Serum 25(OH)D and adipokines levels in people with abdominal obesity

Vitamin D and obesity

An inverse association between vitamin D status and obesity has been reported across diverse populations and age groups in humans. In animal model of diet-induced obesity, dysregulation of vitamin D metabolism has been observed. However, the causal relationship between vitamin D status and obesity is not conclusive. Several explanations, such as volumetric dilution, sequestration of vitamin D into adipose tissue, and limited sunlight exposure, have been suggested as the underlying mechanisms linking poor vitamin D status and obesity. Vitamin D can modulate adipose tissue biology, spanning from adipocyte differentiation to adipocyte apoptosis and energy metabolism, indicating its potential impact on adiposity. In this chapter, we will review the prevalence of vitamin D deficiency and determinants of vitamin D deficiency among different populations, as well as changes in vitamin D metabolism associated with obesity. Additionally, we will review vitamin D's regulation of adipogenesis and lipogenesis at the cellular level in order to gain a deeper understanding of the underlying mechanisms linking vitamin D levels and obesity.

Association of 25-hydroxyvitamin D levels with lipid profiles in osteoporosis patients: a retrospective cross-sectional study

BACKGROUND

In the literature, scarce data investigate the link between 25-hydroxyvitamin D (25[OH]D) and blood lipids in the osteoporosis (OP) population. 25(OH)D, as a calcium-regulating hormone, can inhibit the rise of parathyroid hormone, increase bone mineralization to prevent bone loss, enhance muscle strength, improve balance, and prevent falls in the elderly. This retrospective cross-sectional study aimed to investigate the association between serum 25(OH)D levels and lipid profiles in patients with osteoporosis, with the objective of providing insight for appropriate vitamin D supplementation in clinical settings to potentially reduce the incidence of cardiovascular disease, which is known to be a major health concern for individuals with osteoporosis.

METHODS

This is a retrospective cross-sectional study from the Affiliated Kunshan Hospital of Jiangsu University, including 2063 OP patients who received biochemical blood analysis of lipids during hospitalization from January 2015 to March 2022. The associations between serum lipids and 25(OH)D levels were examined by multiple linear regression. The dependent variables in the analysis were the concentrations of serum lipoprotein, total cholesterol (TC), triglycerides (TGs), apolipoprotein-A, lipoprotein A, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (LDL-C). The independent variable was the concentration of blood serum 25(OH)D. At the same time, age, body mass index, sex, time and year of serum analysis, primary diagnosis, hypertension, diabetes, statins usage, beta-C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide were covariates. Blood samples were collected in the early morning after the overnight fasting and were analyzed using an automated electrochemiluminescence immunoassay on the LABOSPECT 008AS platform (Hitachi Hi-Tech Co., Ltd., Tokyo, Japan). The generalized additive model was further applied for nonlinear associations. The inception result for smoothing the curve was evaluated by two-piecewise linear regression exemplary.

RESULTS

Our results proved that in the OP patients, the serum 25(OH)D levels were inversely connected with blood TGs concentration, whereas they were positively associated with the HDL, apolipoprotein-A, and lipoprotein A levels. In the meantime, this research also found a nonlinear relationship and threshold effect between serum 25(OH)D and TC, LDL-C. Furthermore, there were positive correlations between the blood serum 25(OH)D levels and the levels of TC and LDL-C when 25(OH)D concentrations ranged from 0 to 10.04 ng/mL. However, this relationship was not present when 25(OH)D levels were higher than 10.04 ng/mL.

CONCLUSIONS

Our results demonstrated an independent relationship between blood lipids and vitamin D levels in osteoporosis patients. While we cannot establish a causal relationship between the two, our findings suggest that vitamin D may have beneficial effects on both bone health and blood lipid levels, providing a reference for improved protection against cardiovascular disease in this population. Further research, particularly interventional studies, is needed to confirm these associations and investigate their underlying mechanisms.

Isolated vitamin D supplementation improves the adipokine profile of postmenopausal women: a randomized clinical trial

OBJECTIVE

The aim of the study is to evaluate the effect of vitamin D supplementation alone on the adipokine profile of postmenopausal women.

