Plasma vitamin D and parathormone are associated with obesity and atherogenic dyslipidemia: a cross-sectional study

Vitamin D and Dyslipidemia: Is There Really a Link? A Narrative Review

Nowadays, the interest in the extraskeletal effects of vitamin D is growing. In the literature, its several possible actions have been confirmed. Vitamin D seems to have a regulatory role in many different fields-inflammation, immunity, and the endocrine system-and many studies would demonstrate a possible correlation between vitamin D and cardiovascular disease. In this paper, we deepened the relationship between vitamin D and dyslipidemia by reviewing the available literature. The results are not entirely clear-cut: on the one hand, numerous observational studies suggest a link between higher serum vitamin D levels and a beneficial lipid profile, while on the other hand, interventional studies do not demonstrate a significant effect. Understanding the possible relationship between vitamin D and dyslipidemia may represent a turning point: another link between vitamin D and the cardiovascular system.

Long Short-Term Memory-Based Multiomics Reveal Lactobacillus casei-Derived Postbiotics Inhibiting Lipids Digestion via Mediating the Upregulation of α-Helices in Lipase

SCOPE

The antiobesity function of probiotics has been declared, while the application in high-risk patients and coding side effect has focused attention to postbiotics. This investigation profiles the mechanism of postbiotics affecting lipid digestion at molecular level, and establishes a momentous foundation for the clinical application of postbiotics in obesity suppression.

METHODS AND RESULTS

An operational framework for butter digestion is constructed to collect the digests in the intestine at 0, 40, 80, and 120 min with various postbiotics supplement. A total of 227 lipids and 414 metabolites are detected by pseudo-targeted lipidomics integrated with the long short-term memory-based metabolomics, and the triacylglycerol (TG, from 134.1 to 184.7 mg kg-1 ) and diacylglycerol (DG, from 4.2 to 8.4 mg kg-1 ) are identified as significantly different lipids with or without postbiotics supplement. A total of eight substances related to the inhibition of gastric lipase and pancreatic lipase are screened through the molecular simulation computation in silicon and enzymatic reaction kinetics, and thus curtailing the bioaccessibility of lipids.

CONCLUSIONS

Lactobacillus casei JCM1134-derived postbiotics propel the structure of lipase to aggregate by increasing the α-helix, and thus hampering the digestion of triglycerides through noncompetitive inhibition.

Vitamin D Deficiency Is Associated with Impaired Sensitivity to Thyroid Hormones in Euthyroid Adults

The relationship between vitamin D deficiency and sensitivity to thyroid hormones was unclear. We aimed to explore the association of 25-hydroxyvitamin D (25(OH)D) levels with thyroid hormone sensitivity in euthyroid adults. A total of 3143 subjects were included. The serum 25(OH)D, free thyroxine (FT3), free thyrotropin (FT4), thyroid-stimulating hormone (TSH), and other clinical variables were measured. Vitamin D deficiency was defined as 25(OH)D < 20 ng/mL. Thyroid feedback quantile-based index (TFQI), parametric thyroid feedback quantile-based index (PTFQI), thyroid-stimulating hormone index (TSHI), thyrotrophic thyroxine resistance index (TT4RI), and FT3/FT4 were calculated to assess thyroid hormone sensitivity. Results showed that 58.8% of the participants had vitamin D deficiency. They had significantly higher levels of triglyceride, insulin, FT3, FT4, TSH, TFQI, PTFQI, TSHI, and TT4RI and lower levels of high-density lipoprotein cholesterol than those with sufficient vitamin D (all p < 0.05). Logistic regression analysis showed that the risk of impaired sensitivity to thyroid hormones evaluated by TFIQ, PTFQI, TSHI, and TT4RI increased by 68% (OR: 1.68; 95%CI: 1.45-1.95; and p < 0.001), 70% (OR: 1.70; 95%CI: 1.46-1.97; and p < 0.001), 66% (OR: 1.66; 95%CI: 1.43-1.92; and p < 0.001), and 50% (OR: 1.50; 95%CI: 1.30-1.74; and p < 0.001), respectively, in participants with vitamin D deficiency compared with those with sufficient vitamin D after adjusting for multiple confounders. In conclusion, in euthyroid populations, vitamin D deficiency was associated with impaired sensitivity to thyroid hormones.

Lactobacillus casei-derived postbiotics inhibited digestion of triglycerides, glycerol phospholipids and sterol lipids via allosteric regulation of BSSL, PTL and PLA2 to prevent obesity: perspectives on deep learning integrated multi-omics

The anti-obesity potential of probiotics has been widely reported, however their utilization in high-risk patients and potential adverse reactions have led researchers to focus their attention on postbiotics. Herein, pseudo-targeted lipidomics linked with deep learning-based metabolomics was utilized to dynamically characterize the postbiotic potential of heat-inactivated Lactobacillus casei JCM1134 supplementation after a high-fat diet in treating obesity. MG (ranged from 423.0 ± 1.4 mg L-1 to 331.45 ± 2.3 mg L-1), LPC (ranged from 13.1 ± 0.08 mg L-1 to 10.2 ± 0.1 mg L-1) and Cho (ranged from 9.0 ± 0.3 mg L-1 to 5.7 ± 0.2 mg L-1) in intestinal digestive products were significantly decreased, indicating that the digestion of lipid was inhibited. 8-C-glucosylorobol, from Lactobacillus casei, was confirmed from quantitative results and molecular simulation calculations to inhibit the transformation of TG, DG, and ChE through weakening hydrogen bonds between enzymes and substrates and reducing the binding energy. Pristimerin and 2,4-quinolinediol can effectively reduce the hydrogen bonding force between PC and phospholipase A2, which were related to the obstruction of phosphatidylcholine digestion. This research deepened the understanding of the mechanism underlying the inactivated probiotics affecting lipid digestion, establishing the critical groundwork for clinical application of probiotics in inhibiting obesity.

The role of vitamin D in menopausal women's health

Vitamin D (VD) is known to play an important role in the maintenance of calcium homeostasis and bone metabolism. In recent years, there has also been a growing interest in Vitamin D for health issues beyond the bones. Menopausal women are at risk of reduced bone density and increased risk of fracture due to a decline in estrogen levels. There is also an increased risk of cardiovascular disease, diabetes and hyperlipidaemia due to impaired lipid metabolism. The menopausal and emotional symptoms due to menopause are also increasingly prominent. This article summarizes the role of Vitamin D in menopausal women's health, including the effects of Vitamin D on skeletal muscle, cardiovascular disease, Genitourinary Syndrome of Menopause (GSM), cancer and emotional symptoms. Vitamin D regulates the growth of vaginal epithelial cells and alleviates genitourinary tract problems in menopausal women. Vitamin D also modulates immune function and influences the production of adipokines. Vitamin D and its metabolites also have an anti-proliferative effect on tumour cells. This narrative review, by summarizing recent work on the role of Vitamin D in menopausal women and in animal models of menopause, aims to provide a basis for further development of the role of Vitamin D in the health of menopausal women.

Calcium carbonate-enriched pumpkin affects calcium status in ovariectomized rats

Calcium carbonate (CaCO₃)-enriched pumpkin may serve as a good source of calcium for patients diagnosed with osteoporosis. In this study, we aimed to determine the effect of CaCO₃-enriched pumpkin on Ca status in ovariectomized rats. The study included 40 female Wistar rats divided into five groups (n = 8). One group was fed with a standard diet (control group), while the other four groups were ovariectomized and received a standard diet (control ovariectomized group), or a diet containing CaCO₃-enriched pumpkin, alendronate, or both. The nutritional intervention lasted 12 weeks, and then the rats were euthanized. Tissue and blood samples were collected and assessed for the levels of total Ca, estradiol, parathyroid hormone, and procollagen type I N propeptide. In addition, a histological analysis was performed on femurs. The results of the study suggest that CaCO₃-enriched pumpkin can increase Ca content in femurs and improve bone recovery in ovariectomized rats. Furthermore, enriched pumpkin contributes to Ca accumulation in the kidneys, and this effect is more pronounced in combination with alendronate.

Atherogenic Index of Plasma (AIP) and Its Association with Fatty Liver in Obese Adolescents

BACKGROUND

The atherogenic index of plasma (AIP) is the base-10 logarithmic conversion of the triglyceride to high-density lipoprotein cholesterol ratio [AIP = log10 (triglyceride/HDL cholesterol)]. Some studies have found a link between low serum vitamin D levels, AIP, and fatty liver. This study was conducted to evaluate the relationship between AIP levels, fatty liver, and vitamin D levels in obese adolescents aged 10-17 years.

METHODS

This study included 136 adolescents, including 83 obese and 53 healthy controls, in the age range of 10-17 years. Thirty-nine of the obese adolescents had fatty livers. Those with ultrasonography grades 2 or 3 of fat were in the fatty liver group. The AIP value was calculated as the logarithmic conversion of the ratio (triglyceride/HDL cholesterol) at the base of 10. Vitamin D and other laboratory tests were analyzed biochemically. Statistical evaluations were made with the SPSS program.

