CI = 0.05; 0.12), and insulin (SMD = 0.50; 95%CI = 0.15; 0.84), an increase in the HOMA index (SMD = 0.48; 95%CI = 0.36; 0.60), high triglyceride values (SMD = 0.30; 95%CI = 0.11; 0.49), and reduced HDL concentrations (SMD= -0.25; 95%CI = -0.46; -0.04). No statistically significant association was observed for glycated hemoglobin, LDL cholesterol, and total cholesterol. Most of the studies presented low and moderate risks of bias, respectively. The certainty of the evidence was very low for all the outcomes analyzed. Vitamin D deficiency was associated with increased exposure to the factors linked to the occurrence of cardiometabolic diseases in adolescents. Systematic Review Registration: PROSPERO (record number 42,018,086,298).

Adiposity Metabolic Consequences for Adolescent Bone Health

Infancy and adolescence are crucial periods for bone health, since they are characterized by intense physical growth and bone development. The unsatisfactory acquisition of bone mass in this phase has consequences in adult life and increases the risk of developing bone diseases at more advanced ages. Nutrient deficiencies, especially calcium and vitamin D, associated with a sedentary lifestyle; lack of sun exposure; and epigenetic aspects represent some of the main risk factors for poor bone quality. In addition, recent studies relate childhood obesity to impaired bone health; however, studies on the adiposity effects on bone health are scarce and inconclusive. Another gap concerns the implications of obesity on child sexual maturity, which can jeopardize their genetic potential bone mass and increase fracture risk. Therefore, we reviewed the analyzed factors related to bone health and their association with obesity and metabolic syndrome in adolescents. We concluded that obesity (specifically, accumulated visceral fat) harms bones in the infant–juvenile phase, thereby increasing osteopenia/osteoporosis in adults and the elderly. Thus, it becomes evident that forming and maintaining healthy eating habits is necessary during infancy and adolescence to reduce the risk of fractures caused by bone-metabolic diseases in adulthood and to promote healthy ageing.

An Analysis of the Use of the Terms Sex and Gender in Research Reported in Nursing Journals

Accurately measuring and reporting the demographic characteristics of research participants are imperative to provide consumers of research with an understanding of who was included in a study. While researchers often, incorrectly, use the variables sex and gender interchangeably, these 2 variables are different. We conducted a content analysis of 239 randomly selected research articles, with the purpose of describing how researchers have used sex and gender in studies published in nursing journals and identifying opportunities for improved clarity and precision in measuring these 2 variables. We found that significant improvement is needed in the way these variables are used/reported.

Serum Vitamin D Levels in Relation to Abdominal Obesity in Children and Adolescents: A Systematic Review and Dose-Response Meta-Analysis

Background

Findings of epidemiological studies that investigated the relationship between serum vitamin D levels and abdominal obesity were inconsistent. To evaluate the relationship between blood vitamin D levels and abdominal obesity in children and adolescents, we did a comprehensive review and dose-response meta-analysis.

Methods

A comprehensive search in electronic databases including Scopus, Web of Science (ISI), MEDLINE (Pubmed), EMBASE, and Google Scholar was conducted, up to May 2021, for epidemiological studies that investigated the linkage between serum vitamin D levels (as the exposure) and abdominal obesity (as the outcome) in children and adolescents.

Results

Combining 19 effect sizes from 14 cross-sectional studies that included 29,353 apparently healthy children illustrated that the highest vs. lowest level of serum vitamin D was related to a 35% reduced odds of abdominal obesity [odds ratio (OR): 0.65; 95% CI: 0.50, 0.84]. Linear dose-response analysis revealed that each 10 ng/ml increase in serum vitamin D levels was related to a 7% decrease in odds of abdominal obesity (OR: 0.93; 95% CI: 0.90, 0.95), only among investigations that used percentiles of waist circumference (>75th or 90th) to define the disorder (including 6,868 total subjects and 1,075 cases with abdominal obesity). Increasing serum vitamin D levels from 20 to 40 ng/ml was related to reduce odds of abdominal obesity in children.

