Vitamin D, endothelial function and cardio-metabolic health

PhD ThesisThe classical actions of vitamin D are to maintain bone health but vitamin D receptors are also expressed in several other tissues including the vascular system. The epidemiological evidence supports the associations between vitamin D status and vascular health but it is still uncertain whether the inadequate vitamin D status represents a risk factor for cardiovascular diseases (CVD). Nitric oxide (NO) is a soluble gas synthesized from the amino acid Larginine and plays an important role in maintaining vascular homeostasis. A reduced NO availability is an important hallmark of endothelial dysfunction, which is closely linked to the development of atherosclerosis and is an independent risk factor for cardiovascular events. Vitamin D may be involved in the maintenance of endothelial function (EF) through regulation of endothelium nitric oxide synthase (eNOS) activity which enhanced NO synthesis. This PhD project investigated the association between vitamin D intake and status, endothelial function and biomarkers of NO availability. In the first phase of the PhD, a systematic review and meta-analysis of randomized clinical trials was conducted to investigating the effects of vitamin D supplementation on EF. Overall, this showed no improvement of EF after vitamin D supplementation but there was evidence of positive effects in obese individuals and in diabetic patients. Next, a cross sectional study in postmenopausal overweight and obese women was conducted to evaluate the associations between vitamin D status and physiological and circulating biomarkers of EF. The study revealed increased pulse wave velocity (PWV), a marker of arterial stiffness, and higher concentrations of asymmetric dimethylarginine (ADMA, a marker of NO availability) in those women with vitamin D concentrations < 30 nmol/L. Detailed laboratory experiments were also conducted as part of this project to improve the measurement of concentrations of NO3 - and NO2 - in plasma and urine using ozone-based chemiluminescence. The final phase of the project investigated the association between whole-body NO availability (measured by a non-invasive stable-isotopic method), PWV, ADMA and vitamin D status and whether these associations were modified by age. The study did not find a significant association of NO production with vitamin D. However, NO production was significantly lower in older individuals and was significantly associated with systolic blood pressure and PWV.Malaysian government (Majlis Amanah Rakyat [MARA]

Prevalence of Metabolic Syndrome and Factors Associated with it among Women in Felda Palong, Gemas, Negeri Sembilan

A cross sectional study was carried out to assess the diet, physical activity and the prevalence of metabolic syndrome (MS) of 106 women aged 45 to 60 years old living in Felda Palong 4, 5 and 6, Gemas, Negeri Sembilan. The data collection processes included interviews, anthropometric measurements, blood pressure measurements and blood lipid sample collection. Out of the total sample, 67.0% were Malays, 29.2% were Indians and 3.8% were Chinese. The educational level of respondents (37.7%) was primary school level. Most of the respondents were housewives (70.8%), with a majority of the respondents (60.4%) earning between RM400 and RM699 per month. For the anthropometric measurements, almost half of the respondents (47.2%) were overweight (Body Mass Index (BMI) 2 25.0 - 29.9). Majority of the respondents (74.5%) had waisthip- ratio (WHR) of more or equal to 0.85 and 81.1% had waist circumferences (WC) equal to or greater than 80 cm. The prevalence of hypercholesterolemia (total cholesterol (TC) 2 6.2mrnol/L) among respondents was 31.1%. Raised Low Density Lipoprotein- Cholesterol (LDL-C) was found in 43.4% of the respondents while low levels of High Density Lipoprotein- Cholesterol (HDL-C) were evident in 14.2% of the respondents. The prevalence of high blood pressure and high blood glucose were 47.2% and 21.7% respectively. The dietary pattern of the respondents showed that their main sources of carbohydrate were rice and white bread. Their main sources of protein were chicken and fish while their sources of vitamins and minerals were fruits and vegetables. A high percentage of respondents were deficient in nutrients like potassium, vitamin C, fiber and calcium that were found to be lower than the Malaysian Recommended Nutrient Intake (RNI) and Daily Reference Value (DRV). On the other hand, the mean intakes of protein, carbohydrates, total fat, sodium, vitamin A, vitamin E and iron were found to be more than RNI and DRV. For physical activity, the mean kcal spent for physical activity was 1843+355. Most of the respondents (55.7%) were in the category of moderate PAL. By using International Diabetes Federation (IDF) criteria, the prevalence of metabolic syndrome significantly increased from 48.1% (NCEP ATPIII) to 54.7% (r = 0.724, ~ ~ 0 . 0 1R)e.s pondents with metabolic syndrome had significantly higher mean BMI, WC, WHR, systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), LDL-C and lower mean of HDL-C. BMI, WHR, SBP, DBP, FPG, triglycerides and HDL-C were found to be significantly associated with MS. The mean energy intake was 1846k450 kcal for subjects with MS and 1927f521 for subjects without MS, both lower than the Malaysian RNI (2180 kcal for female). Respondents with MS had higher protein, carbohydrate, total fat and sodium intakes whereas respondents without MS had higher energy intake, cholesterol, vitamin A, vitamin C, potassium, fiber, calcium and iron intakes. However, these differences were not statistically sigruficant except for vitamin C (p<0.05). The results s h d that intake of iron, d u r n and total fat were sigruficantly associated with metabolic syndrome while protein, vitamin A, vitamin C, ca-d fiber intake were not siwcant. In conclusion, this study found that there were associations between anthropometric measurements, blood pressure, fasting plasma glucose and lipid profiles also found that there were associations with metabolic syndrome. This study- between certain nutrient intakes and physical activity with metabolic syndrome. Therefore, there is a need to address these problems at national and regional level with the aim of early identification and prevention and appropriate community based intervention program should be reinforced to increase the awareness of the community on healthy living

