Vitamin C supplementation for the primary prevention of cardiovascular disease.

BACKGROUND: Vitamin C is an essential micronutrient and powerful antioxidant. Observational studies have shown an inverse relationship between vitamin C intake and major cardiovascular events and cardiovascular disease (CVD) risk factors. Results from clinical trials are less consistent. OBJECTIVES: To determine the effectiveness of vitamin C supplementation as a single supplement for the primary prevention of CVD. SEARCH METHODS: We searched the following electronic databases on 11 May 2016: the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library; MEDLINE (Ovid); Embase Classic and Embase (Ovid); Web of Science Core Collection (Thomson Reuters); Database of Abstracts of Reviews of Effects (DARE); Health Technology Assessment Database and Health Economics Evaluations Database in the Cochrane Library. We searched trial registers on 13 April 2016 and reference lists of reviews for further studies. We applied no language restrictions. SELECTION CRITERIA: Randomised controlled trials of vitamin C supplementation as a single nutrient supplement lasting at least three months and involving healthy adults or adults at moderate and high risk of CVD were included. The comparison group was no intervention or placebo. The outcomes of interest were CVD clinical events and CVD risk factors. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion, abstracted the data and assessed the risk of bias. MAIN RESULTS: We included eight trials with 15,445 participants randomised. The largest trial with 14,641 participants provided data on our primary outcomes. Seven trials reported on CVD risk factors. Three of the eight trials were regarded at high risk of bias for either reporting or attrition bias, most of the 'Risk of bias' domains for the remaining trials were judged as unclear, with the exception of the largest trial where most domains were judged to be at low risk of bias.The composite endpoint, major CVD events was not different between the vitamin C and placebo group (hazard ratio (HR) 0.99, 95% confidence interval (CI) 0.89 to 1.10; 1 study; 14,641 participants; low-quality evidence) in the Physicians Health Study II over eight years of follow-up. Similar results were obtained for all-cause mortality HR 1.07, 95% CI 0.97 to 1.18; 1 study; 14,641 participants; very low-quality evidence, total myocardial infarction (MI) (fatal and non-fatal) HR 1.04 (95% CI 0.87 to 1.24); 1 study; 14,641 participants; low-quality evidence, total stroke (fatal and non-fatal) HR 0.89 (95% CI 0.74 to 1.07); 1 study; 14,641 participants; low-quality evidence, CVD mortality HR 1.02 (95% 0.85 to 1.22); 1 study; 14,641 participants; very low-quality evidence, self-reported coronary artery bypass grafting (CABG)/percutaneous transluminal coronary angioplasty (PTCA) HR 0.96 (95% CI 0.86 to 1.07); 1 study; 14,641 participants; low-quality evidence, self-reported angina HR 0.93 (95% CI 0.84 to 1.03); 1 study; 14,641 participants; low-quality evidence.The evidence for the majority of primary outcomes was downgraded (low quality) because of indirectness and imprecision. For all-cause mortality and CVD mortality, the evidence was very low because more factors affected the directness of the evidence and because of inconsistency.Four studies did not state sources of funding, two studies declared non-commercial funding and two studies declared both commercial and non-commercial funding. AUTHORS' CONCLUSIONS: Currently, there is no evidence to suggest that vitamin C supplementation reduces the risk of CVD in healthy participants and those at increased risk of CVD, but current evidence is limited to one trial of middle-aged and older male physicians from the USA. There is limited low- and very low-quality evidence currently on the effect of vitamin C supplementation and risk of CVD risk factors.

Predictors of Physician Recommendation for Ethically Controversial Medical Procedures: Findings from an Exploratory National Survey of American Muslim Physicians.

