Dietary intake of antioxidant vitamins and risk of stroke: the Japan Public Health Center-based Prospective Study

Fruit and Vegetable Intake and Risk of Disabling Dementia: Japan Public Health Center Disabling Dementia Study

BACKGROUND

Fruits and vegetables contain abundant amounts of antioxidant vitamins such as vitamin C, α-carotene, and β-carotene. Few prospective observational studies have investigated the effects of fruit and vegetable intake on the risk of dementia, and the results are inconsistent.

OBJECTIVES

Our aim was to examine associations between fruit and vegetable intake and the risk of disabling dementia.

METHODS

We conducted a follow-up survey within the Japan Public Health Center-based Prospective Study involving 42,643 individuals aged 50-79 y at baseline (2000-2003). Dietary fruit and vegetable intakes and related antioxidant vitamin intakes (i.e., α-carotene, β-carotene, and vitamin C) were determined using a food frequency questionnaire. The diagnosis of disabling dementia was made based on the daily living disability status related to dementia under the Japanese long-term care insurance program from 2006 to 2016. Hazard ratios and 95% confidence intervals for disabling dementia were estimated using area-stratified Cox proportional hazard models adjusted for potential confounding factors.

RESULTS

A total of 4994 cases of disabling dementia were recorded. We observed an inverse association between total fruit and vegetable intake and the risk of dementia among males and females: the multivariate hazard ratios (95% confidence intervals) for the highest compared with lowest quartiles of intake were 0.87 (0.76, 0.99) (P- trend = 0.05) among males and 0.85 (0.76, 0.94) (P- trend = 0.006) among females. Among antioxidant vitamins, vitamin C intake was inversely associated with the risk of dementia among males and females: the multivariate hazard ratios (95% confidence intervals) for the highest compared with lowest quartiles of intake were 0.71 (0.61, 0.84) (P- trend < 0.0001) among males, and 0.76 (0.67, 0.86) (P- trend < 0.0001) among females.

CONCLUSIONS

Fruit and vegetable intake and dietary intake of vitamin C may contribute to reducing the risk of disabling dementia among males and females.

Association between the Composite Dietary Antioxidant Index and Stroke: A cross-sectional Study

The composite dietary antioxidant index (CDAI) is indeed a valuable nutritional tool used to evaluate the overall antioxidant capacity of an individual's daily food consumption. The CDAI was calculated from the intake of six antioxidant components in the diet, including vitamin A, vitamin C and vitamin E, carotenoids, selenium, and zinc. This study aimed to determine the association between CDAI and stroke. Utilizing data from the 2003-2018 NHANES dataset, CDAI was computed by summarizing the intake of six dietary antioxidants based on 24-hour dietary recall interviews. The relationship between CDAI and stroke was examined using multivariate logistic regression and restricted cubic spline analysis. This study ultimately included 39,432 participants, of whom 1,527 (3.87%) had a stroke. The multivariate logistic regression model 3 that fully adjusted all confounding variables showed a negative association between CDAI and stroke (OR = 0.97; 95% CI:0.95, 0.99). The highest tertile of CDAI saw a 23% drop in the prevalence of stroke compared to the lowest tertile (OR = 0.77; 95%CI: 0.64,0.92). Restricted cubic spline suggested that this negative correlation was nonlinear with an inflection point of -2.99. Subgroup analyses and interaction tests showed that this negative correlation was more applicable in patients with prediabetes (P < 0.05). There was a non-linear negative correlation between CDAI level and stroke prevalence, and this correlation was more significant in people with pre-diabetes. Appropriate CDAI levels may contribute to the management of stroke risk.

The Role of Micronutrients in Neurological Disorders

Trace elements and vitamins, collectively known as micronutrients, are essential for basic metabolic reactions in the human body. Their deficiency or, on the contrary, an increased amount can lead to serious disorders. Research in recent years has shown that long-term abnormal levels of micronutrients may be involved in the etiopathogenesis of some neurological diseases. Acute and chronic alterations in micronutrient levels may cause other serious complications in neurological diseases. Our aim was to summarize the knowledge about micronutrients in relation to selected neurological diseases and comment on their importance and the possibilities of therapeutic intervention in clinical practice.

