Vitamin D Status Is Associated with Metabolic Syndrome in a Clinic-Based Sample of Hispanic Adults

Vitamin D status and prevalence of metabolic syndrome by race and Hispanic origin in US adults: findings from the 2007-2014 NHANES

BACKGROUND

Vitamin D status has been found to be inversely associated with metabolic syndrome (MetS) in some studies. Vitamin D status varies by race and ethnicity, and the association of MetS with vitamin D status in US adults and by race and Hispanic origin has not been evaluated extensively.

OBJECTIVES

We aimed to examine the associations between vitamin D status and MetS overall, and across race and Hispanic origin groups, in a nationally representative sample of US adults who participated in the NHANES from 2007 to 2014.

METHODS

The total sample included 8639 adults, ≥20 y of age. Serum vitamin D was measured using a standardized LC-tandem MS method and was categorized using data-driven tertiles. MetS was defined using measured waist circumference, triglycerides, HDL cholesterol, blood pressure, and fasting glucose. Multivariable logistic regression models were fitted [accounting for sociodemographic and lifestyle factors, dietary supplement use, and BMI (in kg/m2)] to examine the associations of serum vitamin D with MetS among adults overall, and by race and Hispanic origin.

RESULTS

Serum vitamin D in the lowest tertile (≤56 nmol/L) was significantly associated with increased odds of MetS compared with the highest tertile (>77.9 nmol/L) (fully adjusted model OR: 1.85; 95% CI: 1.51, 2.27). Inverse associations were noted for all race-Hispanic origin groups: non-Hispanic white (NHW) (OR: 2.24; 95% CI: 1.67, 3.01), non-Hispanic black (OR: 1.56; 95% CI: 1.06, 2.29), and Hispanic (OR: 1.48; 95% CI: 1.03, 2.14) adults.

CONCLUSIONS

Lower vitamin D status was significantly associated with MetS among US adults after adjusting for sociodemographic and lifestyle factors, dietary supplement use, and BMI. This finding was noted across all race and Hispanic origin groups, although the strength of the association varied, being strongest for NHW adults.

Insulin Resistance Is Inversely Associated with the Status of Vitamin D in Both Diabetic and Non-Diabetic Populations

Vitamin D has been implicated in the regulation of glucose metabolism and insulin resistance. We designed this study to provide evidence that insulin resistance is dependent on the concentration of vitamin D in the body. Forty observational studies of both type 2 diabetes mellitus patients and healthy subjects were included in this meta-analysis. Related articles were searched from Embase, PubMed, and Medline through January 2021. Filters for search were used to obtain more focused results. We used Comprehensive Meta-Analysis Version 3 for the construction of forest plots. RevMan software version 5.3 was used to build the risk of bias tables and summary plots. The observational studies included in this systematic review and meta-analysis showed an inverse relationship of insulin resistance with the status of vitamin D both in non-diabetic (r = -0.188; 95% CI = -0.141 to -0.234; p = 0.000) and diabetic (r = -0.255; 95% CI = -0.392 to -0.107, p = 0.001) populations. From the meta-analysis we concluded that hypovitaminosis D is related to increased levels of insulin resistance in both type 2 diabetes patients and the healthy population all over the world.

Vitamin D Status and Correlation with Glucose and Lipid Metabolism in Gansu Province, China

OBJECTIVE

To investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and blood glucose and lipid levels in people over 18 years of age in Gansu, China.

SUBJECTS AND METHODS

A total of 1928 volunteers (958 males and 970 females) were selected. The prevalence of abnormal glucose metabolism and lipid metabolism in the vitamin D deficiency group (<20 ng/mL) and the non-vitamin D deficiency group (≥20 ng/mL) were compared. The correlations between serum 25(OH)D and blood glucose and lipid were analyzed.

RESULTS

A total of 1681 patients had 25(OH)D deficiency, with an overall prevalence of 87.2% (82.9% in males and 91.4% in females). The levels of 25(OH)D in the diabetic group and the IGT/IFG group were significantly lower than that in the normal group. The level of 25(OH)D was significantly lower in the dyslipidemia group than that in the normal group, and was significantly lower in the fasting plasma glucose (FPG) ≥5.6 mmol/L group than that in the FPG <5.6 mmol/L group (p=0.002). The 25(OH)D level in the serum triglyceride (TG) ≥1.7 mmol/L group was significantly lower than that of the TG <1.7 mmol/L group (p=0.0274). The age, heart rate, TG, TC, FPG and H₂PG levels in the vitamin D deficiency group were significantly higher than those in the non-vitamin D deficiency group (p<0.05). The prevalence of FPG ≥5.6 mmol/L in the vitamin D deficiency group was higher than that in the non-vitamin D deficiency group (23.5% vs 16.6%, p=0.016). Multiple linear regression analysis suggested that serum 25(OH)D levels were independently correlated with gender, age, FPG, TG and heart rate (β=-0.218, -0.129, -0.075, β=-0.103, -0.058, all p<0.05).

CONCLUSION

The incidences of dyslipidemia and dysglycemia were higher in the vitamin D deficiency group. The vitamin D level was independently and negatively correlated with FPG and TC, but not with waist circumference, BMI and blood pressure.