Conclusion

A negative relationship between blood vitamin D levels and abdominal obesity in children and adolescents was discovered in this meta-analysis of epidemiologic studies. Among investigations that used waist circumference percentiles to define the disorder, the relationship was in a dose-response manner. To affirm this relationship, more research studies are needed, particularly using a prospective design.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021261319, PROSPERO 2021, identifier: CRD42021261319.

25-hydroxyvitamin D levels are inversely related to metabolic syndrome risk profile in northern Chinese subjects without vitamin D supplementation

BACKGROUND

The comparatively low 25 hydroxyvitamin D [25(OH)D] levels have been reported in patients with metabolic syndrome (MetS). Herein we investigated the cross-sectional and longitudinal relationships between serum 25(OH)D levels and MetS risk profile in northern middle-aged Chinese subjects without vitamin D supplementation.

METHODS

A cohort of 211 participants including 151 MetS patients and 60 controls at 20-69 years of age were enrolled from suburban Beijing, China. The recruited MetS patients were subjected to diet and exercise counselling for 1-year. All subjects at baseline and MetS patients after intervention underwent clinical evaluations.

RESULTS

Serum 25(OH)D levels were significantly decreased in MetS patients. 25(OH)D levels were inversely related to MetS score, fasting blood glucose (FBG) and triglyceride-glucose index (TyG) after adjusting for cofounders (all P < 0.05). Participants in the lowest tertile of 25(OH)D levels had increased odds for MetS (P = 0.045), elevated FBG (P = 0.004) in all subjects, and one MetS score gain in MetS patients (P = 0.005). Longitudinally, the metabolic statuses as well as 25(OH)D levels of MetS patients were significantly improved (all P < 0.05), and the increase of 25(OH)D levels were inversely related to MetS scores, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), FBG, and TyG, while positively related to high-density lipoprotein cholesterol (HDL-C) after adjusting for confounders.

CONCLUSIONS

25(OH)D levels were significantly decreased in MetS patients, and it was negatively associated with metabolic dysfunctions at baseline and 1-year after. Metabolic aberrations of MetS patients were significantly ameliorated with 1-year follow-up counselling accompanying by notably elevated 25(OH)D levels.

Association of vitamin D status and cardio-metabolic risk factors in children and adolescents: the CASPIAN-V study

BACKGROUND

Metabolic syndrome (MetS) starts from early life and is one of the important underlying factors for non-communicable diseases (NCDs) in adulthood. Controversial evidence exists on the role of vitamin D deficiency in increasing the risk of pediatric MetS.

OBJECTIVE

This study aimed to assess the relationship between vitamin D level with MetS and its components in children and adolescents.

METHODS

This nationwide cross-sectional study was performed as part of a surveillance program in Iran. Participants were 2596 students, aged 7 to 18 years, living in 30 provinces. In addition to filling questionnaires, a physical examination was conducted, and blood samples were collected. The serum concentration of 25-hydroxy vitamin D (25(OH)D) was measured using the direct competitive immunoassay chemiluminescence method.

RESULTS

2596 students with a mean age of 12.2 y (55.1% boys) were recruited. Prevalence of vitamin D deficiency and insufficiency in participants was 10.6% (n = 276), and 60.5% (n = 1570), respectively. The prevalence of MetS was higher in the vitamin D deficient group. Students with deficient vitamin D levels had higher odds of MetS (OR: 4.25, 95%CI: 2.26-7.98), abdominal obesity (OR: 2.24, 95%CI: 1.61-3.12), low HDL-C (OR: 1.65, 95%CI: 1.18-2.30) and high fasting blood sugar (OR: 2.56, 95%CI: 1.43-4.57) in comparison to those with sufficient level of vitamin D.

CONCLUSION

Vitamin D deficiency was associated with increased odds of MetS and its components in the Iranian pediatric population. These findings underscore the importance of prevention and control of vitamin D deficiency in preventative programs against NCDs.