Prospective cohort study on potato intake and mortality from cardiovascular diseases: the Japan Collaborative Cohort Study (JACC study)

PURPOSE

The association between potato intake and risk of cardiovascular diseases is unknown. This study aimed to examine the association between potatoes intake and mortality from stroke and coronary heart disease among Japanese.

METHODS

The study included 74,750 participants of the Japan Collaborative Cohort Study, aged 40-79, who were initially free of cardiovascular diseases or cancer at baseline (1988-1990) and provided information on their potato intake. Hazard ratios and 95% confidence intervals were estimated by fitting a Cox proportional hazards model according to the frequency of potatoes intake (0, 0.4, 1.5, 3.5 and 7 servings per week) adjusting for geographic location, age, body mass index, drinking status, smoking status, perceived mental stress, education level, walking time, dietary intakes of total energy, meat, fish, vegetables, fruit, dairy products, cakes, and salt.

RESULTS

Over a median of 19.2 years of follow-up, 4908 deaths from cardiovascular diseases were identified: 1019 from coronary heart diseases and 2153 from strokes (738 ischemic strokes and 495 hemorrhagic strokes). After adjustment for potential confounding factors, the hazard ratio of mortality from cardiovascular diseases for daily potato intake compared with no potato intake was 0.82 (95% confidence interval: 0.70, 0.95) among women, and 1.01 (0.88, 1.16) among men. Among women, the multivariable hazard ratios were 0.67 (0.48, 0.96) for coronary heart disease, 0.83 (0.66-1.05) for total stroke, 0.70 (0.43-1.15) for hemorrhagic stroke, and 0.75 (0.49-1.13) for ischemic stroke.

CONCLUSION

We found an inverse association of potato intake with mortality from total cardiovascular diseases, especially that from coronary heart disease, among Japanese women. To our knowledge, this is the first report to show an inverse association between potato intake and total cardiovascular diseases.

Association between Dietary Total Antioxidant Capacity of Antioxidant Vitamins and the Risk of Stroke among US Adults

The intake of antioxidant vitamins can scavenge free radicals and reduce oxidative stress, which may be beneficial for stroke. However, the relationship between total antioxidant capacity (TAC) of antioxidant vitamins and stroke is controversial. This study aims to investigate the association between dietary TAC and the risk of stroke in US adults. This study included participants over 20 years old from the 2001-2018 National Health and Nutrition Examination Survey (NHANES). Data from two 24 h dietary recalls were used to estimate the usual intake of antioxidant vitamins. TAC was calculated by the vitamin C equivalent antioxidant capacity reference values of individual antioxidant vitamins. Survey-weighted generalized linear models were performed to evaluate the relationship between TAC and the risk of stroke. A restricted cubic spline regression model was used to investigate the dose-response association. A total of 37,045 participants was involved, of whom 1391 suffered a stroke. Compared with the first tertile, the participants in the second tertile of TAC showed a lower risk of stroke (OR = 0.788, 95% CI: 0.662, 0.936) after adjusting for potential risk factors. The dose-response analysis showed a gradual increase in the risk of stroke as TAC decreases. Subgroups analyses indicated that this association was primarily in the population of those aged over 60 years old, who were female, consumed alcohol, were a former smoker and inactive. The sensitivity analysis presented consistent results. These results suggest that deficiency of dietary TAC was associated with an increased risk of stroke, particularly in populations with underlying oxidative stress injury.

Vitamin C Intake and Ischemic Stroke

Vitamin C is an essential micronutrient with important antioxidant properties. Ischemic stroke is a major public health problem worldwide. Extensive evidence demonstrates that vitamin C has protective effects against cardiovascular disease, and there is a close relationship between vitamin C intake and ischemic stroke risk. Based on the evidence, we conducted this umbrella review to clarify the relationship between vitamin C intake and ischemic stroke risk from four perspectives: cellular mechanisms, animal experiments, clinical trials, and cohort studies.