The Effect of Caffeine Consumption on Sleep Quality among Undergraduate Students in Malaysia

This study aims to determine the effect of caffeine consumption on sleep quality among university students. This was a cross-sectional study that used a quantitative approach method. The data for this study was collected using a structured online questionnaire and distributed via online platforms to identify eligible participants. All the participants self-administered all three sections of the questionnaire, which were sociodemographic variables, the caffeine questionnaire tool, and the Pittsburgh Sleep Quality Index (PSQI). A chi-squared test was used to investigate the association between caffeine intake and sleep quality and the measured study characteristics. About 300 students, with a mean age of 21.95±1.43 years old, were recruited. The average caffeine intake of the study population was 193.54 mg per day. The respondents had good sleep quality was 44.7% while 55.3% had poor sleep. The study also found that there was a significant association between caffeine intake and sleep quality (p-value&lt;0.01). Meanwhile, there was no significant association between sociodemographic characteristics and caffeine intake or sleep quality. This study shows that a student's excessive intake of caffeine is correlated with poor sleep quality. Therefore, prevention strategies should be used to raise awareness of the issue and understand how consuming too much caffeine might result in poor sleep quality

Feasibility and acceptability of a dietary intervention study to reduce salt intake and increase high-nitrate vegetable consumption among middle-aged and older Malaysian adults with elevated blood pressure: a study protocol

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Introduction Global population ageing is one of the key factors linked to the projected rise of dementia incidence. Hence, there is a clear need to identify strategies to overcome this expected health burden and have a meaningful impact on populations’ health worldwide. Current evidence supports the role of modifiable dietary and lifestyle risk factors in reducing the risk of dementia. In South-East Asia, changes in eating and lifestyle patterns under the influence of westernised habits have resulted in significant increases in the prevalence of metabolic, cardiovascular and neurodegenerative non-communicable diseases (NCDs). Low vegetable consumption and high sodium intake have been identified as key contributors to the increased prevalence of NCDs in these countries. Therefore, nutritional and lifestyle strategies targeting these dietary risk factors are warranted. The overall objective of this randomised feasibility trial is to demonstrate the acceptability of a dietary intervention to increase the consumption of high-nitrate green leafy vegetables and reduce salt intake over 6 months among Malaysian adults with raised blood pressure. Methods and analysis Primary outcomes focus on feasibility measures of recruitment, retention, implementation and acceptability of the intervention. Secondary outcomes will include blood pressure, cognitive function, body composition and physical function (including muscle strength and gait speed). Adherence to the dietary intervention will be assessed through collection of biological samples, 24-hour recall and Food Frequency Questionnaire. A subgroup of participants will also complete postintervention focus groups to further explore the feasibility considerations of executing a larger trial, the ability of these individuals to make dietary changes and the barriers and facilitators associated with implementing these changes.http://dx.doi.org/10.1136/bmjopen-2019-03545310pubpub

Feasibility and Acceptability of a Dietary Intervention to Reduce Salt Intake and Increase High-Nitrate Vegetable Consumption in Malaysian Middle-Aged and Older Adults with Elevated Blood Pressure: Findings from the DePEC-Nutrition Trial