Circulating serum vitamin D levels in relation to metabolic syndrome in children: A systematic review and dose-response meta-analysis of epidemiologic studies

Findings from epidemiologic studies that evaluated the relationship between serum vitamin D levels and metabolic syndrome (MetS) in children were contradictory. We conducted a systematic review and meta-analysis on the relation of serum 25(OH)D levels and MetS in children. A comprehensive search was conducted in electronic databases, up to November 2020. Eleven cross-sectional studies that reported the link between circulating vitamin D levels and MetS in children were included in the analysis. Combining 11 effect sizes from 11 cross-sectional studies with 22,196 participants revealed that highest versus lowest serum vitamin D concentration was significantly associated with a 50% reduced odds of MetS in children (OR: 0.50; 95%CI: 0.39, 0.64). Subgroup analysis by study location revealed decreased odds of MetS in both non-Asian (OR: 0.45; 95%CI: 0.33, 0.63) and Asian countries (OR: 0.54; 95%CI: 0.39, 0.76) with no heterogeneity in these subgroups. When we confined the studies to those with representative populations (n = 21,611), a significant inverse association was found between highest versus lowest circulating vitamin D level and MetS (OR: 0.55; 95%CI: 0.42, 0.71). Dose-response analysis showed that each 10 ng/ml (or 25 nmol/L) in serum vitamin D was linearly related to a 12% reduced odds of MetS (OR: 0.88; 95%CI: 0.78, 0.99) in children. A nonlinear association was also detected between serum 25(OH)D and MetS. This meta-analysis revealed that circulating vitamin D concentration was inversely associated with odds of MetS in children, in a dose-response fashion. The same finding was found in the studies with representative populations.

Prevalence of Metabolic Syndrome among Children and Adolescents in High-Income Countries: A Systematic Review and Meta-Analysis of Observational Studies

Introduction. Metabolic syndrome (MetS) is an assemblage of interconnected cardiovascular risk factors that are prevalent among children and adolescents in high-income countries (HICs). Despite the presence of several studies on the issue, the study findings are incongruent due to the absence of a gold standard diagnostic method of MetS in children. Thus, the findings of the original studies are inconclusive for policy makers and other stakeholders. This systematic review and meta-analysis is aimed at giving conclusive evidence about MetS among children and adolescents in HICs. Methods. We conducted searches using electronic databases (PubMed, Scopus, Web of Science, CINAHL (EBSCOhost), EMBASE (Elsevier), and Medline (EBSCOhost)) and other sources (Google Scholar and Google) up to September 2020. Observational studies reporting the prevalence of MetS were eligible in this study. The pooled estimates were computed in fixed and random effect models using six diagnostic methods (IDF, ATP III, de Ferranti et al., WHO, Weiss et al., and Cruz and Goran). Publication bias was verified using funnel plots and Egger’s regression tests. Subgroup and sensitivity analysis were performed in case of higher heterogeneities among the included studies. Result. In this study, 77 studies with a total population of 125,445 children and adolescents were used in the final analysis. Metabolic syndrome among the overweight and obese population was computed from 28 studies with the pooled prevalence of 25.25%, 24.47%, 39.41%, 29.52%, and 33.36% in IDF, ATP III, de Ferranti et al., WHO, and Weiss et al. criteria, respectively. Likewise, 49 studies were eligible to compute the pooled prevalence of MetS in the general population of children and adolescents. Hence, MetS was found in 3.70% (IDF), 5.40% (ATP III), 14.78% (de Ferranti et al.), 3.90% (WHO), and, 4.66% (Cruz and Goran) of study participants. Regarding the components of MetS, abdominal obesity in the overweight and obese population, and low HDL-C in the general population were the most common components. Besides, the prevalence of Mets among males was higher than females. Conclusion. This study demonstrates that MetS among children and adolescents is undoubtedly high in HICs. The prevalence of MetS is higher among males than females. Community-based social and behavioral change communications need to be designed to promote healthy eating behaviors and physical activities. Prospective cohort studies could also help to explore all possible risk factors of MetS and to design specific interventions accordingly.

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.