Plasma Vitamin E and the Risk of First Stroke in Hypertensive Patients: A Nested Case-Control Study

Background: The association between plasma vitamin E levels and first stroke risk in men and women remains unclear. Objective: We aimed to examine the prospective association between plasma vitamin E and first stroke, and evaluate the effect modifiers for the association, among hypertensive patients. Design: The study sample was drawn from the China Stroke Primary Prevention Trial (CSPPT), which randomized a total of 20,702 hypertensive patients to a double-blind, daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. This nested case-control study, including 618 first stroke cases and 618 controls matched for age, sex, treatment group, and study site, was conducted after the completion of the CSPPT. Results: The median follow-up duration was 4.5 years. Among men, a significantly higher risk of first stroke (adjusted OR, 1.67; 95%CI: 1.01, 2.77) was found for those with plasma vitamin E ≥7.1 μg/mL (≥quartile 1) compared with those with plasma vitamin E < 7.1 μg/mL. Subgroup analyses further showed that the association between vitamin E (≥7.1 vs. <7.1 μg/mL) and first stroke in men was significantly stronger in non-drinkers (adjusted OR, 2.64; 95%CI: 1.41, 4.96), compared to current drinkers (adjusted OR, 0.84; 95% CI: 0.43, 1.66, P-interaction = 0.008). However, there was no significant association between plasma vitamin E and first stroke in women (P-interaction between sex and plasma vitamin E = 0.048). Conclusions: Among Chinese hypertensive patients, there was a statistically significant positive association between baseline plasma vitamin E and the risk of first stroke in men, but not in women. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00794885, Identifier: NCT00794885.

The apparent inverse association between dietary carotene intake and risk of cardiovascular mortality disappeared after adjustment for other cardioprotective dietary intakes: The Japan collaborative cohort study

BACKGROUND AND PURPOSE

An effect of dietary carotenes on risk of cardiovascular disease (CVD) is uncertain. We aimed to investigate whether the association between dietary carotenes intake and risk of CVD mortality will persist after controlling for the intakes of potential cardioprotective dietary factors that correlate with dietary alpha- and/or beta-carotenes.

METHODS AND RESULTS

We followed up a total of 58,646 Japanese between 1988 and 1990 and 2009. We used a food frequency questionnaire (FFQ) to determine the dietary intakes of carotenes, and estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) of CVD mortality in relation to carotene intake by the proportional hazard regression developed by David Cox. During 965,970 person-years of follow-up (median 19.3 years), we identified 3388 total CVD deaths. After adjusting for demographic and lifestyle factors, dietary intakes of alpha-carotene were significantly associated with the reduced risk of mortality from coronary heart disease (CHD); adjusted HR (95% CI) in the highest versus lowest quintiles of intake was 0.75 (0.58-0.96; P-trend = 0.02) and dietary intakes of beta-carotene were significantly associated with the reduced risk of mortality from CVD, CHD, and other CVD; adjusted HRs (95% CIs) were 0.88 (0.79-0.98; P-trend = 0.04), 0.78 (0.61-0.99; P-trend = 0.01), and 0.81 (0.67-0.98; P-trend = 0.04), respectively. However, after further adjusting for the dietary intakes of potassium, calcium, vitamins C, E, or K, these associations disappeared.

CONCLUSIONS

-Dietary alpha- and beta-carotene intakes were not associated with risk of CVD mortality after controlling for intakes of other potential cardioprotective nutrients.