METHODS

In this randomized clinical trial, 160 women were randomized to 2 groups: oral supplementation with 1,000 IU cholecalciferol/d (vitamin D, n = 80) or placebo (PL, n = 80). Women with amenorrhea 12 months or more and aged 50 to 65 years were included. Women with established cardiovascular disease, insulin-dependent diabetes, renal failure, liver diseases, and previous use of menopausal hormone therapy and vitamin D were excluded. The intervention lasted 9 months and serum adiponectin, resistin, and adipsin levels were determined at the start and end of treatment. Intention to treat was adopted as the statistical method using a repeated measures design, followed by Wald's multiple comparison test adjusted for group × time interaction.

RESULTS

After 9 months, 25-hydroxyvitamin D concentrations increased from 15.0 ± 7.5 to 27.5 ± 10.4 ng/mL (+45.4%) in the vitamin D group and decreased from 16.9 ± 6. to 13.8 ± 6.0 ng/mL (-18.5%) in the PL group ( P < 0.001). In the vitamin D group, there was an increase in adiponectin (+18.6%) and a decrease in resistin (-32.4%, P < 0.05). At the end point, a difference was observed between the PL and vitamin D groups in mean adiponectin and resistin levels (11.5 ± 5.5 vs 18.5 ± 21.8 ng/mL, P = 0.047, and 16.5 ± 3.5 vs 11.7 ± 3.3 ng/mL, P = 0.027, respectively). There were no significant intervention effects on serum adipsin levels.

CONCLUSIONS

Daily supplementation with 1,000 IU of vitamin D alone was associated with an increase in adiponectin and a decrease in resistin, suggesting a beneficial effect on the adipokine profile of postmenopausal women with vitamin D deficiency.

Effects of Vitamin D Supplementation on Omentin-1 and Spexin Levels, Inflammatory Parameters, Lipid Profile, and Anthropometric Indices in Obese and Overweight Adults with Vitamin D Deficiency under Low-Calorie Diet: A Randomized Placebo Controlled Trial

Background and Aims

Improved vitamin D levels can have a favorable effect on some metabolic variables. The objective of the current study was to determine the effects of vitamin D supplementation during a weight-loss intervention on the levels of omentin-1, spexin, lipid profiles, and inflammatory factors in obese and overweight participants.

Methods and Materials

In this double-blind placebo-controlled randomized clinical trial, 70 overweight and obese participants with vitamin D deficiency (25(OH)D ≤ 20 nmol/L) were assigned into the intervention (a daily dose of 2,000 IU vitamin D + low-calorie diet) and placebo (placebo + low-calorie diet) groups for 8 weeks. Anthropometric parameters, serum levels of 25-hydroxy vitamin D (25(OH)D), lipid profiles, omentin-1 and spexin levels, high-sensitivity C-reactive protein (hs-CRP), and soluble intercellular adhesion molecule-1 (sICAM-1) concentrations were assessed before and after the intervention.

Results

Vitamin D supplementation after the intervention led to a significant decrease in triglycerides (TG) (P = 0.02), very-low-density lipoprotein-cholesterol (VLDL-C) (P = 0.02), and hs-CRP (P = 0.03) concentrations and a significant increase in the serum vitamin D level (P < 0.001). Furthermore, after adjusting for baseline values, age, and baseline BMI, the levels of serum high-density lipoprotein-cholesterol (HDL-C) (P = 0.01) increased significantly, and a significant reduction was observed in the concentration of sICAM-1 (P = 0.01) in the intervention group. However, we did not find any significant difference in serum omentin-1 and spexin concentrations between the groups after intervention.

Conclusions

Vitamin D supplementation along with a low-calorie diet (LCD) program for 8 weeks significantly decreased the inflammatory markers in obese individuals, while it did not alter serum omentin-1 and spexin concentrations.

How to apply the personalized medicine in obesity-associated asthma?

INTRODUCTION

Obesity-associated asthma (OA) is frequently severe, with an increased rate of hospitalizations, numerous comorbidities and low response to corticosteroids. Despite progress in applying for personalized medicine in asthma, no specific recommendations exist for the management of OA.

AREAS COVERED

The aim of this review is to summarize recent data about the relationship obesity-asthma, describe clinical characteristics, potential mechanisms involved and possible therapeutic interventions to improve OA outcomes. Extensive research in the PubMed was performed using the following terms: "asthma and obesity" and "obese asthma" in combination with "phenotypes", "airway inflammation", "biomarkers", "lung function", "weight loss", "lifestyle interventions", "therapies" Currently two phenotypes are described. Early-onset atopic asthma is conventional allergic asthma aggravated by the pro-inflammatory properties of adipose tissue in excess, while late-onset non-atopic asthma is due to airway dysfunction as a consequence of the chronic lung compression caused by the obese chest walls. Previous data showed that different therapeutic strategies used in weight loss have a positive impact on OA outcomes.