Vitamin D supplementation and the outcomes of critically ill adult patients: a systematic review and meta-analysis of randomized controlled trials

This meta-analysis assessed the association between vitamin D supplementation and the outcomes of critically ill adult patients. A literature search was conducted using the PubMed, Web of Science, EBSCO, Cochrane Library, Ovid MEDLINE, and Embase databases until March 21, 2020. We only included randomized controlled trials (RCTs) comparing the efficacy of vitamin D supplementation with placebo in critically ill adult patients. The primary outcome was their 28-day mortality. Overall, 9 RCTs with 1867 patients were included. In the pooled analysis of the 9 RCTs, no significant difference was observed in 28-day mortality between the vitamin D supplementation and placebo groups (20.4% vs 21.7%, OR, 0.73; 95% CI, 0.46–1.15; I² = 51%). This result did not change as per the method of vitamin D supplementation (enteral route only: 19.9% vs 18.2%, OR, 1.19; 95% CI, 0.88–1.57; I² = 10%; intramuscular or intravenous injection route: 25.6% vs 40.8%, OR, 0.48; 95% CI, 0.21–1.06; I² = 19%) or daily dose (high dose: 20.9% vs 19.8%, OR, 0.83; 95% CI, 0.51–1.36; I² = 53%; low dose: 15.6% vs 21.3%, OR, 0.74; 95% CI, 0.32–1.68; I² = 0%). No significant difference was observed between the vitamin D supplementation and placebo groups regarding the length of ICU stay (standard mean difference [SMD], − 0.30; 95% CI, − 0.61 to 0.01; I² = 60%), length of hospital stay (SMD, − 0.17; 95% CI, − 041 to 0.08; I² = 65%), and duration of mechanical ventilation (SMD, − 0.41; 95% CI, − 081 to 0.00; I² = 72%). In conclusion, this meta-analysis suggested that the administration of vitamin D did not provide additional advantages over placebo for critically ill patients. However, additional studies are needed to confirm our findings.

The Influence of Vitamin D on Neurodegeneration and Neurological Disorders: A Rationale for its Physio-pathological Actions

Vitamin D is a steroid hormone implicated in the regulation of neuronal integrity and many brain functions. Its influence, as a nutrient and a hormone, on the physiopathology of the most common neurodegenerative diseases is continuously emphasized by new studies. This review addresses what is currently known about the action of vitamin D on the nervous system and neurodegenerative diseases such as Multiple Sclerosis, Alzheimer's disease, Parkinson's disease and Amyotrophic Lateral Sclerosis. Further vitamin D research is necessary to understand how the action of this "neuroactive" steroid can help to optimize the prevention and treatment of several neurological diseases.

Serum vitamin D concentrations are inversely related to prevalence of metabolic syndrome in Qatari women

Hypovitaminosis D has reached epidemic proportions in Qatar. Vitamin D is linked to several cardiometabolic diseases such as metabolic syndrome (MetSyn), diabetes, and atherosclerosis. It is not known if vitamin D status is linked to cardiometabolic risk factors in Qatari women. Therefore, a relationship between serum 25-hydroxyvitmain D [25(OH)D] concentrations and MetSyn was investigated in Qatari women using the Qatar Biobank database. Study sample consisted of 700 women, aged 20-80 years old. A multivariate-adjusted logistic regression was used to determine relation between serum 25(OH)D and MetSyn prevalence. Multivariate linear regression was performed to determine the association between serum 25(OH)D and markers of MetSyn. Prevalences of MetSyn in the first (≈32%), second (≈27%), and third (≈28%) serum 25(OH)D quartiles were significantly higher compared to fourth serum 25(OH)D quartile (≈17.5%) (p < .035). The likelihood of having MetSyn was significantly higher in the first serum 25(OH)D quartile (OR, 1.92; 95% CI, 1.06, 3.49) compared to the fourth serum 25(OH)D quartile (p < .001) in multivariate-adjusted analysis. No relationship was observed between serum 25(OH)D and waist circumference, blood pressure, glycated hemoglobin (HbA1C), blood glucose, HDL-cholesterol, and serum triglycerides. This study showed an inverse relationship between prevalence of MetSyn and serum 25(OH)D in Qatari women. Given the widespread prevalence of vitamin D deficiency in Qatar, consideration should be given to vitamin D fortification of some selected staple foods and through targeted supplementation of vitamin D in those who are at risk for cardiometabolic diseases.

