Cardio-Metabolic Disease Risks and Their Associations with Circulating 25-Hydroxyvitamin D and Omega-3 Levels in South Asian and White Canadians

Effect of vitamin D status and vitamin D supplementation on immune function and prevention of acute respiratory tract infections in dark-skinned individuals: a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis examined the evidence for a potential relationship between vitamin D status and vitamin D supplementation on immune function biomarkers and prevention of acute respiratory tract infections (ARTI) in dark-skinned individuals.

DESIGN

Six databases were searched (inception to December 2021) for randomised controlled trials (RCT) and observational studies. A narrative synthesis and random-effects meta-analysis were used to synthesise the findings.

SETTING

Not applicable.

PARTICIPANTS

Ethnic groups other than white, with or without a white comparator.

RESULTS

After duplicates were removed, 2077 articles were identified for screening. A total of eighteen studies (n 36 707), including seven RCT and 11 observational studies, met the inclusion criteria, and three RCT (n 5778) provided sufficient data of high enough quality to be included in a meta-analysis. An inverse association between vitamin D status and at least one inflammatory biomarker in black adults was found in three studies, and vitamin D status was inversely associated with ARTI incidence in black and Indigenous groups in two studies. There was no significant effect of vitamin D supplementation on differences in ARTI incidence in ethnic minority groups (OR, 1·40; 95 % CI: 0·70, 2·79; P = 0·34), nor African American (OR, 1·77; 95 % CI: 0·51, 6·19; P = 0·37) or Asian/Pacific (OR, 1·08; 95 % CI: 0·77, 2·68; P = 0·66) subgroups.

CONCLUSIONS

There is a lack of conclusive evidence supporting an association between vitamin D status and immune function or ARTI incidence in dark-skinned individuals. Further RCT in diverse ethnic populations are urgently needed.

Leptin-VEGF crosstalk in excess body mass and related disorders: A systematic review

By 2030, it is expected that a billion people will have suffer from obesity. Adipose tissue synthesizes leptin, an adipokine that affects cardiovascular risk. Leptin intensifies the synthesis of vascular endothelial growth factor (VEGF). Our study reviews recent reports on leptin-VEGF crosstalk in obesity and related disorders. PubMed, Web of Science, Scopus, and Google Scholar were searched. One hundred and one articles involving human, animal, and in vitro research were included. In vitro studies show the crucial role of interaction between endothelial cells and adipocytes and hypoxia as a factor that intensifies leptin's effects on VEGF. Leptin-VEGF crosstalk promotes the progression of cancer. The animal research reveal that a high-fat diet enhances leptin and VEGF crosstalk. Genetic and epigenetic mechanisms and procreator-offspring programming may be involved in leptin-VEGF crosstalk. Some female-specific characteristics of leptin-VEGF relation in obesity were observed. The human studies have shown that increased leptin and VEGF synthesis and leptin-VEGF crosstalk are factors linking obesity with elevated cardiovascular risk. The studies of the last 10 years documented a range of significant aspects of leptin-VEGF crosstalk specific for obesity and related disorders, shedding new light on the link between obesity and increased cardiovascular risk.

Anti-atherosclerotic Effects of Myrtenal in High-Fat Diet-Induced Atherosclerosis in Rats

The major cause of death worldwide is atherosclerosis-related cardiovascular disease (ACD). Myrtenal was studied to determine control rats were given standard diets and a high-fat diet was given to AS model groups. Atherosclerosis-related cardiovascular disease (ACD) is globally attributed to being a predominant cause of mortality. While the beneficial effects of Myrtenal, the monoterpene from natural compounds, are increasingly being acknowledged, its anti-atherosclerotic activity has not been demonstrated clearly. The present study is proposed to determine the anti-atherosclerotic activity of Myrtenal in high-fat diet-induced atherosclerosis (AS) rat models. Control groups were maintained with standard diets, the AS model rats were provided a high-fat diet, two of the experimental groups fed with a high-fat diet were treated with Myrtenal (50 mg/kg and 100 mg/kg), and one experimental group on high-fat diet was treated with simvastatin (10 mg/kg) for 30 days. The levels of inflammatory cytokines were analyzed using kits. The lipoproteins and the lipid profile were estimated using an auto-analyzer. The atherogenic index and marker enzyme activities were also determined. Serum concentrations of 6-keto-prostaglandin F1α (6-keto-PGF1α), thromboxaneB2 (TXB2), endothelin (ET), and nitric oxide (NO) were measured. The AS model groups indicated altered lipid profile, lipoprotein content, atherogenic index, calcium levels, HMG-CoA reductase activity, collagen level, and mild mineralization indicating atherosclerosis, while the AS-induced Myrtenal-treated groups demonstrated anti-atherogenic activity. The Myrtenal-treated groups exhibited a decreased TC, TG, and LDLc levels; increased HDLc levels; and a decline in the inflammatory cytokines such as CRP, IL-1β, IL-8, and IL-18 when compared to the untreated AS rats. Furthermore, Myrtenal decreased ET, TXB2, and 6-keto-PGF1α levels indicating its anti-atherosclerotic activity. The study results thus indicate that Myrtenal modulates the lipid metabolic pathway to exert its anti-atherosclerotic activity.