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420The DePEC-Nutrition trial is a complex dietary and behavioural intervention of salt intake reduction combined with increased high-nitrate vegetable consumption among Malaysian middle-aged and older adults with elevated blood pressure. This study aimed to assess the feasibility and acceptability of the trial. Participants were recruited from the South East Asia Community Observatory (SEACO) database and randomised into one of four groups: (1) low salt; (2) high-nitrate vegetable; (3) combined high-nitrate vegetable and low salt; and (4) control. The intervention included a combination of group counselling sessions, information booklets, reinforcement videos and text messages to modify dietary behaviour. The primary outcomes evaluated were the measures of feasibility and acceptability of (1) recruitment, follow-up attendance and retention; (2) data collection procedures and clinical outcome measures; and (3) individual and combined multi-modal dietary interventions. A total of 74 participants were recruited, and the 10-month retention rate was 73%. Data collection procedures were acceptable with minimal missing data. All intervention strategies were feasible and acceptable, with group counselling being the most acceptable strategy. This study provides important insights into improving the screening process of participants, facilitating their access to the research facilities and refining the measurement protocols and dietary recommendations, which are instrumental in formulating the design of a full-scale definitive DePEC-Nutrition trial.https://doi.org/10.3390/nu1403043014pubpub

Effects of vitamin D supplementation on endothelial function:a systematic review and meta-analysis of randomised clinical trials

Background: In addition to regulating calcium homoeostasis and bone health, vitamin D influences vascular and metabolic processes including endothelial function (EF) and insulin signalling. This systematic review and meta-analysis of randomised clinical trials (RCTs) were conducted to investigate the effect of vitamin D supplementation on EF and to examine whether the effect size was modified by health status, study duration, dose, route of vitamin D administration, vitamin D status (baseline and post-intervention), body mass index (BMI), age and type of vitamin D.  Methods: We searched the Medline, Embase, Cochrane Library and Scopus databases from inception until March 2015 for studies meeting the following criteria: (1) RCT with adult participants, (2) vitamin D administration alone, (3) studies that quantified EF using commonly applied methods including ultrasound, plethysmography, applanation tonometry and laser Doppler.  Results: Sixteen articles reporting data for 1177 participants were included. Study duration ranged from 4 to 52 weeks. The effect of vitamin D on EF was not significant (SMD: 0.08, 95 % CI −0.06, 0.22, p = 0.28). Subgroup analysis showed a significant improvement of EF in diabetic subjects (SMD: 0.31, 95 % CI 0.05, 0.57, p = 0.02). A non-significant trend was found for diastolic blood pressure (β = 0.02; p = 0.07) and BMI (β = 0.05; p = 0.06).  Conclusions: Vitamin D supplementation did not improve EF. The significant effect of vitamin D in diabetics and a tendency for an association with BMI may indicate a role of excess adiposity and insulin resistance in modulating the effects of vitamin D on vascular function. This remains to be tested in future studies

Recycling awareness and practices among Felda residents in southern region

Enabling sustainable development in Asia. The aims to provide a high‐impact platform bringing together researchers and multi‐stakeholders from academia, government and industry in Asia to share their expertise, knowledge and experiences in order to facilitate and catalyze the transformation of Low carbon society in Asia and beyond

Associations between Aging and Vitamin D Status with Whole-Body Nitric Oxide Production and Markers of Endothelial Function