The impact of plasma vitamin C levels on the risk of cardiovascular diseases and Alzheimer's disease: A Mendelian randomization study

BACKGROUND & AIMS

Previous observational studies have reported associations between plasma vitamin C levels, and cardiovascular diseases (CVDs) and Alzheimer's disease (AD); however, no conclusive results have been obtained. We conducted a Mendelian randomization (MR) study to investigate the causality of vitamin C on the risk of nine CVDs [including coronary artery disease (CAD), myocardial infarction (MI), atrial fibrillation (AF), heart failure (HF), stroke, ischemic stroke (IS), and IS subtypes] and Alzheimer's disease.

METHODS

Eleven single-nucleotide polymorphisms (SNPs) identified in a recent genome-wide meta-analysis (N = 52,018) were used as the instrumental variables for plasma vitamin C levels. The summary-level data for CVDs and AD were extracted from consortia and genome-wide association studies (GWAS). We performed MR analyses using the fixed-effects inverse-variance-weighted (IVW) method, weighted median, and MR-Egger approaches.

RESULTS

This MR study found suggestive evidence that genetic liability to higher vitamin C levels was associated with a lower risk of cardioembolic stroke [odds ratio (OR, presented per 1 standard deviation increase in plasma vitamin C levels) = 0.773; 95% confidence interval (CI), 0.623-0.959; P = 0.020] and AD (OR = 0.968; 95% CI, 0.946-0.991; P = 0.007) using the fixed-effects IVW method. Sensitivity analysis yielded directionally similar results. A null-association was observed between vitamin C and the other CVDs.

CONCLUSION

Our MR study provided suggestive evidence that higher vitamin C levels were casually associated with a decreased risk of cardioembolic stroke and AD. No evidence was observed to suggest that vitamin C affected the risk of CAD, MI, AF, HF, stroke, IS, large artery stroke, or small vessel stroke. However, well-designed studies are warranted to confirm these results and determine the underlying mechanisms of the causal links.

Sex difference in the association between plasma selenium and first stroke: a community-based nested case-control study

BACKGROUND

To date, there is no clearly defined association between plasma selenium levels and first stroke. We aimed to investigate the association between baseline plasma selenium and first stroke risk in a community-based Chinese population.

METHODS

Using a nested case-control study design, a total of 1255 first stroke cases and 1255 matched controls were analyzed. Participant plasma selenium concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS), and the association of plasma selenium with first stroke risk was estimated by conditional logistic regression models.

RESULTS

Overall, a non-linear negative association between plasma selenium and first total stroke and first ischemic stroke risks was found in males but not in females. Compared with participants with lower selenium levels (tertile 1-2, < 94.1 ng/mL), participants with higher selenium levels (tertile 3, ≥ 94.1 ng/mL) had significantly lower risks of first total stroke (OR 0.63; 95% CI 0.48, 0.83) and first ischemic stroke (OR 0.61; 95% CI 0.45, 0.83) in males but not in females with first total stroke (OR 0.92; 95% CI 0.69, 1.22) and first ischemic stroke (OR 0.89; 95% CI 0.65, 1.22). Furthermore, a stronger association between plasma selenium and first total stroke was found in males with higher vitamin E levels (≥ 13.5 μg/mL vs. < 13.5 μg/mL P-interaction = 0.007). No significant association was observed between plasma selenium and first hemorrhagic stroke risk in either males or females.

CONCLUSION

Our study indicated a significant, non-linear, negative association between plasma selenium and first stroke in males but not in females.

TRIAL REGISTRATION

ChiCTR1800017274 .

Antioxidants in smokers

Cigarette smoke (CS) is likely the most common preventable cause of human morbidity and mortality worldwide. Consequently, inexpensive interventional strategies for preventing CS-related diseases would positively impact health systems. Inhaled CS is a powerful inflammatory stimulus and produces a shift in the normal balance between antioxidants and oxidants, inducing oxidative stress in both the respiratory system and throughout the body. This enduring and systemic pro-oxidative state within the body is reflected by increased levels of oxidative stress and inflammation biomarkers seen in smokers. Smokers might benefit from consuming antioxidant supplements, or a diet rich in fruit and vegetables, which can reduce the CS-related oxidative stress. This review provides an overview of the plasma profile of antioxidants observable in smokers and examines the heterogeneous literature to elucidate and discuss the effectiveness of interventional strategies based on antioxidant supplements or an antioxidant-rich diet to improve the health of smokers. An antioxidant-rich diet can provide an easy-to-implement and cost-effective preventative strategy to reduce the risk of CS-related diseases, thus being one of the simplest ways for smokers to stay in good health for as long as possible. The health benefits attributable to the intake of antioxidants have been observed predominantly when these have been consumed within their natural food matrices in an optimal antioxidant-rich diet, while these preventive effects are rarely achieved with the intake of individual antioxidants, even at high doses.