Very high prevalence of 25-hydroxyvitamin D deficiency in 6433 UK South Asian adults: analysis of the UK Biobank Cohort

Little research has assessed serum 25-hydroxyvitamin D (25(OH)D) concentration and its predictors in Western-dwelling South Asians in a relatively large sample size. This observational, cross-sectional analysis assessed baseline prevalence of 25(OH)D deficiency in UK-dwelling South Asians (aged 40-69 years, 2006-2010) from the UK Biobank Cohort. Serum 25(OH)D measurements were undertaken using the DiaSorin Liaison XL assay. Of 6433 South Asians with a 25(OH)D measurement, using commonly used cut-off thresholds, 55 % (n 3538) had 25(OH)D < 25 nmol/l (severe deficiency) and 92 % (n 5918) had 25(OH)D < 50 nmol/l (insufficiency). Of the participants with a measurement, 20 % (n 1287) had 25(OH)D concentration <15 nmol/l (very severe deficiency). When 824 participants with undetectable (<10 nmol/l) 25(OH)D measurements were included (total n 7257), 29 % (n 2105) had 25(OH)D < 15 nmol/l, 60 % (n 4354) had 25(OH)D < 25 nmol/l and 93 % (n 6749) had 25(OH)D < 50 nmol/l. Logistic regression predictors of 25(OH)D < 25 nmol/l included the following characteristics: being male; Pakistani; higher BMI; 40-59 years old; never consuming oily fish; summer sun exposure <5 h/d, not using a vitamin D-containing supplement, measurement in winter or spring and vegetarianism. In terms of region, median 25(OH)D concentration was 19-20 nmol/l in Scotland, Northern England, the Midlands and Wales. Across Southern England and London, it was slightly higher at 24-25 nmol/l. Our analyses suggest the need for increased awareness of vitamin D deficiency in South Asians as well as urgent public health interventions to prevent and treat vitamin D deficiency in this group.

Cutoff point estimation for serum vitamin D concentrations to predict cardiometabolic risk in Brazilian children

BACKGROUND/OBJECTIVES

To evaluate serum 25(OH)D concentrations and determine a cutoff point for cardiometabolic risk in children.

SUBJECT/METHODS

This is a cross-sectional study with a representative sample of 378 8-9-year-old children from all urban schools in the city of Viçosa, MG, Brazil. Sociodemographic data and information on lifestyle, and food consumption were collected. Biochemical evaluation included glucose, triglycerides, leptin, calcidiol [25(OH)D], and parathormone. Body composition was assessed by dual energy X-ray absorptiometry. Cardiometabolic risk was considered when nontraditional risk markers were detected, including triglyceride × glycemia index (TyG index), hyperleptinemia, and hypertriglyceridemic waist phenotype (HWP). The receiver operating characteristic curve (ROC) was used to define the cutoff point for serum 25(OH)D to predict cardiometabolic risk.

RESULTS

25(OH)D showed better predictive capacity for grouping of cardiometabolic risk markers than for either single or paired markers. The area under the curve for grouping of risk markers was 0.636 (95% CI: 0.585, 0.685, P < 0.001). The cutoff point to predict cardiometabolic risk was defined as 32.0 ng/mL.

CONCLUSION

25(OH)D presented good predictive capacity for cardiometabolic risk and 25(OH)D concentration higher than 32 ng/mL was associated with a 49% reduction of cardiometabolic risk prevalence in prepubertal Brazilian children.

Low 25-hydroxyvitamin D levels are more prevalent in Canadians of South Asian than European ancestry inhabiting the National Capital Region of Canada

The US Institute of Medicine defined serum 25-hydroxyvitamin D (25OHD) cut point values of 30 nmol/L and 40 nmol/L were used to assess the vitamin D status of South Asian and European Canadians of self-identified ancestry living in the National Capital Region of Canada. Serum 25OHD values were measured in the spring and fall of 2012 to represent status during the winter and summer months, respectively. A total of 1238 measurements were obtained from 669 participants (49% South Asian ancestry): some participants were measured only once (spring or fall). Median 25OHD values were significantly higher in participants of European ancestry: 70.8 nmol/L (68.1, 73.5; 95% CI) versus South Asian ancestry: 42.7 nmol/L (40.5, 45.0; P<0.001). Spring vs. fall differences were small for each ethnic group and significant only for those of European ancestry (2.9, CI: 1.0–4.9 nmol/L; P = 0.01). Among participants of South Asian ancestry, 27.3% (fall) and 29.1% (spring) of females had values <40 nmol/L while the percentages for males were considerably higher (36.5% and 44.2%, respectively). The corresponding values for participants of European ancestry were ≤10%, showing that the South Asian participants were less likely to achieve the 25OHD concentrations established by the IOM for optimum bone health. Investigation of the factors related to serum 25OHD levels showed that supplement intake and ethnic background were associated with the biggest differences. Skin color was not a major factor, suggesting that genetic factors are responsible for the observed differences between participants of different ethnic backgrounds.