Physician religiosity can influence their ethical attitude toward medical procedures and can thereby impact healthcare delivery. Using a national survey of American Muslim physicians, we explored the association between physician recommendation of three controversial medical procedures--tubal ligation, abortion, and porcine-based vaccine--and their (1) religiosity, (2) utilization of bioethics resources, and (3) perception of whether the procedure was a medical necessity and if the scenario represented a life threat. Generally, multivariate models found that physicians who read the Qur'an more often as well as those who perceived medical necessity and/or life threat had a higher odds recommending the procedures, whereas those who sought Islamic bioethical guidance from Islamic jurists (or juridical councils) more often had a lower odds. These associations suggest that the bioethical framework of Muslim physicians is influenced by their reading of scripture, and the opinions of Islamic jurists and that these influences may, paradoxically, be interpreted to be in opposition over some medical procedures.

Vitamin K for the primary prevention of cardiovascular disease.

BACKGROUND: A deficiency in vitamin K has been associated with increased calcium deposition and coronary artery calcification, which may lead to cardiovascular disease. OBJECTIVES: To determine the effectiveness of vitamin K supplementation as a single nutrient supplement for the primary prevention of cardiovascular disease. SEARCH METHODS: We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 8 of 12, 2014); MEDLINE (Ovid, 1946 to September week 2 2014); EMBASE Classic + EMBASE (Ovid, 1947 to September 18 2014); Science Citation Index Expanded (SCI-EXPANDED) and Conference Proceedings Citation Index, Science (CPCI-S) (both 1990 to 17 September 2014) on Web of Science (Thomson Reuters); Database of Abstracts of Reviews of Effects (DARE); Health Technology Assessment Database and Health Economics Evaluations Database (Issue 3 of 4, 2014). We searched trial registers and reference lists of reviews for further studies. We applied no language restrictions. SELECTION CRITERIA: We included randomised controlled trials of vitamin K supplementation as a single nutrient supplement, lasting at least three months, and involving healthy adults or adults at high risk of cardiovascular disease. The comparison group was no intervention or placebo. The outcomes of interest were cardiovascular disease clinical events and cardiovascular disease risk factors. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion, abstracted the data and assessed the risk of bias. MAIN RESULTS: We included only one small trial (60 participants randomised) which overall was judged to be at low risk of bias. The study examined two doses of menaquinone (vitamin K2) over 3 months in healthy participants aged 40 to 65 years. The primary focus of the trial was to examine the effects of menaquinone (subtype MK7) on different matrix Gla proteins (MGP - vitamin K dependent proteins in the vessel wall) at different doses, but the authors also reported blood pressure and lipid levels. The trial did not report on our primary outcomes (cardiovascular disease clinical events) as it was small, short term and conducted in healthy participants.In terms of cardiovascular disease risk factors, no effects were seen for vitamin K2 on blood pressure or lipid levels, although the trial was small and findings are limited. The trial did not report any of our other secondary outcomes. AUTHORS' CONCLUSIONS: The very limited results of this review highlight the lack of evidence currently available to determine the effectiveness of vitamin K supplementation for the primary prevention of cardiovascular disease, and demonstrate the need for further high quality trials in this area.

Exploring the responsiveness of public and private hospitals in lagos, Nigeria.

According to the World Health Report 2000, health system responsiveness is proposed as one of the three key objectives of any health system. This multi-domain concept describes how well a health system responds to the expectations of their users concerning the non-health enhancing aspects of care. In this study we aim to compare the levels of responsiveness experienced by users of private and publicly managed hospitals in Nigeria, and through these insights, to propose recommendations on how to improve performance on this measure. This quantitative, cross-sectional study uses a questionnaire that is adapted from two responsiveness surveys designed by the World Health Organization (WHO). Researchers collected responses from 520 respondents from four hospitals in Lagos, Nigeria. Analysis of the data using statistical techniques found that significant differences exist between the performance of public and private hospitals on certain domains of responsiveness, with privately operated hospitals performing better where differences exist. Users of private hospitals also reported a higher level of overall satisfaction. Private hospitals were found to perform particularly better on the domains of dignity, waiting times, and travel times. These findings have implications for the management of public hospitals in focusing their efforts on improving their performance in low scoring domains. Performance in these hospitals can be improved by emphasis on staff training and demand management.