Dietary and supplemental antioxidant intake and risk of major adverse cardiovascular events in older men: The concord health and ageing in men project

BACKGROUND AND AIMS

The role of antioxidant intake in cardiovascular disease remains inconclusive. This study evaluates the association between antioxidant intake and the risk of major adverse cardiovascular events (MACE) among older Australian men.

METHODS AND RESULTS

794 men aged ≥75 years participated in the 3rd wave of the Concord Health and Ageing in Men Project. Dietary adequacy of antioxidant intake was assessed by comparing participants' intake of vitamins A, E, C and zinc to the Nutrient Reference Values (NRV) for Australia. Attainment of NRVs of antioxidants was categorised into a dichotomised variable 'inadequate' (meeting≤2 of 4 antioxidants) or 'adequate' (meeting≥3 of 4 antioxidants). The usage of antioxidant supplements was assessed. The outcome measure was MACE. The composite MACE endpoint was defined as having one of the following: death, myocardial infarction, ischemic stroke, congestive cardiac failure (CCF), and revascularization during the period of observation. There was no significant association between dietary (HR: 1.03, 95% CI: 0.71, 1.48) or supplemental antioxidant intake (HR: 1.10, 95% CI: 0.75, 1.63) and overall MACE. However, a significant association was observed between inadequate antioxidant intake and CCF (HR: 1.32; 95% CI: 1.16, 1.50). The lowest quartile of zinc intake (<11.00 mg/d) was significantly associated with CCF (HR 2.36; 95% CI: 1.04, 5.34). None of the other antioxidants were significantly associated with CCF or other MACE components.

CONCLUSION

Inadequate dietary antioxidant intake, particularly zinc, is associated with increased risk of CCF in older Australian men but not associated with overall MACE.

Neuroprotective effects of Apium graveolens against focal cerebral ischemia occur partly via antioxidant, anti-inflammatory, and anti-apoptotic pathways

BACKGROUND

Stroke is a neurological disease caused by a sudden disturbance of cerebral blood flow to the brain, leading to loss of brain function. Recently, accumulating lines of evidence have suggested that dietary enrichment with nutritional antioxidants could reduce brain damage and improve cognitive function. In this study, we investigated the possible protective effects of Apium graveolens, a medicinal plant with putative neuroprotective activity, against oxidative-stress-related brain damage and brain damage due to inflammation induced by focal cerebral ischemia.

METHODS

Male adult Wistar rats were administered with an extract of A. graveolens orally 14 days before permanent occlusion of their right middle cerebral artery. The brain infarct volumes of rats in each group were determined by 2,3,5-triphenyltetrazolium chloride staining, and the density of neurons in the cortex and hippocampus of rats was determined by cresyl violet staining. The levels of malondialdehyde, catalase, glutathione peroxidase, and superoxide dismutase in the cerebral cortex and hippocampus of the rats were also quantified at the end of the study period.

RESULTS

Our results show that A. graveolens extract significantly decreased infarct volume and improved neuronal density in the cortex and hippocampus of rats receiving A. graveolens extract compared with those rats receiving no treatment. This neuroprotective effect was found to occur partly due to antioxidant, anti-inflammatory, and anti-apoptotic effects.

CONCLUSION

Our study demonstrates that A. graveolens helps to reduce the severity of cognitive damage caused by focal cerebral ischemia. © 2020 Society of Chemical Industry.