RESULTS

The AIP, body mass index (BMI), homeostatic model assessment for insulin resistance (HOMA-IR), and insulin averages of obese adolescents with fatty liver were significantly higher than those of obese adolescents without fatty liver and the healthy control group (p < 0.05). Again, the mean AIP of obese patients without fatty liver was pointedly higher than that of the healthy control group (p < 0.05). There was a positive, moderate relationship between AIP and BMI, AIP and HOMA-IR, and AIP and insulin levels (p < 0.05), whereas there was a negative, moderate (37.3%) relationship between AIP and vitamin D (p = 0.019).

CONCLUSION

AIP levels were higher in obese adolescents, and this increase was higher in obese adolescents with fatty liver in this study. Moreover, we detected a negative correlation between AIP and vitamin D levels and a positive correlation with BMI, insulin resistance, and insulin levels. Based on our data, we concluded that AIP can be a useful predictor of fatty liver in obese adolescents.

Identification of Biomarkers Related to Metabolically Unhealthy Obesity in Korean Obese Adolescents: A Cross-Sectional Study

BACKGROUND

The current study aimed to screen for relationships and different potential metabolic biomarkers involved between metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) in adolescents.

METHODS

The study included 148 obese adolescents aged between 14 and 16. The study participants were divided into MUO and MHO groups based on the age-specific adolescent metabolic syndrome (MetS) criteria of the International Diabetes Federation. The current study was conducted to investigate the clinical and metabolic differences between the MHO and MUO groups. Multivariate analyses were conducted to investigate the metabolites as independent predictors for the odds ratio and the presence of the MetS.

RESULTS

There were significant differences in the three acylcarnitines, five amino acids, glutamine/glutamate ratio, three biogenic amines, two glycerophospholipids, and the triglyceride-glucose index between the MUO group and those in the MHO group. Moreover, several metabolites were associated with the prevalence of MUO. Additionally, several metabolites were inversely correlated with MHO in the MUO group.

CONCLUSIONS

In this study, the biomarkers found in this study have the potential to reflect the clinical outcomes of the MUO group. These biomarkers will lead to a better understanding of MetS in obese adolescents.

Serum 25-hydroxyvitamin D levels and dyslipidemia: a systematic review and dose-response meta-analysis of epidemiologic studies

CONTEXT

Findings of previous observational studies that examined the association between circulating vitamin D levels and lipid profiles have been inconsistent.

OBJECTIVE

A dose-response meta-analysis of epidemiologic studies was conducted to investigate the relationship between serum 25-hydroxyvitamin D levels and dyslipidemia in adults.

DATA SOURCES

Electronic databases were searched systematically for articles published up to June 2021.

DATA EXTRACTION

Fifty-seven observational studies and 2 cohort studies that reported odds ratios (ORs) or relative risks (RRs) with 95%CIs for dyslipidemia in relation to serum 25-hydroxyvitamin D levels in adults were included.

DATA ANALYSIS

A high level, vs a low level, of serum 25-hydroxyvitamin D was related to a significant 19% decrease in the odds of hypertriglyceridemia (OR 0.81; 95%CI, 0.74-0.89), an 18% reduction in low high-density lipoprotein cholesterol (HDL-C) (OR 0.82; 95%CI, 0.76-0.89), and an 18% reduction in dyslipidemia (OR 0.82; 95%CI, 0.75-0.91). No significant association was found between a high vs a low level of serum 25-hydroxyvitamin D and risk of high low-density lipoprotein cholesterol (LDL-C) levels (OR 0.86; 95%CI, 0.62-1.19) or hypercholesterolemia (OR 1.03; 95%CI, 0.93-1.15). Dose-response analyses demonstrated that each 10 ng/mL increase in the serum 25-hydroxyvitamin D level was linked, respectively, to a 7% (OR 0.93;95%CI, 0.85-1.02), a 3% (OR 0.97; 95%CI, 0.90-1.05), and a 4% (OR 0.96; 95%CI, 0.92-1.00) marginally significant decrease in the odds of hypertriglyceridemia, low HDL-C, and dyslipidemia.

CONCLUSION

Higher serum 25-hydroxyvitamin D levels are associated with significant reductions in the odds of hypertriglyceridemia, low HDL-C, and dyslipidemia in a dose-response trend.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021219484.

PCOS Physiopathology and Vitamin D Deficiency: Biological Insights and Perspectives for Treatment

Recent literature has stressed the importance of vitamin D (VD) in polycystic ovary syndrome (PCOS). Women with PCOS are deficient in VD, particularly those with a higher weight. Hypovitaminosis is a risk factor for glucose intolerance, and reduced levels of VD is associated with insulin resistance and increased diabetes risk. Since women with PCOS and hirsutism seem to have lower levels of VD than women with PCOS without hirsutism, a correlation between VD deficiency and hyperandrogenism may be suggested. Interestingly, VD is crucial for many human physiological functions, including to counteract inflammation and oxidative stress. Some studies evaluated effects of VD supplementation on glucose homeostasis variables, hormonal status, lipid concentrations, and biomarkers of inflammation and oxidative stress among VD-deficient women. Moreover, VD has been shown to play a role in egg quality and fertility. This review aims to show the relationship between VD and the endocrine and metabolic profile of PCOS patients, as well as its implications for their fertility. The supplement of VD to the common therapy can lead to an improvement of the insulin resistance and lipid metabolism, a reduction of circulating androgens, as well as a better response to the induction of ovulation in PCOS women.

Secondary Hyperparathyroidism Before and After Bariatric Surgery: a Prospective Study with 2-Year Follow-Up

PURPOSE

Secondary hyperparathyroidism (SHPT) is linked to obesity. Bariatric surgery may be associated with calcium and vitamin D deficiencies leading to SHPT. This study aimed to detect the prevalence of SHPT before and after bariatric surgery.

METHODS

This prospective study assessed the prevalence of SHPT after sleeve gastrectomy (SG, n = 38) compared to one-anastomosis gastric bypass (OAGB, n = 86). All patients were followed up for 2 years. Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry.

RESULTS

Of the 124 patients, 71 (57.3%) were females, and 53 (42.7%) were males, with a mean age of 37.5 ± 8.8 years. Before surgery, 23 patients (18.5%) suffered from SHPT, and 40 (32.3%) had vitamin D deficiency. The prevalence of SHPT increased to 29.8% after 1 year and 36.3% after 2 years. SHPT was associated with lower levels of vitamin D and calcium and higher reduction of BMD in the hip but not in the spine. After 2 years, SHPT was associated with a significantly lower T-score in the hip. SHPT and vitamin D deficiency were significantly more common in patients subjected to OAGB compared to SG (p = 0.003, and p < 0.001, respectively). There is a strong negative correlation between vitamin D levels and parathormone levels before and after surgery.

CONCLUSION

Prevalence of SHPT is high in obese patients seeking bariatric surgery, especially with lower vitamin D levels. Bariatric surgery increases the prevalence of SHPT up to 2 years. Gastric bypass is associated with a higher risk of developing SHPT compared to SG.

Environmental Factors That Affect Parathyroid Hormone and Calcitonin Levels

Calciotropic hormones, parathyroid hormone (PTH) and calcitonin are involved in the regulation of bone mineral metabolism and maintenance of calcium and phosphate homeostasis in the body. Therefore, an understanding of environmental and genetic factors influencing PTH and calcitonin levels is crucial. Genetic factors are estimated to account for 60% of variations in PTH levels, while the genetic background of interindividual calcitonin variations has not yet been studied. In this review, we analyzed the literature discussing the influence of environmental factors (lifestyle factors and pollutants) on PTH and calcitonin levels. Among lifestyle factors, smoking, body mass index (BMI), diet, alcohol, and exercise were analyzed; among pollutants, heavy metals and chemicals were analyzed. Lifestyle factors that showed the clearest association with PTH levels were smoking, BMI, exercise, and micronutrients taken from the diet (vitamin D and calcium). Smoking, vitamin D, and calcium intake led to a decrease in PTH levels, while higher BMI and exercise led to an increase in PTH levels. In terms of pollutants, exposure to cadmium led to a decrease in PTH levels, while exposure to lead increased PTH levels. Several studies have investigated the effect of chemicals on PTH levels in humans. Compared to PTH studies, a smaller number of studies analyzed the influence of environmental factors on calcitonin levels, which gives great variability in results. Only a few studies have analyzed the influence of pollutants on calcitonin levels in humans. The lifestyle factor with the clearest relationship with calcitonin was smoking (smokers had increased calcitonin levels). Given the importance of PTH and calcitonin in maintaining calcium and phosphate homeostasis and bone mineral metabolism, additional studies on the influence of environmental factors that could affect PTH and calcitonin levels are crucial.

Vitamin D is associated with the hypertriglyceridemic waist phenotype in Brazilian children

BACKGROUND

Prevalence of cardiometabolic risk factors is increasing and vitamin D insufficiency/deficiency has become a worldwide public health problem, even in tropical countries. Therefore, we identified the prevalence of hypertriglyceridemic waist phenotype (HWP) and evaluate its relationship with vitamin D insufficiency/deficiency.

METHODS

A cross-sectional study with 378 children aged 8 and 9 enrolled in all urban schools in the city of Viçosa, MG, Brazil. Anthropometric measurements, body composition (dual energy X-ray absorptiometry), biochemical tests and clinical evaluation were performed. Poisson regression was used to analyze the association between vitamin D and HWP.