Dietary L-lysine supplementation altered the content of pancreatic polypeptide, enzymes involved in glutamine metabolism, and β-actin in rats

This study investigated the effects of Lys supplementation on serum pancreatic polypeptide (PP), glutamine (Gln) levels and the expression of PP, Gln synthetase (GlnS), glutaminase (Gls) and β-actin in different tissues such as pancreas, skeletal muscle, liver and kidney in rats. Male Sprague-Dawley rats were fed diets containing 7% casein supplemented with either 0% (Control), 1%, 1.5%, 3% Lys or 3% Lys with 1.5% Arg for a week. All rats were necropsied for collection of blood and tissues. Expression of PP, GlnS, Gls, and β-actin in tissues were determined using Western blotting. The results showed that the rats fed 3% supplemental Lys had significantly lower body weight gain (BWG) and food intake than the ≤ 1.5% Lys groups (P < 0.05). Supplementation with ≥ 1% Lys increased serum PP level (P < 0.05), but had no significant effect on pancreatic PP abundance (P > 0.05). GlnS expression was significantly lowered in skeletal muscle by ≥ 1.5% supplemental Lys compared to the Control (P < 0.05). The expression of Gls in the kidney was increased by the addition of 1.5% Arg to 3% Lys diet (P < 0.05). Liver β-actin significantly increased with both Lys and Arg supplementation and muscle β-actin significantly decreased (P < 0.05) with ≥ 1.5% supplemental Lys. Kidney β-actin significantly increased with Arg supplementation vs 3% Lys alone (P < 0.05). These results showed that dietary supplementation with ≥ 1.5% Lys significantly suppressed GlnS expression in the skeletal muscle, which may contribute to the decreased serum Gln levels, and that increased serum PP by Lys may be due to suppressed catabolism rather than increased synthesis of PP. Lys-induced PP may play a role in reducing food intake and BWG.

Vitamin D supplement use and associated demographic, dietary and lifestyle factors in 8024 South Asians aged 40-69 years: analysis of the UK Biobank cohort

OBJECTIVE

Vitamin D deficiency (serum 25-hydroxyvitamin D<25nmol/L) is extremely common in western-dwelling South Asians but evidence regarding vitamin D supplement usage in this group is very limited. This work identifies demographic, dietary and lifestyle predictors associated with vitamin D supplement use.

DESIGN

Cross-sectional analysis of baseline vitamin D supplement use data.

SETTING

UK Biobank cohort.

SUBJECTS

In total, n 8024 South Asians (Bangladeshi, Indian, Pakistani), aged 40-69 years.

RESULTS

Twenty-three % of men and 39% of women (P<0.001) [22% of Bangladeshis, 32% of Indians, 25% of Pakistanis (P<0.001)] took a vitamin D containing supplement. Median vitamin D intakes from diet were low at 1.0-3.0 micrograms per day, being highest in Bangladeshis and lowest in Indians (P<0.001). Logistic regression modelling showed that females had a higher odds of vitamin D supplement use than males (odds ratio (OR) = 2.02; 95% confidence interval (CI) 1.79 to 2.28). A lower supplement usage was seen in younger persons (40-60 years) (OR=0.75; 95% CI 0.65 to 0.86 reference= >60 years), and those living outside of Greater London (OR=0.53 to 0.77), with borderline trends for a lower body mass index, higher oily fish intake and higher household income associated with increased odds of vitamin D supplement use.

CONCLUSIONS

Vitamin D supplements were not used by most South Asians and intakes from diet alone are likely to be insufficient to maintain adequate vitamin D status. Public health strategies are now urgently required to promote the use of vitamin D supplements in these specific UK South Asian subgroups.

South Asians: why are they at a higher risk for cardiovascular disease?

PURPOSE OF REVIEW

We comment on the high prevalence of cardiovascular disease (CVD) in South Asians (SA). The effect of various risk factors, for example biochemical, genetic, lifestyle, socioeconomic factors and psychosocial stress on CVD risk is discussed.