Intra-Individual Variation and Reliability of Biomarkers of the Antioxidant Defense System by Considering Dietary and Lifestyle Factors in Premenopausal Women

Epidemiological studies frequently rely on a single biomarker measurement to assess the relationship between antioxidant status and diseases. This bears an inherent risk for misclassification, if the respective biomarker has a high intra-individual variability. The present study investigates the intra-individual variation and reliability of enzymatic and non-enzymatic biomarkers of the antioxidant system in premenopausal women. Forty-four apparently healthy females provided three consecutive fasting blood samples in a four-week rhythm. Analyzed blood biomarkers included Trolox equivalent antioxidant capacity (TEAC), catalase, glutathione peroxidase, glutathione, vitamin C, bilirubin, uric acid, coenzyme Q10, tocopherols, carotenoids and retinol. Intra- and inter-individual variances for each biomarker were estimated before and after adjusting for relevant influencing factors, such as diet, lifestyle and use of contraceptives. Intraclass correlation coefficient (ICC), index of individuality, reference change value and number of measurements needed to confine attenuation in regression coefficients were calculated. Except for glutathione and TEAC, all biomarkers showed a crude ICC ≥ 0.50 and a high degree of individuality indicating that the reference change value is more appropriate than population-based reference values to scrutinize and classify intra-individual changes. Apart from glutathione and TEAC, between 1 and 9 measurements were necessary to reduce attenuation in regression coefficients to 10%. The results indicate that the majority of the assessed biomarkers have a fair to very good reliability in healthy premenopausal women, except for glutathione and TEAC. To assess the status of the antioxidant system, the use of multiple measurements and biomarkers is recommended.

Effects of vitamin E on neurodegenerative diseases: an update

Vitamin E deficiency is associated with many neurological problems. Although the mechanisms of vitamin E action in neurodegenerative diseases are not clear, there are many possible mechanisms. Examples of such mechanisms are the protective effects of vitamin E against oxidative stress damage and its suppressive role in the expression of many genes involved in the development of neurodegeneration. Many studies have evaluated the relationship between vitamin E intake or vitamin E levels in body fluids and neurodegenerative diseases. Some studies concluded that vitamin E can play a protective role in neurodegeneration with respect to diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), stroke and amyotrophic lateral sclerosis (ALS). Vitamin E supplementation was also associated with risk factors for some neurodegenerative diseases. In this review, we discuss the possible effects of vitamin E on the development and course of AD, PD, stroke and ALS, and the potential mechanisms involved.

Vitamin E deficiency is associated with many neurological problems. Although the mechanisms of vitamin E action in neurodegenerative diseases are not clear, there are many possible mechanisms. Examples of such mechanisms are the protective effects of vitamin E against oxidative stress damage and its suppressive role in the expression of many genes involved in the development of neurodegeneration. Many studies have evaluated the relationship between vitamin E intake or vitamin E levels in body fluids and neurodegenerative diseases. Some studies concluded that vitamin E can play a protective role in neurodegeneration with respect to diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), stroke and amyotrophic lateral sclerosis (ALS). Vitamin E supplementation was also associated with risk factors for some neurodegenerative diseases. In this review, we discuss the possible effects of vitamin E on the development and course of AD, PD, stroke and ALS, and the potential mechanisms involved.

Overview of Meta-Analyses: The Impact of Dietary Lifestyle on Stroke Risk

A stroke is one of the most prevalent cardiovascular diseases worldwide, both in high-income countries and in medium and low-medium income countries. The World Health Organization's (WHO) report on non-communicable diseases (NCDs) indicates that the highest behavioral risk in NCDs is attributable to incorrect nutrition. The objective of our work is to present an overview of meta-analyses that have investigated the impact of different foods and/or drinks in relationship with the risk of stroke events (ischemic/hemorrhagic). The papers to be included in the overview were found in MEDLINE, EMBASE, Scopus, Clinicaltrials.gov, Web of Science, and Cochrane Library and were selected according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) flow chart. Quality assessment were made according to the AMSTAR 2 scale. This overview shows that all primary studies came from countries with high income levels. This evidence shows that many countries are not represented. Therefore, different lifestyles, ethnic groups, potentially harmful or virtuous eating habits are not reported. It is important to underline how the choose of foods may help reduce the risk of cardiovascular diseases and stroke in particular.