RESULTS

Prevalence of HWP was 16.4%. This prevalence was higher among children with vitamin D insufficiency and deficiency and in those with a greater number of other cardiometabolic risk factors. Multiple regression analysis showed that children with vitamin D insufficiency and deficiency had, respectively, prevalence 85% (95% CI: 1.03-3.30) and 121% (95% CI: 1.11-4.45) higher of HWP than the vitamin D sufficiency group.

CONCLUSION

Vitamin D insuffiency and deficiency were associated with a higher prevalence of HWP among children, regardless of the presence of other cardiometabolic risk factors, indicating an additional risk of inadequate vitamin D status to cardiometabolic health in childhood.

Combined associations of 25-hydroxivitamin D and parathyroid hormone with diabetes risk and associated comorbidities among U.S. white and black women

Background/objectives

There is evidence of black–white differences in vitamin D status and cardiometabolic health. This study aimed to further evaluate the joint associations of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) with risks of diabetes and related cardiometabolic comorbidities among white and black women.

Subjects/methods

We cross-sectionally and prospectively analyzed data from 1850 black and 3000 white postmenopausal women without cardiovascular disease or dialysis at baseline from the Women’s Health Initiative—Observational Study. Weighted Cox proportional hazards analyses and weighted logistic regression models were used to examine the joint associations of 25(OH)D and PTH with incident diabetes and prevalence of other diabetes-related cardiometabolic comorbidities (including CKD, hypertension, or obesity).

Results

We identified 3322 cases of obesity (n = 1629), hypertension (n = 2759), or CKD (n = 318) at baseline and 453 incident cases of diabetes during 11 years of follow-up. Cross-sectionally, lower 25(OH)D and higher PTH were independently associated with higher prevalence of hypertension [odds ratio (OR) = 0.79; 95% confidence interval (CI): 0.72–0.87 and OR = 1.55; 95% CI: 1.39–1.73] among white women only. When stratified by diabetes status, compared to women with 25(OH)D ≥50 nmol/L and PTH ≤6.89 pmol/L (65 pg/mL), women who did not have diabetes with vitamin D deficiency (<50 nmol/L) and PTH excess (>6.89 pmol/L) had higher prevalence of CKD, hypertension, or obesity (OR = 4.23; 95% CI: 2.90–6.18) than women who had diabetes (OR = 1.89; 95% CI: 0.96–3.71). Prospectively, lower 25(OH)D was associated with lower diabetes incidence [hazard ratio (HR) = 0.73; 95% CI: 0.62–0.86] in white women. Jointly, compared to the group with 25(OH)D ≥50 nmol/L and PTH ≤6.89 pmol/L, white women with 25(OH)D deficiency (<50 nmol/L) had elevated risk for diabetes, regardless of PTH levels.

Conclusions

Low 25(OH)D and high PTH were jointly associated with increased risk of diabetes among white women only. Their joint associations with high prevalence of CKD, hypertension, and obesity were more pronounced among women without diabetes.

Patterns of Calcium- and Chloride-Ion Disorders and Predictors among Obese Outpatient Adults in Southern Ethiopia

BACKGROUND

Obesity is a condition characterized by abnormal or excess accumulation of fat in body tissue, which may impair health and result in electrolyte derangement. Hypercalcemia and hypochloremia are significant problems in obese patients, and can cause substantial morbidity and mortality. Determination of patterns of calcium and chloride may play a major role in the management of obese patients. Therefore, this study aimed to determine calcium and chloride disorders and their predictors among obese adults in the outpatient department at Wolkite University Specialized Hospital, southern Ethiopia from May to August 2020.

METHODS

This institution-based cross-sectional study was conducted on 250 obese adults attending the outpatient department from May to August 2020. Structured questionnaires through face-to-face interviews and participants' medical records were used to collect information on determinants related to calcium- and chloride-ion disturbances. Levels of serum calcium and chloride were measured using an ion-selective electrode analyzer. Bivariate and multivariate logistic regression analyses were done to identify determinants associated with calcium and chloride disorders. Using ORs and 95% CIs,P<0.05 was considered significant.

RESULTS

Among the 250 patients, 18% (95% CI 53.02-111) and 17.6% (95% CI 0.78-12) of study participants were hypochloremic and hypercalcemic, respectively. Age ≥50 years (AOR 3.58, 95% CI 2.57-11.10), diuretic use (AOR 2.35, 95% CI 1.31-4.23), and obesity (AOR, 6.82, 95% CI 2.26-14.62) were independent predictors of hypochloremia on multivariate logistic regression, and obesity (AOR 9.21, 95% CI 2.50-14.81), overweight (AOR 8.32, 95% CI 1.61-10.20) and physical inactivity (AOR 4.28, 95% CI 1.71-10.44) were predictors of hypercalcemia.

CONCLUSION

High burdens of hypochloremia (18%) and hypercalcemia (17.6%) were observed in these patients. Increased age, diuretic use, being overweight, and physical inactivity were predictors of electrolyte disorders. The findings of this study should be taken into consideration to implement preventive interventions on these predictors in obese patients. Promoting sufficient fruit and vegetable consumption and physical exercise and determination of serum-chloride and -calcium levels in adult overweight/obese patients are recommended to minimize the emergence of electrolyte disorders.

The interplay of vitamin D and body mass index in acne patients vs. controls

BACKGROUND

Acne vulgaris is a disease of pilosebaceous units and manifests with polymorphic lesions. Vitamin D acts at various stages in its pathogenesis. Recently, vitamin D and metabolic syndrome have shown to be associated with acne vulgaris and its severity.

AIMS

To see the effects of serum 25(OH)D3 levels and body mass index on acne vulgaris and their correlation with the severity of acne.

PATIENTS/METHODS

Fifty patients of acne vulgaris and thirty age- and sex-matched healthy volunteers were recruited. Global Acne Grading System was used to grade the acne severity. Body mass index of all patients and control group was calculated, and serum levels of 25(OH)D3 were measured using chemiluminescence immunoassay.

RESULTS

Vitamin D deficiency was detected in 28% of patients with acne but only in 6.7% of the healthy controls (p value 0.022). However, there was no significant difference in mean serum 25(OH)D levels in acne patients and controls. Vitamin D deficiency was seen in 60% of the very severe and 33% of the severe acne cases. Eighty percent of patients with very severe acne and 73.33% of severe acne patients had high body mass index. The relationship between severity of acne and body mass index was statistically significant.

CONCLUSION

Vitamin D deficiency was more prevalent in acne, and with the increase in severity of acne, an inverse relation between serum levels of vitamin D and body mass index was seen, but statistically significant relation was found only in the very severe cases of acne vulgaris.

Update on the Crosstalk Between Adipose Tissue and Mineral Balance in General Population and Chronic Kidney Disease

Adipose tissue is nowadays considered as a major endocrine organ, which apart from controlling lipid metabolism, displays a significant role in energy expenditure, food intake and in the regulation of various systemic physiological processes. Adipose derived pro-inflammatory cytokines and adipokines, particularly leptin and adiponectin, provide inter-communication of adipose tissue with various metabolic pathways, ultimately resulting in a complex network of interconnected organ systems. Recent clinical and experimental research has been focused on exploring the direct interaction between adipokine profile and elements of mineral metabolism, including parathormone (PTH), fibroblast growth factor-23 (FGF23) and calcitriol. The emerging crosstalk between adipose tissue and calcium and phosphorus homeostasis suggests that metabolic disorders from one system may directly affect the other and vice versa. It is current knowledge that fat metabolism disturbance, commonly encountered in obese individuals, influences the expression of calciotriopic hormones in general population, while various clinical trials attempting to successfully achieve body fat loss by modulating mineral profile have been published. In chronic kidney disease (CKD) state, there is an increasing evidence suggesting that mineral disorders, influence adipose tissue and linked endocrine function. On the contrary, the impact of disturbed fat metabolism on CKD related mineral disorders has been also evocated in clinical studies. Recognizing the pathogenetic mechanisms of communication between adipose tissue and mineral balance is critical for understanding the effects of metabolic perturbations from the one system to the other and for identifying possible therapeutic targets in case of disrupted homeostasis in one of the two connected systems. To that end, this review aims to enlighten the recent advances regarding the interplay between mineral metabolism, fat mass and adipokine profile, based on in vitro, in vivo and clinical studies, in general population and in the course of CKD.

Association of 25-hydroxyvitamin D levels and metabolic syndrome in Thai postmenopausal women

BACKGROUND AND AIMS

Low serum 25-hydroxyvitamin D [25(OH)D] levels have been reported to be associated with metabolic syndrome (MetS). In this study, we aimed to investigate the association between serum 25(OH)D levels and MetS in Thai postmenopausal women.

METHODS

A total of 340 postmenopausal women were enrolled in the study. The concentration of 25(OH)D, lipid profiles, fasting blood glucose (FBG) levels, blood pressure, and demographic and anthropometric parameters were measured. Subjects were divided into the hypovitaminosis D and vitamin D sufficiency groups. The association of serum 25(OH)D levels with MetS in postmenopausal women was analyzed using multivariate regression analysis.