BACKGROUND: Ageing and vitamin D deficiency have been associated with reduced nitric oxide (NO) synthesis and impaired endothelial function (EF) but the evidence in humans remains weak.OBJECTIVES: Two independent cross-sectional studies were designed to evaluate the association between age, sex and plasma vitamin D concentrations with physiological and biochemical biomarkers of NO synthesis and EF in young and older healthy participants (Study-1) and in overweight and obese post-menopausal women (Study-2).METHODS: In Study-1, forty young (20-49years) and older (50-75years) males and females (10 participants per age and sex group) were included. Resting blood pressure and ear-to-finger peripheral pulse wave velocity (PWV) were measured. A stable isotopic method was used to determine whole-body NO production. Plasma 25-hydroxyvitamin D (25(OH)D), nitrate, nitrite, and asymmetric dimethyl-arginine (ADMA) concentrations were determined. In Study-2, eighty older overweight and obese women (age 61.2±6.2years, BMI 29.5±4.4kg/m 2) were recruited. Post-occlusion reactive hyperaemia (PROH) and peripheral PWV were measured. Plasma concentrations of 25(OH)D, nitrate, cyclic guanosine monophosphate (cGMP), 3-nitrotyrosine (3-NT), endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and ADMA were determined. RESULTS: In Study-1, whole-body NO production was significantly greater in young compared with older participants (0.61±0.30μmol·hr -1·kg -1vs 0.39±0.10μmol·hr -1·kg -1, p=0.01) but there was no evidence of a sex difference (p=0.81). Plasma 25(OH)D concentration was not associated with PWV (r=0.18, p=0.28) or whole-body NO production (r=-0.20, p=0.22). Plasma ADMA concentration was associated positively with age (r=0.35, p=0.03) and negatively with whole-body NO production (r=-0.33, p=0.04). In Study-2, age was associated with lower PORH (r=-0.28, p=0.02) and greater ADMA concentrations (r=0.22, p=0.04). Plasma 25(OH)D concentration was inversely associated with 3-NT concentrations (r=-0.31, p=0.004). CONCLUSIONS: Older age was associated with lower whole-body NO production. Plasma vitamin D concentrations were not associated with NO production or markers of EF but showed a weak, significant correlation with oxidative stress in post-menopausal overweight women.</p

Feasibility and acceptability of a dietary intervention study to reduce salt intake and increase high-nitrate vegetable consumption among middle-aged and older Malaysian adults with elevated blood pressure:a study protocol

Daniel Reidpath - ORCID: 0000-0002-8796-0420 https://orcid.org/0000-0002-8796-0420Introduction Global population ageing is one of the key factors linked to the projected rise of dementia incidence. Hence, there is a clear need to identify strategies to overcome this expected health burden and have a meaningful impact on populations’ health worldwide. Current evidence supports the role of modifiable dietary and lifestyle risk factors in reducing the risk of dementia. In South-East Asia, changes in eating and lifestyle patterns under the influence of westernised habits have resulted in significant increases in the prevalence of metabolic, cardiovascular and neurodegenerative non-communicable diseases (NCDs). Low vegetable consumption and high sodium intake have been identified as key contributors to the increased prevalence of NCDs in these countries. Therefore, nutritional and lifestyle strategies targeting these dietary risk factors are warranted. The overall objective of this randomised feasibility trial is to demonstrate the acceptability of a dietary intervention to increase the consumption of high-nitrate green leafy vegetables and reduce salt intake over 6 months among Malaysian adults with raised blood pressure. Methods and analysis Primary outcomes focus on feasibility measures of recruitment, retention, implementation and acceptability of the intervention. Secondary outcomes will include blood pressure, cognitive function, body composition and physical function (including muscle strength and gait speed). Adherence to the dietary intervention will be assessed through collection of biological samples, 24-hour recall and Food Frequency Questionnaire. A subgroup of participants will also complete postintervention focus groups to further explore the feasibility considerations of executing a larger trial, the ability of these individuals to make dietary changes and the barriers and facilitators associated with implementing these changes.http://dx.doi.org/10.1136/bmjopen-2019-03545310pubpub

Feasibility and Acceptability of a Dietary Intervention to Reduce Salt Intake and Increase High-Nitrate Vegetable Consumption in Malaysian Middle-Aged and Older Adults with Elevated Blood Pressure: Findings from the DePEC-Nutrition Trial

The DePEC-Nutrition trial is a complex dietary and behavioural intervention of salt intake reduction combined with increased high-nitrate vegetable consumption among Malaysian middle-aged and older adults with elevated blood pressure. This study aimed to assess the feasibility and acceptability of the trial. Participants were recruited from the South East Asia Community Observatory (SEACO) database and randomised into one of four groups: (1) low salt; (2) high-nitrate vegetable; (3) combined high-nitrate vegetable and low salt; and (4) control. The intervention included a combination of group counselling sessions, information booklets, reinforcement videos and text messages to modify dietary behaviour. The primary outcomes evaluated were the measures of feasibility and acceptability of (1) recruitment, follow-up attendance and retention; (2) data collection procedures and clinical outcome measures; and (3) individual and combined multi-modal dietary interventions. A total of 74 participants were recruited, and the 10-month retention rate was 73%. Data collection procedures were acceptable with minimal missing data. All intervention strategies were feasible and acceptable, with group counselling being the most acceptable strategy. This study provides important insights into improving the screening process of participants, facilitating their access to the research facilities and refining the measurement protocols and dietary recommendations, which are instrumental in formulating the design of a full-scale definitive DePEC-Nutrition trial