EXPERT OPINION

The presence of a multidisciplinary team (chest physician, nutritionist, exercise physiologist, physiotherapist, psychologist, bariatric surgeon) and the collaboration between different specialists are mandatory to optimize the management and to apply the personalized medicine in OA.

Associations of Serum 25-Hydroxyvitamin D with Adiposity and At-Risk Lipid Profile Differ for Indigenous (Orang Asli) Male and Female Adults of Peninsular Malaysia

BACKGROUND

Low vitamin D status, adiposity, and at-risk lipid profile are associated with adverse health consequences. This study aimed to assess serum 25(OH)D concentration of Indigenous (Orang Asli) adults and to determine the associations between serum 25(OH)D with adiposity and lipid profile, respectively.

METHODS

This cross-sectional study was conducted among 555 (164 men, 391 women) Orang Asli adults aged 18-65 years of Jah Hut sub-tribe in Krau Wildlife Reserve (KWR), Peninsular Malaysia. Demographic and socio-economic information were obtained using interviewer-administered questionnaire. Participants were also assessed for serum 25-hydroxyvitamin D (25(OH)D) concentration, adiposity indices (BMI, WC, WHtR, WHR, %BF) and lipid parameters (TC, LDL-C, HDL-C, TG). Data were analyzed using binary logistic regression via SPSS.

RESULTS

The prevalence of suboptimal 25(OH)D concentration was 26.3%, comprising 24.9% insufficiency (50 to <75 nmol/L) and 1.4% deficiency (<50 nmol/L). While men (14-30.5%) were associated with a more proatherogenic lipid profile than women (6.1-14.3%), more women were with central obesity (M: 19.5-46.3%; F: 34.5-49.1%) and suboptimal (<75 nmol/L) vitamin D status (M: 11.6%; F: 32.4%). While suboptimal 25(OH)D concentration was significantly associated with higher odds of at-risk LDL-C (p < 0.01) and obesity (WC, WHtR) (p < 0.05) in men, no significant association was observed for women. Nonetheless, it should be noted that there were only 19 men with suboptimal (<75 nmol/L) vitamin D status.

CONCLUSIONS

While suboptimal vitamin D status was relatively low in Orang Asli adults, the prevalence of obesity and undesirable serum lipids were relatively high. The sex-specific associations between vitamin D status with adiposity indices and serum lipids warrant further investigation.

Association between standardized vitamin 25(OH)D and dyslipidemia: a community-based study in Riyadh, Saudi Arabia

BACKGROUND

Vitamin D deficiency associated with dyslipidemia can contribute towards cardiovascular diseases. Previous studies have found that Saudi Arabia has a high burden of vitamin D deficiency and cardiovascular disease risk factors. We aimed to explore the relationship between vitamin D deficiency and dyslipidemia, including total cholesterol, low-density lipids, high-density lipids (HDL), and triglycerides (TG) in apparently healthy Saudi male and female participants aged 30-75 years.

METHODS

A cross-sectional study was conducted on 1717 apparently healthy Saudi participants from 18 primary health care centers in Riyadh. Data collectors conducted the interviews, took anthropometric measurements, and collected the blood samples. Serum 25-hydroxyvitamin vitamin D (25(OH)D) levels were measured using an electrochemiluminescence assay method. Lipid panel was measured by a fully automated analyzer using enzymatic methods.

RESULTS

Multivariable logistic regression analysis revealed that the adjusted odds ratio (ORA) of low level of HDL cholesterol in association with 25(OH)D deficiency was 2.1 times higher in males (ORA = 2.1; 95% CI = 1.1, 3.9) and 1.3 times higher in females (ORA = 1.3; 95% CI = 0.9, 1.9). A significant excess odds ratio of high levels of TG in association with 25(OH) D deficiency was observed in females (ORA = 3.0; 95% CI = 1.1, 7.9) but not in males.

CONCLUSION

Vitamin D deficiency is highly prevalent in Saudi Arabia. Low levels of HDL cholesterol in men and high TG levels in women are associated with vitamin D deficiency. The results emphasize the importance of treating vitamin D deficiency in the general population.