RECENT FINDINGS

'Prediabetes' is common in SA, but its relationship with coronary artery disease (CAD) is not significant unlike for the white population. At the same time, 'prediabetes' in SA is associated with an increased risk for cerebrovascular disease (CeVD). The differentiating factor could be the high lipids in Europeans and their relationship to CAD. Likewise, higher diastolic blood pressure in SA may explain the risk of CeVD. Small, dense, low-density lipoprotein (LDL), low high-density lipoprotein-cholesterol (HDL-C) concentration and high triglycerides may contribute to atherosclerosis. Thrombotic factors such as increased levels of plasminogen activator inhibitor, fibrinogen, lipoprotein (a) and homocysteine have been shown to be associated with increased CVD. Impaired cerebrovascular autoregulation and sympathovagal activity, increased arterial stiffness and endothelial dysfunction may increase CVD risk further. In addition, environmental and dietary factors may exaggerate the unfavourable cardiovascular profile through genetic factors.

SUMMARY

The implications of the findings suggest comprehensive screening of SA for CVD. Cultural differences should be considered while designing prevention strategies specifically targeting barriers for uptake of preventive service.

Physical activity and nutrition intervention for Singaporean women aged 50 years and above: study protocol for a randomised controlled trial

BACKGROUND

The majority of the older Singaporean women aged 50 years and above are physically inactive and have unhealthy dietary habits, placing them at 'high risk' of non-communicable diseases (NCDs). The adoption of regular physical activity (PA) and a healthy diet are essential lifestyle behaviours to reduce this risk. This randomised controlled trial (RCT) involves the development, implementation and evaluation of a PA and nutrition programme for community-dwelling Singaporean women who currently attend recreational centres (RCs are public facilities supporting social leisure activities) in their local area. The intervention will be developed after conducting formative evaluation with RC attendees and managers through focus group discussions and pilot testing of resources (i.e. surveys, accelerometers, and health booklets). Programme ambassadors (trained, certified fitness instructors and nutritionists) will deliver all sessions in English and Mandarin; implement classes to meet participants' varying needs; and conduct sessions at different times at convenient venues. Social Cognitive Theory (SCT) has been selected as the theoretical framework to inform intervention strategies as it explores the interactions of human behaviour with the environment and has been found to be valuable when developing behavioural change interventions particularly in older adults (J Gerontol B Psychol Sci Soc Sci 67B(1):18-26, 2012; Obesity Reviews 15(12):983-95, 2014). Its major construct, self-efficacy, is invaluable in achieving successful behaviour change, such as increasing levels of PA or improving dietary intake (Trials. 2017; https://doi.org/10.1186/s13063-016-1771-9 ; Psychol Health Med 18(6):714-24, 2013).

METHODS

The development and implementation of the PA and nutrition intervention strategies will be guided by SCT and Motivational interviewing (MI) and implemented by trained programme ambassadors at the RCs. Sixty RCs located in Singapore will be selected from five major geographical districts and randomly allocated to the intervention (n = 30) or control (n = 30) cluster. A sample of 600 (intervention n = 300; control n = 300) women aged 50 years and above will then be recruited from these 60 centres and only the intervention group will be enrolled into the PA and nutrition intervention. It is hypothesised that by the end of the intervention, the intervention group participants compared to the control group will show significantly greater improvements in the following outcome variables: PA and dietary behaviours, health-related quality of life, objective measures of PA, anthropometric, lipid and glucose profiles. Data will be collected at baseline and 6 months and analysed using mixed regression models.

DISCUSSION

It is anticipated that recruitment, retention and compliance of participants will be challenging due to the target group being unfamiliar with such community-based research programmes.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry, ACTRN12617001022358. Registered on 14 July 2017.  https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372984&isReview=true.

Omega-3 Index and Anti-Arrhythmic Potential of Omega-3 PUFAs

Omega-3 polyunsaturated fatty acids (PUFAs), namely eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are permanent subjects of interest in relation to the protection of cardiovascular health and the prevention of the incidence of both ventricular and atrial arrhythmias. The purpose of this updated review is to focus on the novel cellular and molecular effects of omega-3 PUFAs, in the context of the mechanisms and factors involved in the development of cardiac arrhythmias; to provide results of the most recent studies on the omega-3 PUFA anti-arrhythmic efficacy and to discuss the lack of the benefit in relation to omega-3 PUFA status. The evidence is in the favor of omega-3 PUFA acute and long-term treatment, perhaps with mitochondria-targeted antioxidants. However, for a more objective evaluation of the anti-arrhythmic potential of omega-3 PUFAs in clinical trials, it is necessary to monitor the basal pre-interventional omega-3 status of individuals, i.e., red blood cell content, omega-3 index and free plasma levels. In the view of evidence-based medicine, it seems to be crucial to aim to establish new approaches in the prevention of cardiac arrhythmias and associated morbidity and mortality that comes with these conditions.