Predictors of 25-hydroxyvitamin D status among individuals with metabolic syndrome: a cross-sectional study

BACKGROUND

The risk of metabolic syndrome can be influenced by inadequate vitamin D levels, and exposure to sunlight is the main external source of vitamin D. The present study assessed the influence of environmental, biological, and nutritional factors in relation to seasonal 25-hydroxyvitamin D (25OHD) concentration in individuals with metabolic syndrome.

METHODS

This cross-sectional study enrolled 180 individuals with metabolic syndrome aged between 18 and 80 years. The 25OHD concentration was considered the dependent variable; independent variables included age, sex, skin color, use of sunscreen, skin type, sun exposure score, ultraviolet radiation index, geographic location, season, body mass index, waist:hip ratio, waist circumference, parathyroid hormone level, total serum calcium level, and calcium and vitamin D intake.

RESULTS

The average vitamin D in individuals evaluated in summer 32 ± 10 ng/mL was greater than in the winter 26 ± 8 ng/mL (p < 0.017). HDL-cholesterol was the only component of the MetS that differed significantly between the seasons (p < 0.001), showing higher concentrations in autumn 45 ± 8 mg/dL than in summer 35 ± 8 mg/dL. In the multiple regression model, gender, WHR, sun exposure score, and winter vs. summer explained 10% of the variation in 25OHD concentration (p = 0.004).

CONCLUSIONS

Sex, waist:hip ratio, sun exposure, and summer season were predictors of 25OHD status among individuals with metabolic syndrome. HDL-cholesterol was the only component of metabolic syndrome that differed significantly between the seasons.

Metabolic Syndrome and Vitamin D Levels in Patients with Obstructive Sleep Apnea Syndrome

BACKGROUND

Numerous studies have indicated that obstructive sleep apnea syndrome (OSAS), may contribute to the development of metabolic syndrome (MetS) and diabetes. Moreover, OSAS has been associated with lowered vitamin D (Vit D) levels, but reports are inconclusive. Aim of the study was to compare Vit D levels according to the presence of MetS and its components in OSAS patients.

METHODS

The presence of MetS was evaluated and serum 25-hydroxy vitamin D [25(OH)D] levels were measured in consecutive newly diagnosed, by polysomnography, subjects with OSAS.

RESULTS

A total of 107 subjects (88 men) with OSAS were included in the study. Patients were divided into group A (OSAS with MetS group: 55 subjects) and group B (OSAS without MetS: 52 subjects). There were no differences between the two groups in terms of age, body mass index, and sleep parameters. Patients in group A exhibited higher levels of daytime sleepiness, as expressed by Epworth Sleepiness Scale score (12 ± 5.5 vs. 9.3 ± 4.8 for groups A vs. B, p = 0.008). Serum 25(OH)D levels were significantly decreased in group A, as compared with group B (18 ± 8.6 ng/mL vs. 23.9 ± 14.1 ng/mL, respectively, p = 0.012). Group A was then subdivided in two smaller groups, according to patients' metabolic index: OSAS patients with metabolic score = 3 and OSAS patients with metabolic score >3. Serum 25(OH)D levels were higher in OSAS patients with metabolic score = 3 compared with OSAS patients with metabolic score >3 (19.8 ± 8.9 ng/mL vs. 15.1 ± 7.3 ng/mL respectively, p = 0.038).

CONCLUSIONS

OSAS patients with concurrent MetS exhibit lower serum Vit D levels, as compared with those without MetS.

Correlates and family aggregation of vitamin D concentrations in school-aged children and their parents in nine Mesoamerican countries

Objective

To determine the associations of sociodemographic characteristics, diet and outdoor activity as an indicator of sun exposure with serum 25-hydroxyvitamin D (25(OH)D) concentrations in children and their parents from Mesoamerica. We also quantified family aggregation of serum 25(OH)D.

Design

Cross-sectional study. Serum 25(OH)D concentrations were quantified using immunoassay. We compared the distribution of 25(OH)D concentrations in adults and children by levels of each correlate with the use of linear regression. Family aggregation was estimated using Pearson and intraclass correlation coefficients.

Setting

Capital cities of Guatemala, El Salvador, the Dominican Republic, Honduras, Nicaragua, Costa Rica, Panama and Belize, and Tuxtla Gutiérrez in Mexico.

Subjects

Children (n223) aged 7–12 years and 492 parents.

Results

Mean (sd) 25(OH)D concentrations in adults and children were 81·3 (21·1) and 79·5 (18·1) nmol/l, respectively. Prevalence of vitamin D deficiency (VDD; 25(OH)D <50 nmol/l) was 3·9 % among adults and 3·6 % among children. In adults, adjusted mean 25(OH)D concentrations were highest in Nicaragua (P<0·0001). Serum 25(OH)D was positively related to time spent gardening (P=0·03). Among children, 25(OH)D concentrations were positively associated with male sex (P=0·005), dairy intake (P=0·03) and mother’s serum 25(OH)D concentrations (P<0·0001); and inversely associated with mother’s BMI (P=0·02) and number of home assets (P=0·04). Family membership explained 31 % of the variability in 25(OH)D concentrations; aggregation was highest between mothers and children.

Conclusions

VDD prevalence was low in this study. Sociodemographic characteristics, diet and outdoor activity predict serum 25(OH)D. Family aggregation of serum 25(OH)D is high between mothers and children.