Approaches and Methods to Measure Oxidative Stress in Clinical Samples: Research Applications in the Cancer Field

Reactive oxygen species (ROS) are common by-products of normal aerobic cellular metabolism and play important physiological roles in intracellular cell signaling and homeostasis. The human body is equipped with antioxidant systems to regulate the levels of these free radicals and maintain proper physiological function. However, a condition known as oxidative stress (OS) occurs, when ROS overwhelm the body's ability to readily detoxify them. Excessive amounts of free radicals generated under OS conditions cause oxidative damage to proteins, lipids, and nucleic acids, severely compromising cell health and contributing to disease development, including cancer. Biomarkers of OS can therefore be exploited as important tools in the assessment of disease status in humans. In the present review, we discuss different approaches used for the evaluation of OS in clinical samples. The described methods are limited in their ability to reflect on OS only partially, revealing the need of more integrative approaches examining both pro- and antioxidant reactions with higher sensitivity to physiological/pathological alternations. We also provide an overview of recent findings of OS in patients with different types of cancer. Identification of OS biomarkers in clinical samples of cancer patients and defining their roles in carcinogenesis hold great promise in promoting the development of targeted therapeutic approaches and diagnostic strategies assessing disease status. However, considerable data variability across laboratories makes it difficult to draw general conclusions on the significance of these OS biomarkers. To our knowledge, no adequate comparison has yet been performed between different biomarkers and the methodologies used to measure them, making it difficult to conduct a meta-analysis of findings from different groups. A critical evaluation and adaptation of proposed methodologies available in the literature should therefore be undertaken, to enable the investigators to choose the most suitable procedure for each chosen biomarker.

Plasma retinol and the risk of first stroke in hypertensive adults: a nested case-control study

Background

Identification of novel risk factors is needed to further lower stroke risk. Data concerning the association between plasma retinol concentrations and the risk of stroke are limited.

Objectives

We aimed to evaluate the effect of plasma retinol on the risk of first stroke and to examine any possible effect modifiers in hypertensive patients.

Methods

The study sample population was drawn from the China Stroke Primary Prevention Trial (CSPPT), using a nested case-control design, including 620 cases with first stroke and 620 matched controls. In the CSPPT, a total of 20,702 hypertensive patients were randomly assigned to a double-blind, daily treatment with either 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. The median treatment duration was 4.5 y.

Results

There was a significant inverse association between plasma retinol and the risk of first stroke (per 10-μg/dL increment; OR: 0.92; 95% CI: 0.86, 0.97) and first ischemic stroke (OR: 0.92; 95% CI: 0.86, 0.98). When retinol was assessed as quartiles, significantly lower risks of first stroke (OR: 0.64; 95% CI: 0.46, 0.88) and first ischemic stroke (OR: 0.67; 95% CI: 0.46, 0.96) were found in participants in quartiles 2-4 compared with those in quartile 1. Furthermore, a stronger inverse association between plasma retinol and first stroke was observed in participants with baseline total homocysteine (<10 compared with ≥10 μmol/L; P-interaction = 0.049). However, plasma retinol had no significant effect on first hemorrhagic stroke (per 10-μg/dL increment; OR: 0.98; 95% CI: 0.79, 1.18).

Conclusions

Our data showed a significant inverse association between plasma retinol and the risk of first stroke among Chinese hypertensive adults. This study was registered at clinicaltrials.gov as NCT00794885.

