Vitamin D concentrations in familial combined hyperlipidemia: effects of lipid lowering treatment

Familial combined hyperlipidemia: An overview of the underlying molecular mechanisms and therapeutic strategies

Among different types of dyslipidemia, familial combined hyperlipidemia (FCHL) is the most common genetic disorder, which is characterized by at least two different forms of lipid abnormalities: hypercholesterolemia and hypertriglyceridemia. FCHL is an important cause of cardiovascular diseases. FCHL is a heterogeneous condition linked with some metabolic defects that are closely associated with FCHL. These metabolic features include dysfunctional adipose tissue, delayed clearance of triglyceride-rich lipoproteins, overproduction of very low-density lipoprotein and hepatic lipids, and defect in the clearance of low-density lipoprotein particles. There are also some genes associated with FCHL such as those affecting the metabolism and clearance of plasma lipoprotein particles. Due to the high prevalence of FCHL especially in cardiovascular patients, targeted treatment is ideal but this necessitates identification of the genetic background of patients. This review describes the metabolic pathways and associated genes that are implicated in FCHL pathogenesis. We also review existing and novel treatment options for FCHL. © 2019 IUBMB Life, 71(9):1221-1229, 2019.

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.

Comparison of 25-hydroxyvitamin D and metabolic parameters between women with and without polycystic ovarian syndrome

Background There is increasing evidence that supports the contribution of vitamin D deficiency in metabolic disturbances among women with polycystic ovarian syndrome (PCOS). The aim of this study was to compare 25-hydroxyvitamin D level and the prevalence of metabolic syndrome in the PCOS and normal women. Materials and methods A case-controlled study was conducted in a teaching hospital over a 6-month duration from June 2015 to January 2016. A total of 90 women, who consisted of 45 women with PCOS (study group) and 45 women without PCOS (control group), were recruited. Results The final analysis was of 80 women only and the prevalence of vitamin D deficiency (<20 ng/mL) was high between both groups, i.e. 93.7% but there was no significant difference (p = 0.874). Nevertheless, the prevalence of metabolic syndrome was significantly higher in the study group as compared to the control group (27.5% vs. 5.0%, p = 0.013). There was no statistically significant correlation between vitamin D level with clinical [age, weight, body mass index (BMI), waist and hip circumference, systolic and diastolic blood pressure (SBP and DPB, respectively)] and metabolic parameters (fasting glucose, triglycerides, cholesterol, high-density lipoprotein and low-density lipoprotein) among women with PCOS. However, height was positively correlated (r = 0.338, p = 0.033) and the contrary waist-hip ratio was negatively correlated with vitamin D level (r = -0.605, p = 0.048). Conclusion The prevalence of vitamin D deficiency was high in our study population. Nevertheless, the prevalence of metabolic syndrome was higher among women with PCOS as compared to women without PCOS.

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.

Effect of vitamin D supplementation on cardiometabolic risks and health-related quality of life among urban premenopausal women in a tropical country--a randomized controlled trial

Background

Many observational studies linked vitamin D to cardiometabolic risks besides its pivotal role in musculoskeletal diseases, but evidence from trials is lacking and inconsistent.

Aim

To determine whether Vitamin D supplementation in urban premenopausal women with vitamin D deficiency can improve cardiometabolic risks and health-related quality of life (HRQOL).

Design

A double-blind randomized controlled trial was conducted in Kuala Lumpur, Malaysia. A total of 192 vitamin D deficient (<50 nmol/l) premenopausal women were randomized to receive either vitamin D 50,000 IU or placebo once a week for 2 months and then monthly for 10 months. Primary outcomes were serum 25(OH)D, serum lipid profiles, blood pressure and HOMA-IR measured at baseline, 6 months and 12 months. HRQOL was assessed with SF-36 at baseline and 12 months.

Results

Ninety three and ninety-nine women were randomised into intervention and placebo groups respectively. After 12 months, there were significant differences in the serum 25(OH)D concentration (mean difference: 49.54; 95% CI: 43.94 to 55.14) nmol/l) and PTH levels (mean difference: −1.02; 95% CI: −1.67 to −0.38 pmol/l) in the intervention group compared to placebo group. There was significant difference between treatment group in both serum 25(OH)D and PTH. There was no effect of supplementation on HOMA-IR, serum lipid profiles and blood pressure (all p>0.05) between two groups. There was a small but significant improvement in HRQOL in the components of vitality (mean difference: 5.041; 95% CI: 0.709 to 9.374) and mental component score (mean difference: 2.951; 95% CI: 0.573 to 5.329) in the intervention group compared to placebo group.

Conclusion

Large and less frequent dosage vitamin D supplementation was safe and effective in the achievement of vitamin D sufficiency. However, there was no improvement in measured cardiometabolic risk factors in premenopausal women. Conversely vitamin D supplementation improves some components of HRQOL.

Trial Registration

Australian New Zealand Clinical Trial Registry ACTRN12612000452897