RESULTS

Waist circumference, total cholesterol levels, and triglyceride levels were significantly higher in hypovitaminosis D than in vitamin D sufficiency (p < 0.05). The prevalence of MetS, central obesity, and hypertriglyceridemia in hypovitaminosis D was significantly higher than in vitamin D sufficiency (p < 0.05). In the multivariable logistic regression model, hypovitaminosis D was associated with MetS (OR 1.85; 95% CI 1.12-3.04, p = 0.015), central obesity (OR 2.41; 95% CI 1.20-4.85, p = 0.014), and hypertriglyceridemia (OR 1.91; 95% CI 1.12-3.26, p = 0.018) compared with vitamin D sufficiency after adjusting for covariates. Serum vitamin D concentrations were significantly lower in the MetS group than in the non-MetS group (p = 0.016) and decreased with an increasing number of MetS components (p for trend = 0.034).

CONCLUSIONS

Hypovitaminosis D was associated with an increased risk of MetS, central obesity, and hypertriglyceridemia in Thai postmenopausal women.

Circulating calcium levels and the risk of type 2 diabetes: a systematic review and meta-analysis

Abnormal Ca homeostasis has been associated with impaired glucose metabolism. However, the epidemiological evidence is controversial. We aimed to assess the association between circulating Ca levels and the risk of type 2 diabetes mellitus (T2DM) or abnormal glucose homeostasis through conducting a systematic review and meta-analysis. Eligible studies were identified by searching electronic database (PubMed, Embase and Google Scholar) and related references with de novo results from primary studies up to December 2018. A random-effects meta-analysis was performed to estimate the weighted relative risks (RR) and 95 % CI for the associations. The search yielded twenty eligible publications with eight cohort studies identified for the meta-analysis, which included a total of 89 165 participants. Comparing the highest with the lowest category of albumin-adjusted serum Ca, the pooled RR was 1·14 (95 % CI 1·05, 1·24) for T2DM (n 51 489). Similarly, serum total Ca was associated with incident T2DM (RR 1·25; 95 % CI 1·10, 1·42) (n 64 502). Additionally, the adjusted RR for 1 mg/dl increments in albumin-adjusted serum Ca or serum total Ca levels was 1·16 (95 % CI 1·07, 1·27) and 1·19 (95 % CI 1·11, 1·28), respectively. The observed associations remained with the inclusion of a cohort study with ionised Ca as the exposure. However, data pooled from neither case-control (n 4) nor cross-sectional (n 8) studies manifested a significant correlation between circulating Ca and glucose homeostasis. In conclusion, accumulated data from the cohort studies suggest that higher circulating Ca levels are associated with an augmented risk of T2DM.

Vitamin D status and cardiometabolic risk factors in Greek adolescents with obesity - the effect of vitamin D supplementation: a pilot study

Introduction

Obesity is associated with cardiovascular disease (CVD) risk factors as well as decreased 25(OH) vitamin D serum levels. We aimed to study 25(OH) vitamin D levels in adolescents with obesity compared with normal weight controls in association with CVD risk factors, and the possible effect of vitamin D supplementation.

Material and methods

In a cross-sectional study, 69 obese and 34 normal-weight adolescents were included. In an interventional study 15 adolescents with obesity and vitamin D insufficiency were given 2000 IU vitamin D per os daily for 3 months.

Results

Adolescents with obesity had significantly lower 25(OH) vitamin D levels compared with normal-weight controls (12.0 (3.0–36.0) vs. 34.0 (10.0–69.0) ng/ml, respectively, p < 0.001). In adolescents with obesity, 25(OH) vitamin D was inversely associated with leptin even after adjustment for body mass index (BMI) (r = –0.340, p = 0.009). Conversely, 25(OH) vitamin D was not related with other parameters, such as BMI, blood pressure, lipids, glucose, insulin, homeostasis model assessment (HOMA) index, adiponectin, leptin/adiponectin ratio, and visfatin levels. Following supplementation in 15 vitamin D insufficient adolescents with obesity, 25(OH) vitamin D significantly increased (from 17.3 (12.5–27.8) to 32.6 (14.3–68.0) ng/ml, p = 0.005) and so did low-density lipoprotein cholesterol (LDL-C) (from 85.4 ±9.5 to 92.1 ±15.8 mg/dl, p = 0.022), while there were reductions in glycated haemoglobin (HbA_1c) (from 5.8 ±0.2 to 5.5 ±0.1%, p = 0.03) and leptin (from 19.7 (7.8–45.5) to 15.1 (4.3–37.3) ng/ml, p = 0.03). Oxidised LDL, paraoxonase, arylesterase, and urine isoprostanes remained unchanged.

Conclusions

Adolescents with obesity had lower 25(OH) vitamin D, which may be associated with higher leptin levels. Vitamin D supplementation may lead to HbA_1c and leptin reductions, but also to an increase in LDL-C.

Effects of Vitamin D Status on Inflammatory Markers in Obese Subjects: A Systematic Review

Background:

Recent studies have demonstrated the role of micronutrients in the manifestation of comorbidities associated with obesity. Vitamin D deficiency, in particular, appears to be associated with increased levels of inflammatory markers, which may lead to chronic low-grade inflammation, elevating the risk of chronic diseases such as diabetes, metabolic syndrome, and cardiovascular disease. The objective of this study was to perform a systematic review of observational studies conducted to investigate the effect of vitamin D deficiency on inflammatory markers in obese subjects.

Methodology:

This systematic review was conducted in accordance with the “STROBE” and PRISMA recommendations. Observational studies that evaluated the effect of vitamin D status on inflammatory markers in obese subjects were selected and reviewed. Searches were conducted in the PubMed, SciVerse Scopus, and Web of Science databases from February 21 to 22, 2018.

Results:

After the selection and removal of duplicate articles, 10 eligible articles were identified. Results from eight observational studies showed an association between vitamin D deficiency or insufficiency in the body and increased concentrations of inflammatory markers in obese individuals. On the other hand, two of the studies did not demonstrate any correlation. With regard to the inflammatory markers evaluated, eight studies showed high concentrations of ultra-sensitive C-reactive protein, five studies found an increase in interleukin-6 concentrations, and two studies noted increased levels of tumor necrosis factor.

Conclusion:

The data presented in this systematic review provide evidence of the association between vitamin D deficiency and increased inflammation in obesity.

Associations of C-reactive Protein with 25-hydroxyvitamin D in 24 Specific Diseases: A Cross-sectional Study from NHANES

Most diseases might be associated with acute or chronic inflammation, and the role of vitamin D in diseases has been extensively explored in recent years. Thus, we examined the associations of one of the best markers for inflammation ― C-reactive protein (CRP) with 25-hydroxyvitamin D [25(OH)D] in 24 specific diseases. We performed cross-sectional analyses among 9,809 subjects aged ≥18 years who participated in the U.S. National Health and Nutrition Examination Survey (NHANES) in 2007~2010. The generalized additive model (GAM) was used to explore the associations of CRP with 25(OH)D in different diseases, adjusted for the age, gender, examination period and race. Distributions of CRP were significantly different (P < 0.05) in gender, examination period and race, and distributions of 25(OH)D were different (P < 0.05) in the examination period and race. Generally, CRP was negatively associated with 25(OH)D for majority diseases. 25(OH)D was negatively associated with CRP generally, and the associations were disease-specific and disease category-specific. In respiratory, gastrointestinal and mental diseases, the associations tended to be approximately linear. While in metabolic diseases, the associations were nonlinear, and the slope of the nonlinear curve decreased with 25(OH)D, especially when 25(OH)D < 30 μg/L.

Diet quality and nutrient density in subjects with metabolic syndrome: Influence of socioeconomic status and lifestyle factors. A cross-sectional assessment in the PREDIMED-Plus study

BACKGROUND

Socioeconomic disparities and lifestyle factors are likely to determine the overall quality of the diet. In addition, overeating is compatible with inadequate micronutrient intake and it can lead to adverse health outcomes.

OBJECTIVE

To assess adequacy of dietary nutrient intake and to investigate the influence of socioeconomic and lifestyle factors on nutrient density in a large primary cardiovascular prevention trial conducted in healthy participants with metabolic syndrome (MetS) to assess the cardiovascular effects of an energy-restricted Mediterranean diet (PREDIMED-Plus).

METHODS

Baseline cross-sectional analysis of the PREDIMED-Plus trial with 6646 Spanish participants (aged 55-75 years in men and 60-75 years in women) with overweight/obesity and MetS. Energy and nutrient intake (for 10 nutrients) were calculated using a validated 143-item Food Frequency Questionnaire (FFQ) and nutrient density was estimated dividing the absolute nutrient intake by total energy intake. The prevalence of inadequate intake was estimated according to dietary reference intakes. Multivariable linear regression models were fitted to examine associations between socioeconomic status or lifestyle factors and nutrient density.

RESULTS

A considerable proportion of the screened participants showed a deficient intake of vitamins A, D, E, B9, calcium, magnesium and dietary fibre. Inadequate intake of four or more of the ten nutrients considered was present in 17% of participants. A higher nutrient density was directly and significantly associated with female sex, higher educational level and a better adherence to the Mediterranean diet. Lifestyle factors such as non-smoking and avoidance of sedentary lifestyles were also independently associated with better nutrient density.