Dietary Intake of Anti-Oxidant Vitamins A, C, and E Is Inversely Associated with Adverse Cardiovascular Outcomes in Chinese-A 22-Years Population-Based Prospective Study

Background: Conflicting and population-dependent findings have been reported from epidemiological studies on the associations of dietary intake of anti-oxidant vitamins with cardiovascular events. We investigated the prospective relationship between dietary intake of anti-oxidant vitamins and incident adverse cardiovascular outcomes amongst Hong Kong Chinese. Methods: In this prospective population-based study, baseline dietary intake of anti-oxidant vitamins (A, C, and E) were assessed using a food frequency questionnaire in 875 Chinese participants from the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS) in 1995–1996. The adjusted hazard ratio (HR) of incident adverse cardiovascular outcomes, defined as the first recorded diagnosis of cardiovascular deaths, non-fatal myocardial infarction or non-fatal stroke, and coronary or other arterial revascularizations, was calculated per unit intake of each vitamin using multivariable Cox regression. Results: Over a median follow-up of 22 years, 85 participants (9.7%) developed adverse cardiovascular outcomes. Dietary intakes of vitamin A, C, and E were independently and inversely associated with incident adverse cardiovascular outcomes (HR 0.68, 95%CI 0.53–0.88, p = 0.003 for vitamin A; HR 0.66, 95%CI 0.52–0.85, p = 0.001 for vitamin C; and HR 0.57, 95%CI 0.38–0.86, p = 0.017 for vitamin E) after adjustments for conventional cardiovascular risk factors at baseline. Conclusions: Dietary intakes of anti-oxidant vitamins A, C, and E reduced the risk of adverse cardiovascular outcomes in Hong Kong Chinese.

Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective studies

Background

High dietary intake or blood concentrations (as biomarkers of dietary intake) of vitamin C, carotenoids, and vitamin E have been associated with reduced risk of cardiovascular disease, cancer, and mortality, but these associations have not been systematically assessed.

Objective

We conducted a systematic review and meta-analysis of prospective studies of dietary intake and blood concentrations of vitamin C, carotenoids, and vitamin E in relation to these outcomes.

Design

We searched PubMed and Embase up to 14 February 2018. Summary RRs and 95% CIs were calculated with the use of random-effects models.

Results

Sixty-nine prospective studies (99 publications) were included. The summary RR per 100-mg/d increment of dietary vitamin C intake was 0.88 (95% CI: 0.79, 0.98, I2 = 65%, n = 11) for coronary heart disease, 0.92 (95% CI: 0.87, 0.98, I2 = 68%, n = 12) for stroke, 0.89 (95% CI: 0.85, 0.94, I2 = 27%, n = 10) for cardiovascular disease, 0.93 (95% CI: 0.87, 0.99, I2 = 46%, n = 8) for total cancer, and 0.89 (95% CI: 0.85, 0.94, I2 = 80%, n = 14) for all-cause mortality. Corresponding RRs per 50-μmol/L increase in blood concentrations of vitamin C were 0.74 (95% CI: 0.65, 0.83, I2 = 0%, n = 4), 0.70 (95% CI: 0.61, 0.81, I2 = 0%, n = 4), 0.76 (95% CI: 0.65, 0.87, I2 = 56%, n = 6), 0.74 (95% CI: 0.66, 0.82, I2 = 0%, n = 5), and 0.72 (95% CI: 0.66, 0.79, I2 = 0%, n = 8). Dietary intake and/or blood concentrations of carotenoids (total, β-carotene, α-carotene, β-cryptoxanthin, lycopene) and α-tocopherol, but not dietary vitamin E, were similarly inversely associated with coronary heart disease, stroke, cardiovascular disease, cancer, and/or all-cause mortality.

Conclusions

Higher dietary intake and/or blood concentrations of vitamin C, carotenoids, and α-tocopherol (as markers of fruit and vegetable intake) were associated with reduced risk of cardiovascular disease, total cancer, and all-cause mortality. These results support recommendations to increase fruit and vegetable intake, but not antioxidant supplement use, for chronic disease prevention.