Obesity and severe asthma

Obesity is an important global health issue for both children and adults. Obesity increases the prevalence and incidence of asthma and also increases the risk for severe asthma. Here we describe the features of severe asthma phenotypes for which obesity is a defining characteristic, including steroid resistance, airway inflammation, and co-morbidities. We also review current concepts regarding the mechanistic basis for the impact of obesity in severe asthma, including possible roles for vitamin D deficiency, systemic inflammation, and the microbiome. Finally, we describe data indicating a role for diet, weight loss, and exercise in the treatment of severe asthma with obesity. Better understanding of the mechanistic basis for the role of obesity in severe asthma could lead to new therapeutic options for this population.

Longitudinal association of 25-hydroxyvitamin D with adipokines and markers of glucose metabolism among Brazilian pregnant women

This study aimed to evaluate the longitudinal association of vitamin D status with glycaemia, insulin, homoeostatic model assessment of insulin resistance, adiponectin and leptin. A prospective cohort with 181 healthy, pregnant Brazilian women was followed at the 5th–13th, 20th–26th and 30th–36th gestational weeks. In this cohort, 25-hydroxyvitamin D (25(OH)D) plasma concentrations were analysed using liquid chromatography–tandem MS. Vitamin D status was categorised as sufficient or insufficient using the Endocrine Society Practice Guidelines (≥75/<75 nmol/l) and the Institute of Medicine (≥50/<50 nmol/l) thresholds. Linear mixed-effect regression models were employed to evaluate the association between vitamin D status and each outcome, considering interaction terms between vitamin D status and gestational age (P<0·1). At baseline, 70·7 % of pregnant women had 25(OH)D levels <75 nmol/l and 16 % had levels <50 nmol/l. Women with sufficient vitamin D status at baseline, using both thresholds, presented lower glycaemia than those with insufficient 25(OH)D. Pregnant women with 25(OH)D concentrations <75 nmol/l showed lower insulin (β=−0·12; 95 % CI −0·251, 0·009;P=0·069) and adiponectin (β=−0·070; 95 % CI −0·150, 0·010;P=0·085) concentrations throughout pregnancy than those with 25(OH)D levels ≥75 nmol/l. Pregnant women with 25(OH)D <50 nmol/l at baseline presented significantly higher leptin concentrations than those with 25(OH)D levels ≥50 nmol/l (β=−0·253; 95 % CI −0·044, 0·550;P=0·095). The baseline status of vitamin D influences the biomarkers involved in glucose metabolism. Vitamin D-sufficient women at baseline had higher increases in insulin and adiponectin changes throughout gestation than those who were insufficient.

Hypocaloric Diet Prevents the Decrease in FGF21 Elicited by High Phosphorus Intake

The effect of dietary phosphorus (P) on fibroblast growth factor 21 (FGF21)/β-klotho axis was investigated in rats that were fed diets with: Normal (NP) or high P (HP) and either normal (NC), high (HC) or low calories (LC). Sampling was performed at 1, 4 and 7 months. Plasma FGF21 concentrations were higher (p < 0.05) in NC and HC than in LC groups. Increasing P intake had differing effects on plasma FGF21 in rats fed NC and HC vs. rats fed LC at the three sampling times. When compared with the NP groups, FGF21 concentrations decreased at the three sampling points in rats fed NC-HP (80 vs. 194, 185 vs. 382, 145 vs. 403 pg/mL) and HC-HP (90 vs. 190, 173 vs. 353, 94 vs. 434 pg/mL). However, FGF21 did not decrease in rats fed LC-HP (34 vs. 20, 332 vs. 164 and 155 vs. 81 pg/mL). In addition, LC groups had a much lower liver FGF21 messenger ribonucleic acid/glyceraldehyde 3-phosphate dehydrogenase (mRNA/GAPDH) ratio (0.51 ± 0.08 and 0.56 ± 0.07) than the NC-NP (0.97 ± 0.14) and HC-NP (0.97 ± 0.22) groups. Increasing P intake reduced liver FGF21 mRNA/GAPDH in rats fed NC and HC to 0.42 ± 0.05 and 0.37 ± 0.04. Liver β-klotho mRNA/GAPDH ratio was lower (p < 0.05) in LC groups (0.66 ± 0.06 and 0.59 ± 0.10) than in NC (1.09 ± 0.17 and 1.03 ± 0.14) and HC (1.19 ± 0.12 and 1.34 ± 0.19) groups. A reduction (p < 0.05) in β-klotho protein/α-tubulin ratio was also observed in LC groups (0.65 ± 0.05 and 0.49 ± 0.08) when compared with NC (1.12 ± 0.11 and 0.91 ± 0.11) and HC (0.93 ± 0.17 and 0.87 ± 0.09) groups. In conclusion β-klotho is potently regulated by caloric restriction but not by increasing P intake while FGF21 is regulated by both caloric restriction and increased P intake. Moreover, increased P intake has a differential effect on FGF21 in calorie repleted and calorie depleted rats.