CONCLUSIONS

Patients with MetS, despite being overweight, exhibited suboptimal nutrient intake, especially among men. Low nutrient density diet can be largely explained by differences in socioeconomic and lifestyle factors. These results highlight the importance of focussing on nutritional education in vulnerable populations, taking into account nutrient requirements.

Hypovitaminosis D and Cardiometabolic Risk Factors in Adolescents with Severe Obesity

BACKGROUND/OBJECTIVES

Obesity is associated with cardiometabolic risk factors and with Vitamin D deficiency. The aim of this study was to examine the relationship between 25(OH)D concentrations and cardiometabolic risk factors in adolescents with severe obesity.

SUBJECTS/METHODS

A cross-sectional clinical assessment (body mass index, fat mass index, fat-free mass index, waist-to-height ratio, and blood pressure) and metabolic study (triglycerides, total cholesterol, HDL-C, LDL-C, glucose, insulin, HOMA-IR, leptin, calcium, phosphorous, calcidiol, and PTH) were carried out in 236 adolescents diagnosed with severe obesity (BMI z-score > 3.0, 99th percentile), aged 10.2-15.8 years. The criteria of the US Endocrine Society were used for the definition of Vitamin D status.

RESULTS

Subjects with Vitamin D deficiency had significantly elevated values (p < 0.05) for BMI z-score, waist circumference, waist z-score, body fat percentage, fat mass index, systolic and diastolic blood pressure, total cholesterol, triglycerides, LDL-C, insulin, HOMA-IR, leptin, and PTH than subjects with normal Vitamin D status. There was a significant negative correlation (p < 0.05) of serum 25(OH)D levels with body fat percentage, FMI, systolic BP, total cholesterol, triglyceride, LDL-C, glucose, insulin, HOMA-IR, leptin, and PTH.

CONCLUSIONS

Low Vitamin D levels in adolescents with severe obesity were significantly associated with some cardiometabolic risk factors, including body mass index, waist circumference, fat mass index, high blood pressure, impaired lipid profile, and insulin resistance.

Vitamin D and Cardio-Metabolic Risk Factors in Overweight Adults: An Overview of the Evidence

BACKGROUND

Several studies have suggested a potential association between low vitamin D serum levels and several pathological conditions apart from the well-known bone disorders. Thus, vitamin D insufficiency has been linked to cardiometabolic risk factors including obesity, insulin resistance, hypertension, dyslipidemia, as well as type 2 diabetes and cardiovascular disease.

OBJECTIVE

This review intends to provide an overview of recent evidence from clinical studies on vitamin D [25- hydroxyvitamin D (25(OH)D)] and cardiometabolic risk factors in overweight adults. Furthermore, we also discussed potential mechanisms and limits of the retrieved results.

METHODS

The search process was based on the selection of publications (RCT) listed in PubMed and Cochrane Library databases.

RESULTS

Vitamin D status evidenced an inversely strong association with subcutaneous adipose tissue and visceral adiposity, but not significantly related to other bodyweight measures (i.e., body mass index). Studies have shown a potential inverse association of hypovitaminosis D with insulin resistance and cardiovascular risk factors.

CONCLUSION

The mechanisms by which vitamin D deficiency enhances adiposity, as well as putative association with metabolic syndrome features, remain still unclear. Further investigation would be required to conclude whether vitamin D has an independent role in preventing cardiometabolic disorders.

Vitamin D levels are associated with metabolic syndrome in adolescents and young adults: The BCAMS study

BACKGROUND AND AIMS

The relationship between vitamin D deficiency and metabolic syndrome (MS) remains controversial with relatively sparse data among youth. Therefore, we attempted to explicate the association of 25-hydroxyvitamin D [25(OH)D] levels with MS in Chinese adolescents and young adults.

METHODS

A cohort of 559 subjects at elevated risk of MS were recruited at 14-28 years of age as a follow-up to the Beijing Child and Adolescent Metabolic Syndrome Study. Subjects underwent clinical assessment including a 2h-oral glucose tolerance test. The concentrations of 25(OH)D, glucose, insulin and lipids were determined. MS was defined using the 2009 harmonized definition.

RESULTS

The prevalence of vitamin D deficiency (< 20 ng/ml) was 78.3%. After adjusting for age, gender and season, 25(OH)D concentrations were negatively correlated with neck circumference, percent body fat, LDL cholesterol, fasting and 2h-glucose levels (all P < 0.05). 25(OH)D levels were significantly lower in participants with obesity, high triglycerides, type 2 diabetes, or MS, compared to their respective counterparts (all P < 0.05). After adjusting for potential confounders (e.g., body mass index), participants in the lowest 25(OH)D tertile were 2.5 times more likely to exhibit MS than were those in the highest tertile (Odds Ratio: 2.48; 95% CI: 1.13-5.45, P < 0.05).

CONCLUSIONS

Vitamin D deficiency was very common in this young Chinese population at risk for MS. Given this association between low vitamin D levels and MS, the role of vitamin D supplementation in Chinese youths needs further examination, particular in those at risk for MS.

Body Mass Index, Vitamin D, and Type 2 Diabetes: A Systematic Review and Meta-Analysis

The deficiency of vitamin D is prevalent all over the world. Studies have shown that vitamin D may play an important role in the development of obesity. The current study was conducted to quantitatively evaluate the association between serum 25-(OH) vitamin D levels and the risk of obesity in both diabetic and non-diabetic subjects. A systematic review and meta-analysis of observational studies was carried out for that purpose. We searched the Medline, PubMed, and Embase databases throughout all of March 2018. A total of fifty five observational studies for both diabetic and non-diabetic subjects were finally included in the meta-analysis. The data were analyzed by comprehensive meta-analysis software version 3 and the random effects model was used to analyze the data. The meta-analysis showed an overall inverse relationship between serum vitamin D status and body mass index (BMI) in studies of both diabetic (r = −0.173, 95% = −0.241 to −0.103, p = 0.000) and non-diabetic (r = −0.152, 95% = −0.187 to −0.116, p = 0.000) subjects. The evidence of publication bias was not found in this meta-analysis. In conclusion, the deficiency of vitamin D is associated with an increased level of BMI in the studies of both diabetic and non-diabetic subjects. Reliable evidence from well-designed future randomized controlled trials is required to confirm the findings from observational studies and to find out the potential regulatory effects of vitamin D supplementation to lower BMI.

Higher dietary intake of vitamin D may influence total cholesterol and carbohydrate profile independent of body composition in men with Chronic Spinal Cord Injury

STUDY DESIGN

A case-control design.

OBJECTIVES

To determine the effects of dietary vitamin D intake on insulin sensitivity (Si), glucose effectiveness (Sg), and lipid profile in individuals with spinal cord injury (SCI).

METHODS

20 male, paraplegic (T3-L1) with chronic (> one year) motor complete SCI (AIS A or B) were recruited. Three-day dietary records were analyzed for dietary vitamin D (calciferol), and participants were assigned to one of two groups, a high vitamin D intake group and a low vitamin D intake group based on the mid-point of vitamin D frequency distribution. Individuals in both groups were matched based on age, weight, time since injury and level of injury. Sg, Si and lipid profiles were measured of the two groups.

RESULTS

The high vitamin D group had an average intake of 5.33 ± 4.14 mcg compared to low vitamin D group, 0.74 ± 0.24 mcg. None of the 20 participants met the recommended guidelines for daily vitamin D intake. The higher vitamin D group had a significantly lower (P = 0.035) total cholesterol (148.00 ± 14.12 mg/dl) than the lower vitamin D group (171.80 ± 36.22 mg/dl). Vitamin D adjusted to total dietary intake was positively correlated to improvement in Si and Sg (P<0.05).

CONCLUSION

The findings suggest that persons with SCI consume much less than the recommended guidelines for daily vitamin D intake. However, a higher dietary intake of vitamin D may influence total cholesterol and carbohydrate profile as demonstrated by a significant decrease in total cholesterol and improvement in glucose homeostasis independent of body composition changes after SCI.

Serum vitamin D in obese and overweight subjects according to estimated glomerular filtration rate

OBJECTIVE

Obesity and renal disease are both associated with low serum 25(OH)D. The aims of the present study were to (a) assess vitamin D status and compare serum vitamin D levels in overweight/obese versus normal-weight individuals according to eGFR and (b) assess the role of 25(OH)D in the development of secondary hyperparathyroidism (SHPT).

DESIGN

Serum 25(OH)D, 1,25(OH)₂D, parathyroid hormone (PTH), calcium, and phosphate were measured in 104 subjects with BMI > 25 kg/m². Participants were categorized according to eGFR (ml/min/1.73m²): G1 ≥ 60 (n = 53), G2 30-59 (n = 35), and G3 15-29 (n = 16). Fifty normal-weight individuals with comparable eGFR served as controls: G1-nw (n = 23), G2-nw (n = 18), and G3-nw (n = 9).