The Relationship Between Vitamin D Deficiency and Glycated Hemoglobin Levels in Patients with Type 2 Diabetes Mellitus

PURPOSE

The aims of this study were to determine the relationship between 25-hydroxyvitamin D [25(OH) D] and glycated hemoglobin (HbA1c) levels in male and female patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

The participants were adults diagnosed with T2DM recruited from Hebei General Hospital. Patient information and information regarding blood indicators were collected. The subjects were divided into no vitamin D deficiency group [25(OH) D >20 ng/mL] and vitamin D deficiency group [25(OH) D <20 ng/mL], and these groups were then further subdivided into male-only or female-only subgroups. And then, the subjects were divided into male group and female group in different 25(OH) D levels.

RESULTS

HbA1c levels in the vitamin D deficiency group were significantly higher than those in the no vitamin D deficiency group for all subjects. The same was true for female patients but not for male patients. There was no difference in HbA1c levels between male and female patients with T2DM, regardless of 25(OH) D deficiency. A negative correlation existed between 25(OH) D and HbA1c in all subjects, as well as in the male-only and female-only subgroups. Vitamin D deficiency was associated with high HbA1c levels before and after adjusting for confounding factors in all participants and in the female-only subgroup, but not in the male-only subgroup.

CONCLUSION

This study confirmed that vitamin D deficiency was related with high HbA1c levels in patients with T2DM, and this relationship differs between female and male patients.

Does Weekend Catch-up Sleep Affect High-Sensitivity C-Reactive Protein Levels Among Korean Workers?: A Cross-Sectional Study Using KNHANES

OBJECTIVE

We sought to determine whether weekend catch-up sleep (CUS) influenced serum high-sensitivity C-reactive protein (hs-CRP) levels in workers.

METHODS

We analyzed the Korean National Health and Nutrition Examination Survey (2016) data from 3304 workers. Univariate and multivariate logistic regression analyses were used to calculate odds ratios and 95% confidence intervals based on serum hs-CRP cut-off values of 1.0 and 3.0 mg/L, respectively.

RESULTS

We found that at least 1-hour and less than 2 hours of weekend CUS reduced the risk of elevated hs-CRP levels (odds ratio 0.80, 95% confidence interval 0.64 to 0.99) in multivariate logistic regression analysis.

CONCLUSION

CUS may reduce serum hs-CRP levels in workers, thereby reducing the risk of cardiovascular disease.

Serum 25-hydroxyvitamin D is associated with obesity and metabolic parameters in US children

OBJECTIVE

To explore the relationships of serum 25-hydroxyvitamin D (25(OH)D) with obesity and metabolic parameters in US children.

DESIGN

Cross-sectional analysis. We evaluated the associations between serum 25(OH)D and multiple measurements of adiposity, serum lipid concentrations, fasting glucose and insulin resistance in children aged 6-18 years with adjustments for multiple covariates.

SETTING

The National Health and Nutrition Examination Survey, 2001-2006.

PARTICIPANTS

A nationally representative sample of 6311 children and adolescents aged 6-18 years.

RESULTS

Among US children and adolescents, the prevalence of vitamin D deficiency has been especially high in older children, girls and the non-Hispanic Black population. Higher odds of obesity were found at a 25(OH)D concentration of <30 nmol/l (deficiency) than at >50 nmol/l under both criteria for obesity in children (OR = 3·27, Ptrend ≤ 0.001). Moreover, increased odds of having abnormal HDL-cholesterol (OR = 1·71, Ptrend ≤ 0.001) and impaired insulin resistance (OR = 4·15, Ptrend ≤ 0·001) were found for children deficient in 25(OH)D compared with those with normal 25(OH)D concentrations. When the children and adolescents were stratified by gender, we found stronger associations between serum 25(OH)D concentration and both HDL-cholesterol and insulin resistance in girls. No association of 25(OH)D with any other metabolic parameter was found.

CONCLUSIONS

Our results suggest a potential harmful association between low serum 25(OH)D concentration and the risk of obesity among children. However, the underlying mechanisms require further investigation.

The GC2 haplotype of the vitamin D binding protein is a risk factor for a low plasma 25-hydroxyvitamin D concentration in a Han Chinese population

Background

The GC haplotype of the vitamin D binding protein (encoded by the GC gene) might be a risk factor to the vitamin D (VD) nutritional status for many populations, while evidences from the Chinese Han population are sparse. We test the association between vitamin D binding protein genotypes and VD status as well as the metabolic parameters of glucose and lipids in a Han Chinese population.