Involvement of RBP4 in Diabetic Atherosclerosis and the Role of Vitamin D Intervention

The purposes of this study were to evaluate the expression of retinol-binding protein 4 (RBP4) in diabetic rats with atherosclerosis and to investigate the role of vitamin D intervention. Male Wistar rats were randomly divided into 4 groups, including the control group (NC), the diabetic rats (DM1), the untreated diabetic atherosclerosis rats (DM2), and the vitamin D-treated diabetic atherosclerosis rats (DM3). The levels of serum and adipose RBP4, fasting insulin (FINS), fasting plasma glucose (FPG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), 25-hydroxyvitamin D [25(OH)D], C-reactive protein (CRP), and systolic blood pressure (SBP) were measured. Homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment β-cell function index (HOMA-β), and atherogenic indexes (AI) were calculated. Compared with group NC, the levels of RBP4, TG, LDL-c, FPG, FINS, CRP, AI1, AI2, SBP, and HOMA-IR increased, while the levels of HDL-c, 25(OH)D, and HOMA-β decreased in groups DM1 and DM2. After 8 weeks of vitamin D supplementation in group DM3, the levels of 25(OH)D and HOMA-β increased and the levels of LDL-c, TC, HOMA-IR, FINS, CRP, RBP4, AI1, AI2, and SBP decreased significantly when compared with group DM2 (P < 0.05); Pearson analysis showed that serum RBP4 was positively correlated with TG, FINS, HOMA-IR, SBP, CRP, and AI and negatively correlated with 25(OH)D. In addition, multivariable logistic regression analysis showed that serum RBP4, SBP, and HDL-c were predictors for the presence of diabetic atherosclerosis. These findings suggested that RBP4 could involve in the improvement of diabetic atherosclerosis; vitamin D had the ability to decrease the level of RBP4 and eventually played an important role in preventing atherosclerosis in diabetes.

Vitamin D Supplementation Improves Quality of Life and Physical Performance in Osteoarthritis Patients

(1) Background: Lower levels of serum 25-hydroxyvitamin D (25(OH)D) are common in osteoarthritis (OA) patients. However, the effect of vitamin D supplementation on muscle strength and physical performance remains unclear. This study will investigate the effects of vitamin D₂ supplementation on muscle strength and physical performance in knee OA patients; (2) Methods: One hundred and seventy-five primary knee OA patients with low levels of serum 25(OH)D (<30 ng/mL) received 40,000 IU vitamin D₂ (ergocalciferol) per week for six months. Body composition, muscle strength, physical performance, serum 25(OH)D level, leptin, interlukin-6 (IL-6), parathyroid hormone (PTH), protein carbonyl, and metabolic profile were analyzed; (3) Results: Baseline mean serum 25(OH)D levels in knee OA patients was 20.73 ng/mL. Regarding baseline vitamin D status, 58.90% of patients had vitamin D insufficiency, and 41.10% had vitamin D deficiency. After vitamin D₂ supplementation for six months, mean serum 25(OH)D level was 32.14 ng/mL. For post-supplementation vitamin D status, 57.10% of patients had vitamin D sufficiency and 42.90% had vitamin D insufficiency. From baseline to six months, there was a significant increase in mean serum 25(OH)D level (p < 0.001), while mean LDL cholesterol (p = 0.001), protein carbonyl (p = 0.04), and PTH (p = 0.005) all significantly decreased. Patient quality of life (SF-12) and pain (visual analog scale, VAS) both improved significantly from baseline to the six-month time point (p = 0.005 and p = 0.002, respectively). Knee OA patients demonstrated significant improvement grip strength and physical performance measurements after vitamin D₂ supplementation (p < 0.05); (4) Conclusions: Vitamin D₂ supplementation for six months reduced oxidative protein damage, decreased pain (VAS), improved quality of life, and improved grip strength and physical performance in osteoarthritis patients.