RESULTS

25(OH)D levels were lower in G1 compared to those in G1-nw (21.7 ± 6.5 vs 26.5 ± 7.0 ng/ml, p = 0.005), G2 versus G2-nw (19.0 ± 6.0 vs 25.0 ± 5.2 ng/ml, p = 0.001), and G3 vs G3-nw (15.8 ± 4.7 vs 20.3 ± 4.5 ng/ml, p = 0.030). 1,25(OH)₂D and PTH levels were similar in obese/overweight versus normal-weight individuals in each of the eGFR categories. Factors independently associated with low 25(OH)D levels were BMI > 25 kg/m², lower eGFR, and female gender. Mean 25(OH)D levels were < 30 ng/ml in both overweight and controls, in all eGFR groups. SHPT was universally observed when eGFR was < 30 ml/min/1.73m².

CONCLUSIONS

Lower serum 25(OH)D but similar 1,25(OH)₂D and PTH levels were observed in overweight/obese compared to normal-weight individuals. Even though vitamin D insufficiency was common across all eGFR categories, secondary hyperparathyroidism was more prevalent as eGFR declined.

Two threshold levels of vitamin D and the prevalence of comorbidities in outpatients of a tertiary hospital

This study evaluated the number of comorbidities between two normal values of 25OHD in outpatients during 1 year of 25OHD measurements. Five hundred twenty-nine outpatients were included, patients with 25OHD ≥ 20 and < 30 ng/mL had the higher number of comorbidities, suggesting that for this specific population, 25OHD ≥ 30 ng/mL would be more appropriate. INTRODUCTION : This study evaluated the comorbidities between two values of 25OHD in outpatients of a tertiary hospital.

METHODS

This is a cross-sectional study with measures of 25OHD in 1-year period, excluding 25OHD < 20 and > 50 ng/mL, clinical research participants, and liver disease and chronic renal failure patients. Patients were divided into two groups: group 1 (G1), 25OHD ≥ 20 and < 30 ng/mL; and group 2 (G2), 250HD ≥ 30 and ≤ 50 ng/mL. Medical records were reviewed for demographic, laboratory, and comorbidity data.

RESULTS

From 529 outpatients included, 319 were in G1 (53.3 ± 15.8 years, 85% women), mean 25OHD 24.8 ± 2.8 ng/mL; and 210 outpatients in G2 (56.7 ± 16.0 years, 83% women), mean 25OHD was 36.8 ± 4.8 ng/mL. G1 had the higher number of comorbidities, including altered glycemia, dyslipidemia, hypothyroidism, urinary tract diseases, arthropathy, secondary hyperparathyroidism, anemia, and neurological and psychiatric disorders. Osteoporosis and hypothyroidism were more prevalent in G2. After binary logistic regression, the variables age (OR 0.988, CI 0.97-1.00, p = 0.048), osteoporosis (OR 0.54, CI 0.36-0.80, p = 0.003), dyslipidemia (OR 1.61, CI 1.10-2.39, p = 0.015), arthropathy (OR 2.60, CI 1.40-5.10, p = 0.003), anemia (OR 15.41, CI 3.09-280.08, p = 0.008), and neurological and psychiatric diseases (OR 3.78, CI 1.98-7.88, p = 0.001) maintained significance.

CONCLUSION

Patients with serum 25OHD ≥ 20 and < 30 ng/mL had higher prevalence of comorbidities compared to ≥ 30 ng/mL.

Vitamin D, parathyroid hormone and metabolic syndrome - the PORMETS study

BACKGROUND

Vitamin D (VitD) and parathyroid hormone (PTH) play important roles in calcium metabolism and skeletal homeostasis. Estimates of the VitD status in several European countries show large variations between them. In addition, no national population-based estimate has been published. VitD and PTH may also play important roles in cardiovascular risk, which has been suggested to be associated with metabolic syndrome (MetS) and is very prevalent in Portugal. The goal of our study was to evaluate the prevalence of hypovitaminosis D and its determinants as well as PTH serum level determinants and associations of the 25-hydroxyvitamin D and PTH serum levels with MetS and its individual components in a sample of the Portuguese mainland population.

METHODS

PORMETS is a national cross-sectional study that includes a total sample of 4095 adults. A subsample, including 500 participants, was randomly selected for the present study. A structured questionnaire was administered to collect information on personal medical histories and socio-demographic and behavioral characteristics. Blood pressure and anthropometrics measurements were performed. Fasting venous samples were collected and PTH and 25-hydroxyvitamin D were measured. VitD adequacy was classified according to the Institute of Medicine, and MetS was classified according to the Joint Interim Statement recommendations. Multiple linear regression and unconditional logistic regression models were used to estimate the associations between the levels of PTH and 25-hydroxyvitamin D and with MetS and its individual components.

RESULTS

The prevalence of VitD deficiency was 37.7%, and MetS was present in 191 participants (38.4%). The serum PTH levels showed a positive association (OR: 1.014; 95%CI: 1.002, 1.026) with the waist circumference component of MetS. The serum 25-hydroxyvitamin D levels were negatively associated with MetS (OR: 0.957; 95%CI: 0.922, 0.993) as well as with its blood pressure (OR: 0.949; 95%CI: 0.912, 0.987) and triglycerides (OR: 0.930; 95%CI: 0.892, 0.969) components.

CONCLUSION

This study showed a high national prevalence of hypovitaminosis D. The PTH levels showed a significant positive association with the WC component of MetS, and the VitD levels were negatively associated with the BP and triglycerides components as well as with the MetS.

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.

A systematic review of vitamin D status in southern European countries

PURPOSE

Despite an acknowledged dearth of data on serum 25-hydroxyvitamin D (25(OH)D) concentrations from Southern European countries, inter-country comparison is hampered by inconsistent data reporting. The purpose of the current study was to conduct a systematic literature review of available data on serum 25(OH)D concentrations and estimate vitamin D status in Southern European and Eastern Mediterranean countries, both at a population level and within key population subgroups, stratified by age, sex, season and country.

METHODS

A systematic review of the literature was conducted to identify and retrieve scientific articles reporting data on serum 25(OH)D concentration and/or vitamin D status following standard procedures.

RESULTS

Data were extracted from 107 studies, stratified by sex and age group, representing 630,093 individuals. More than one-third of the studies reported mean 25(OH)D concentrations below 50 nmol/L and ~ 10% reported mean serum 25(OH)D concentrations below 25 nmol/L. Overall, females, neonates/ infants and adolescents had the higher prevalence of poor vitamin D status. As expected, there was considerable variability between studies. Specifically, mean 25(OH)D ranged from 6.0 (in Italian centenarians) to 158 nmol/L (in elderly Turkish men); the prevalence of serum 25(OH)D < 50 nmol/L ranged from 6.8 to 97.9% (in Italian neonates).

CONCLUSIONS

Contrary to expectations, there was a high prevalence of low vitamin D status in the Southern Europe and the Eastern Mediterranean regions, despite abundant sunshine. These data further emphasize the need for strategies, such as fortification of foods with vitamin D and/or vitamin D supplementation, which will be tailored to the needs of specific population groups with higher risk of insufficiency or deficiency, to efficiently tackle the pandemic of hypovitaminosis D in Europe.

Effect of vitamin D status on lipid profile in premenopausal women: a cross-sectional study

High lipid levels play important roles in the pathogenesis of atherosclerosis and some authors suggest vitamin D deficiency as a risk factor for atherosclerosis. The aim of this study was to evaluate the effect of vitamin D status on lipid profile in premenopausal women.

Patients and methods

A total of 315 nonsmoking premenopausal female volunteers without diabetes mellitus were included in the study. Patients were divided into four subgroups. The groups were as follows: patients with less than or equal to 12 ng/ml (group 1, n=126) vitamin D levels, between 20 and 12 ng/ml (group 2, n=48), between 30 and 20 ng/ml (group 3, n=21), and at least 30 ng/ml (group 4, n=120) vitamin D levels. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and non-HDL-C levels of the four groups were compared.

Results

HDL-C levels of group 4 were the highest (P=0.03), and TG and non-HDL-C levels of group 1 were the highest (P=0.04, 0.016, respectively) in all groups. There was no significant difference between serum parathormone, calcium, and phosphorus levels of the four groups (P=0.778, 0.121, 0.184, respectively). In unadjusted analysis, 25-hydroxy vitamin D levels were found to be correlated negatively with BMI (P=0.0005), LDL-C (P=0.01), and non-HDL-C (P=0.003) and correlated positively with HDL-C levels (P=0.006). After adjustments for age, sex, BMI, and log parathormone levels were made, no correlation was found between 25-hydroxy vitamin D and lipid (TC, LDL-C, HDL-C, and TG) levels (P=0.91, 0.06, 0.95, 0.79, respectively).

Conclusion

There may be an association between vitamin D insufficiency and dyslipidemia. However, this association may depend on obesity.

Association of serum 25-hydroxyvitamin D3 with adipokines and inflammatory marker in persons with prediabetes mellitus

BACKGROUND

The association of vitamin D status and inflammation prediabetes mellitus (PreDM) individuals has not been investigated. We investigated the association of serum 25-hydroxyvitamin D₃ (25(OH) D₃) with adipokines and inflammatory markers in persons with PreDM.