Methods

In a cross-sectional study conducted at a health examination centre (registered in ClinicalTrials.gov as QLS2013), 2641 adults were included and grouped according to their plasma 25-hydroxyvitamin D (25OHD) concentrations as VD deficient (VDD), insufficient (VDI), or sufficient (VDS). The rs7041 and rs4588 genotypes were analysed with a molecular beacon-based qPCR method using blood samples.

Results

Plasma 25OHD concentrations were lower in the GC2/2, rs7041T/T, and rs4588A/A genotypes than the GC1f/1s, rs7041G/T, and rs4588C/C genotypes (P <  0.05). After adjusting for confounders, the GC2 haplotype increased the risk of low VD status (P <  0.05) in both genders. More genotypic models revealed the negative contributions of rs4588A than rs7041T to low VD status (P <  0.05). The combined rates of VDD and VDI were 80.2% in males and 86.1% in females. Compared with VDI, VDS, or both, VDD showed higher plasma concentrations of fasting blood glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides in males (P <  0.05); however, no significant differences were found with regard to these parameters between the subgroups defined by the GC genotypes (P > 0.05).

Conclusions

In a Han Chinese population, the GC2 haplotype or more exactly rs4588A is a risk factor for low VD status but is not associated with glucose and lipid metabolic disorders, which are inversely correlated with the circulating 25OHD concentration in males.

Trial registration

The study was retrospectively registered in January 2018 as NCT03406234 in the ClinicalTrials.gov online system.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0332-0) contains supplementary material, which is available to authorized users.

Factors Associated with Vitamin D Status Among Korean Female Adolescents

PURPOSE

The prevalence of vitamin D deficiency among female adolescents in South Korea is the highest in East Asia. Therefore, this study aims to identify factors associated with vitamin D status among female adolescents in South Korea.

DESIGN AND METHODS

This cross-sectional descriptive study was conducted using a data set from the fifth Korean National Health and Nutrition Examination Survey (2010-2012). Participants comprised 734 female adolescents aged 12-18 years. A general linear model using a complex samples design was employed.

RESULTS

The mean vitamin D level of the participants was 14.90 ng/mL. Among these participants, 87.6% had a vitamin D deficiency. As their age increased by one year, their vitamin D level decreased by 0.47 ng/mL. Female adolescents with a low household income had vitamin D levels lower by 1.88 ng/mL than those with a high household income. Vitamin D levels in female adolescents who skipped lunch was lower by 3.41 ng/mL than those who had lunch.

CONCLUSION

The prevalence of vitamin D deficiency among female adolescents in South Korea is considerable. The findings suggest that age, socioeconomic status, and skipping a meal were associated with vitamin D status in female adolescents, but physical activity was not.

PRACTICE IMPLICATIONS

As the findings of this study indicate, older female adolescents and those from lower household incomes may be at higher risk for lower levels of Vitamin D. Counseling female adolescents as to dietary measures to avoid vitamin D deficiency is advised. Preventive health for at risk female adolescents includes provision of health education and counseling.

Nutrients in Fish and Possible Associations with Cardiovascular Disease Risk Factors in Metabolic Syndrome

Non-communicable diseases (NSDs) are responsible for two-thirds of all deaths globally, whereas cardiovascular disease (CVD) alone counts for nearly half of them. To reduce the impact of CVD, targeting modifiable risk factors comprised in metabolic syndrome (e.g., waist circumference, lipid profile, blood pressure, and blood glucose) is of great importance. Beneficial effects of fish consumption on CVD has been revealed over the past decades, and some studies suggest that fish consumption may have a protective role in preventing metabolic syndrome. Fish contains a variety of nutrients that may contribute to health benefits. This review examines current recommendations for fish intake as a source of various nutrients (proteins, n-3 fatty acids, vitamin D, iodine, selenium, and taurine), and their effects on metabolic syndrome and the CVD risk factors. Fatty fish is recommended due to its high levels of n-3 fatty acids, however lean fish also contains nutrients that may be beneficial in the prevention of CVD.