METHODS

In this cross-sectional study, we stratified 418 nondiabetic subjects as having PreDM or normal fasting glucose (NFG), and divided PreDM or NFG subjects into vitamin D sufficient, vitamin D insufficient and vitamin D deficient subgroups. 25(OH) D₃ concentrations were determined by HPLC. Serum tumor necrosis factor-α (TNF-α), interleiukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP), adiponectin, leptin and resistin were measured by ELISA.

RESULTS

In the PreDM group, compared with those in the vitamin D sufficient subgroup, vitamin D insufficient subgroup and vitamin D deficient subgroup had higher concentrations of hs-CRP and leptin (P<0.05). In the PreDM-deficient or PreDM-insufficient subgroup, mean hs-CRP and leptin concentration was higher than in the PreDM-sufficient, NFG-deficient, NFG-insufficient and NFG-sufficient subgroups (P<0.05). Serum 25(OH) D₃ concentrations were inversely associated with hs-CRP and leptin concentrations after adjusted the BMI only in the PreDM group (P<0.05). At the multivariate analysis, hs-CRP and leptin were the major determinant of 25(OH) D₃ concentration (β=-0.174 and β=-0.171, respectively).

CONCLUSIONS

25(OH) D₃ status in PreDM individuals was inversely correlated with concentrations of hs-CRP and leptin, suggesting their involvement in the inflammation response between vitamin D status and PreDM.

Active vitamin D treatment in CKD patients raises serum sclerostin and this effect is modified by circulating pentosidine levels

BACKGROUND AND AIMS

1,25(OH)₂Vitamin D increases the expression of the sclerostin gene. Whether vitamin D receptor activation (VDRA) influences serum sclerostin in CKD and whether compounds interfering with VDRA like Advanced Glycosylation End Products (AGEs) may alter the sclerostin response to VDRA is unknown.

METHODS AND RESULTS

Eighty-eight stage G3-4 CKD patients randomly received 2 μg paricalcitol (PCT)/day (n = 44) or placebo (n = 44) for 12 weeks. Sclerostin, a major AGE compound like pentosidine, and bone mineral disorder biomarkers were measured at baseline, at 12 weeks and 2 weeks after stopping the treatments. At baseline, in the whole study population sclerostin correlated with male gender (P = 0.002), BMI (P < 0.001), waist circumference (P < 0.001), serum pentosidine (P = 0.002) and to a weaker extent, with diabetes (P = 0.04), 1,25(OH)₂Vitamin D (r = 0.22, P = 0.04) and serum phosphate (r = -0.26, P = 0.01). Sclerostin increased during PCT treatment (average + 15.7 pg/ml, 95% CI: -3.0 to +34.3) but not during placebo (P = 0.03) and the PCT effect was abolished 2 weeks after stopping this drug. The increase in sclerostin levels induced by PCT was modified by prevailing pentosidine levels (P = 0.01) and was abolished by statistical adjustment for simultaneous changes in PTH but not by FGF23 changes.

CONCLUSIONS

VDRA by paricalcitol causes a moderate increase in serum sclerostin in CKD patients. Such an effect is abolished by adjustment for PTH, suggesting that it may serve to counter PTH suppression. The sclerostin rise by PCT is attenuated by pentosidine, an observation in keeping with in vitro studies showing that AGEs alter the functioning of the VDRA.

Relationship between Serum Vitamin D Status and Metabolic Risk Factors among Korean Adults with Prediabetes

Serum vitamin D status has been associated with prediabetes and metabolic syndrome. Evidence for the increased risk of metabolic disorders in individuals with prediabetes and a low vitamin D status is limited and uncertain. Furthermore, it has not been confirmed whether this possible relationship occurs in the Korean population. The aim of this study was to assess serum vitamin D status and to examine the relationship between serum vitamin D levels and metabolic risk factors in Korean adults with prediabetes. This cross-sectional study was conducted among 60 subjects aged 20-65 years. Participants had fasting glucose levels of 100 to 125 mg/dl. A questionnaire was used to assess vitamin D synthesis from sun exposure and a dietary intake examined using 3-days dietary records. Clinical and biochemical data were also collected. The 2009 harmonized definition of metabolic syndrome was used. Serum vitamin D levels were classified according to criteria from the 2011 Institute of Medicine report. The majority of subjects (75%) had a serum 25(OH)D level < 20 ng/ml, and among them, 31.1% were vitamin D deficiency (< 12 ng/ml). The proportion (42.9%) of subjects having low HDL-cholesterol was the highest among vitamin D deficiency (< 12 ng/ml) group (12 to < 20 ng/ml: 16.1%, ≥ 20 ng/ml: 6.7%). We observed an inverse relationship between 25(OH)D levels and TG, AI (β = -6.355, SE = 2.463; β = -0.020, SE = 0.008) after adjusted confounders. Korean adults with prediabetes were more likely to have low serum 25(OH)D levels. A sufficient 25(OH)D level may have possible beneficial effects on lipid profiles.

An Updated Mini Review of Vitamin D and Obesity: Adipogenesis and Inflammation State

Vitamin D related research continues to expand and theorise regarding its involvement in obesity, as both hypovitaminosis D and obesity strike in pandemic proportions. Vitamin D plays an important role in immune system through Vitamin D Receptors (VDR), which are transcription factors located abundantly in the body. Due to this characteristic, it is potentially linked to obesity, which is a state of inflammation involving the release of cytokines from adipose tissue, and exerting stress on other organs in a state of positive energy balance. Research trials in the past couple of years and systematic reviews from SCOPUS and MEDLINE will be discussed. The role of Vitamin D throughout the lifespan (from fetal imprinting until older age), and in various other obesity mediated chronic conditions shall be highlighted. Various mechanisms attributed to the inverse relationship of Vitamin D and obesity are discussed with research gaps identified, particularly the role of adipokines, epigenetics, calcium and type of adipose tissue.

Interplay of vitamin D and metabolic syndrome: A review

Vitamin D deficiency is a worldwide public health problem. Vitamin D deficiency plays key role in the pathophysiology of risk factors of metabolic syndrome which affect cardiovascular system, increase insulin resistance and obesity, stimulate rennin-angiotensin-aldosterone system that cause hypertension. The discovery of vitamin D receptor expressed ubiquitously in almost all body cells such as immune, vascular and myocardial cells, pancreatic beta cells, neurons and osteoblasts suggests an involvement of vitamin D mediated effects on metabolic syndrome. Moreover vitamin D deficiency as well as cardiovascular diseases and related risk factors frequently co-occur. This underlines the importance of understanding the role of vitamin D in the context of metabolic syndrome. The paper provides an insight into the physiology of vitamin D and relationship of vitamin D deficiency with risk factors of metabolic syndrome through observational and supplementation studies.

Parathyroid hormone, cardiovascular and all-cause mortality: A meta-analysis

BACKGROUND

Inconsistent findings have reported on parathyroid hormone (PTH) concentration and cardiovascular or all-cause mortality.

OBJECTIVE

To investigate whether elevated PTH concentration was an independent predictor for cardiovascular or all-cause mortality in the general population by conducting a meta-analysis based on prospective studies.

METHOD

We searched Cochrane Library, Pubmed, and Embase databases up to June 2015. Only prospective studies evaluating serum PTH concentration and cardiovascular or all-cause mortality were included. Pooled adjust risk ratio (RR) and corresponding 95% confidence intervals (CI) were calculated for the highest vs. lowest PTH concentration.

RESULTS

Ten studies with 31,616 subjects were identified and analyzed. Compared the highest to the lowest PTH concentration, elevated serum PTH concentration increased the risk of all-cause mortality (RR 1.19; 95% CI 1.08-1.30) but not for cardiovascular mortality (RR 1.26; 95% CI 0.96-1.66). Subgroup analyses indicated that cardiovascular mortality risk appeared to be more pronounced among men (RR 1.68; 95% CI 1.05-2.67).

CONCLUSIONS

Elevated PTH concentration is an independent predictor of all-cause mortality. Elevated serum PTH concentration appears to increase risk of cardiovascular mortality among men.

Relationship Between Parathormone and Obesity-Linked Disorders

BACKGROUND

In this study, we aimed to investigate whether high parathormone (PTH) levels in obese patients contribute to the metabolic complications of obesity.

METHODS

A total of 400 obese subjects aged 18-65 years were included. Anthropometric bioelectrical bioimpedance measures, blood tests, and 75 gram oral glucose tolerance test results were evaluated.

RESULTS

Of the 400 obese subjects, 335 were female. The mean age was 39 ± 10 years. The median body mass index was 36 (interquartile range 34-41). Subjects were divided into quartiles according to blood PTH levels. Groups included quartile 1 [n = 100, median PTH; 42 (range 36-45)], quartile 2 [n = 100, median PTH; 55 (51-59)], quartile 3 [n = 100, median PTH; 73 (68-78)], and quartile 4 [n = 100, median PTH; 99 (89-125)]. Quartiles were evaluated with a generalized linear model adjusted for age, sex, and season of recruitment. Systolic and diastolic blood pressure, fasting glucose, homeostatic model assessment-estimated insulin resistance, insulin sensitivity index, triglyceride level, and high-density lipoprotein cholesterol (HDL-C) were not different among quartiles. PTH and 25 hydroxyvitamin D (25(OH)D) were not associated with higher odds of prevalent metabolic syndrome in obese subjects (odds ratio, OR, 0.99 [95% confidence interval, CI, 0.981.00], P = 0.38 and 0.99 95% CI 0.96-1.01], P = 0.46, respectively). Decreased 25(OH)D levels were significantly correlated with higher odds of low HDL-C (OR 0.96 [95% CI 0.93-0.99], P = 0.04).

CONCLUSIONS

PTH does not contribute to the occurrence of metabolic components of obesity, but there is a positive correlation between 25(OH)D and HDL-C.

A meta-analysis of the relationship between vitamin D deficiency and obesity

Previous epidemiologic studies suggested that vitamin D deficiency may be a risk factor of obesity. However, the result is still controversial. This meta-analysis aims to provide a comprehensive summary on the association between vitamin D deficiency and obesity. We systematically searched Pubmed database, Chinese Wanfang Data Knowledge Service Platform, and Chinese National Knowledge Infrastructure (CNKI), for the literatures on the relationship between vitamin D deficiency and obesity published from 2010 to 2015. The effect sizes of overall odds ratio (OR) and 95% confidence interval (CI) were estimated using Stata 11.0. Heterogeneity was evaluated using random-effects model and forest plots. Fifteen studies were eligible for inclusion in the meta-analysis, which included 3867 subjects with obesity and 9342 health subjects. Meta-analysis results showed that the prevalence of vitamin D deficiency was difference between obesity group and control group, and the pooled OR (95% CI) was 3.43 (2.33-5.06). The prevalence of vitamin D deficiency was associated with obesity in Asians and European-American, OR (95% CI) were 3.70 (1.98-6.90) and 3.09 (1.89-5.04), respectively. No publication bias was found in our study. vitamin D deficiency may be associated with obesity, irrespective of areas.

Vitamin D status and its associations with components of metabolic syndrome in healthy children

AIM

High prevalence of vitamin D insufficiency/deficiency has been reported in populations of different countries. The aim of this cross-sectional study was to determine the prevalence and association of vitamin D status with components of metabolic syndrome.

METHODS

Lipid profile indices, anthropometric indices [body mass index and waist circumference (WC)], insulin resistance index (HOMA-IR), systolic blood pressure (SBP), diastolic blood pressure (DBP), C-reactive protein, intact parathyroid hormone (iPTH), and serum 25-hydroxyvitamin D [25(OH)D] concentration were evaluated in 297 healthy schoolchildren aged 7-11 years. Multivariate linear regression was used to determine independent predictors associated with low serum 25(OH)D concentrations.

RESULTS

The mean serum 25(OH)D concentration was 14.12±8.20 ng/mL (35.3±20.5 nmol/L); 96% of children had low serum 25(OH)D levels, 31.0% were deficient, and 65.0% had insufficient levels of 25(OH)D. Vitamin D deficiency was higher in girls (χ²=13.66; p=0.00); 25(OH)D level was negatively associated with WC, HOMA-IR, SBP, DBP, and iPTH. In the multivariate model, WC, DBP, and HOMA-IR were significant independent predictor of low 25(OH)D concentrations.

CONCLUSION

The prevalence of low vitamin D level in the studied healthy children was high and it is correlated with some components of metabolic syndrome. Outdoor activity for optimum sun exposure and additional studies are needed to evaluate the underlying metabolic syndrome components and hypovitaminosis D complications.

Lower bone turnover markers in metabolic syndrome and diabetes: the population-based Study of Health in Pomerania

BACKGROUND AND AIMS

Accumulating evidence demonstrates an important interaction between bone and energy metabolism. We aimed to study the associations of three bone turnover markers (BTM: osteocalcin, beta-crosslaps, procollagen type 1 N-terminal propeptide) as well as of 25-hydroxyvitamin D and parathyroid hormone with metabolic syndrome (MetS) or type 2 diabetes mellitus (T2DM) in a large population-based cohort.

METHODS AND RESULTS

This cross-sectional study comprised 2671 adult men and women participating in the first follow-up of the population-based Study of Health in Pomerania (SHIP-1). Multivariable logistic regression analyses were performed to assess sex-specific associations between the BTMs, 25-hydroxyvitamin D or parathyroid hormone and metabolic disease. All models were adjusted for age, body mass index, smoking status, physical activity, estimated glomerular filtration rate and month of blood sampling. The models for women were further adjusted for menopausal status. Higher BTM or 25-hydroxyvitamin D concentrations were associated with significantly lower odds for metabolic disease, while there was no association between parathyroid hormone and MetS or T2DM.

CONCLUSION

Our results contribute to the accumulating evidence of a cross-sectional association between high BTM or 25-hydroxyvitamin D concentrations and a lower prevalence of MetS or T2DM. Further research is necessary to evaluate the mechanisms underlying these results.

Obesity and vitamin D deficiency: a systematic review and meta-analysis

Over the past decade, there have been an increasing number of studies on the association between vitamin D deficiency and anthropometric state. However, we did not identify any meta-analyses of the relationship between obesity and vitamin D deficiency in different age groups. Thus, we evaluated the association between obesity and vitamin D deficiency. We searched for observational studies published up to April 2014 in PubMed/Medline, Web of Science and Scopus databases. We performed a meta-analysis in accordance with the random-effects model to obtain the summary measurement (prevalence ratio, PR). Among the 29,882 articles identified, 23 met the inclusion criteria. The prevalence of vitamin D deficiency was 35% higher in obese subjects compared to the eutrophic group (PR: 1.35; 95% CI: 1.21-1.50) and 24% higher than in the overweight group (PR: 1.24; 95% CI: 1.14-1.34). These results indicate that the prevalence of vitamin D deficiency was more elevated in obese subjects. The vitamin D deficiency was associated with obesity irrespective of age, latitude, cut-offs to define vitamin D deficiency and the Human Development Index of the study location.

Obesity with and without metabolic syndrome: do vitamin D and thyroid autoimmunity have a role?

AIMS

To investigate serum levels of thyroid stimulating hormone (TSH), anti-thyroid peroxidase antibody (TPO), and 25(OH)D in the presence or absence of metabolic syndrome in an obese population.

METHODS

Data from a prospectively generated "Obesity Polyclinic" database that includes socio-demographic characteristics, anthropometric, and laboratory measurements of obese subjects were retrospectively analyzed. Subjects with body-mass index (BMI) ≥30kg/m(2) were eligible. After detailed analysis and exclusion of unavailable cases, subjects diagnosed with and without metabolic syndrome were compared for TSH, anti-TPO, and 25(OH)D.

RESULTS

Of the study participants (n=548; men/women, 64/484), 277 were diagnosed with metabolic syndrome [Met-S (+)]. Met-S (+) patients had a higher mean BMI (36.4 vs. 32.3kg/m(2), p<.001) and percentage body fat (PBF) (39.2 vs. 35.3%, p<.001), but similar TSH (2.1 vs. 2.2mIU/mL, p=.759), anti-TPO (12 vs. 13IU/mL, p=.483), 25(OH)D (13.2 vs. 12.6ng/mL, p=.409), and calcium-phosphorus product (28.7 vs. 29.5mg/dL, p=0.275), compared to Met-S (-) subjects. When serum TSH, anti-TPO, and 25(OH)D levels were analyzed according to tertiles for comparisons of fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, BMI, and PBF, only 25(OH)D levels were negatively correlated with BMI and PBF.

CONCLUSIONS

Although decreased 25(OH)D levels were related to the degree of obesity in obese subjects, serum 25(OH)D levels per se did not seem to be associated with metabolic syndrome. The prevalence of thyroid autoimmunity and hypothyroidism were high in this obese sample; however, neither serum TSH nor anti-TPO levels correlated with metabolic syndrome. Our findings did not support the hypothesis that thyroid autoimmunity and/or vitamin D status have a role in the development of metabolic disturbances in the obese population.

Obesity and cancer: the role of vitamin D

Background

It is estimated that 20% of all cancer cases are caused by obesity. Vitamin D is thought to be one of the mechanisms underlying this association. This review aims to summarise the evidence for the mediating effect of vitamin D on the link between obesity and cancer.

Methods

Three literature searches using PubMed and Embase were conducted to assess whether vitamin D plays an important role in the pathway between obesity and cancer: (1) obesity and cancer; (2) obesity and vitamin D; and (3) vitamin D and cancer. A systematic review was performed for (1) and (3), whereas a meta-analysis including random effects analyses was performed for (2).

Results

(1) 32 meta-analyses on obesity and cancer were identified; the majority reported a positive association between obesity and risk of cancer. (2) Our meta-analysis included 12 original studies showing a pooled relative risk of 1.52 (95% CI: 1.33-1.73) for risk of vitamin D deficiency (<50 nmol/L) in obese people (body mass index >30 kg/m²). (3) 21 meta-analyses on circulating vitamin D levels and cancer risk were identified with different results for different types of cancer.

Conclusion

There is consistent evidence for a link between obesity and cancer as well as obesity and low vitamin D. However, it seems like the significance of the mediating role of vitamin D in the biological pathways linking obesity and cancer is low. There is a need for a study including all three components while dealing with bias related to dietary supplements and vitamin D receptor polymorphisms.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-712) contains supplementary material, which is available to authorized users.