RoB 2: a revised tool for assessing risk of bias in randomised trials

Assessment of risk of bias is regarded as an essential component of a systematic review on the effects of an intervention. The most commonly used tool for randomised trials is the Cochrane risk-of-bias tool. We updated the tool to respond to developments in understanding how bias arises in randomised trials, and to address user feedback on and limitations of the original tool

Prevalence of cardiovascular risk factors in a middle-income country and estimated cost of a treatment strategy

BACKGROUND: We assessed the prevalence of risk factors for cardiovascular disease (CVD) in a middle-income country in rapid epidemiological transition and estimated direct costs for treating all individuals at increased cardiovascular risk, i.e. following the so-called "high risk strategy". METHODS: Survey of risk factors using an age- and sex-stratified random sample of the population of Seychelles aged 25–64 in 2004. Assessment of CVD risk and treatment modalities were in line with international guidelines. Costs are expressed as US$per capita per year. RESULTS: 1255 persons took part in the survey (participation rate of 80.2$45.6, i.e. $11.2 for high blood pressure,$3.8 for diabetes, and $30.6 for dyslipidemia (using generic drugs except for hypercholesterolemia). Cost for minimal follow-up medical care and laboratory tests amounted to$22.6. CONCLUSION: High prevalence of major risk factors was found in a rapidly developing country and costs for treatment needed to reduce risk factors in all high-risk individuals exceeded resources generally available in low or middle income countries. Our findings emphasize the need for affordable cost-effective treatment strategies and the critical importance of population strategies aimed at reducing risk factors in the entire population

What Is Stochastic Resonance? Definitions, Misconceptions, Debates, and Its Relevance to Biology

Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations—e.g., random noise—cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being “suboptimal”. Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the “neural code”. Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise—via stochastic resonance or otherwise—than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing “noise benefits”, and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology

Natural gas fueled compression ignition engine performance and emissions maps with diesel and RME pilot fuels

When natural gas is port/manifold injected into a compression ignition engine, the mixture of air and the natural gas is compressed during the compression stroke of the engine. Due to the difference in the values of specific heat capacity ratio between air and natural gas, the temperature and pressure at the time of pilot fuel injection are different when compared to a case where only air is compressed. Also, the presence of natural gas affects the peak in-cylinder (adiabatic flame) temperature. This significantly affects the performance as well as emissions characteristics of natural gas based dual fueling in CI engine. Natural gas has been extensively tested in a single cylinder compression ignition engine to obtain performance and emissions maps.Two pilot fuels, diesel and RME, have been used to pilot natural gas combustion. The performance of the two liquid fuels used as pilots has also been assessed and compared. Tests were conducted at 48 different operating conditions (six different speeds and eight different power output conditions for each speed) for single fueling cases. Both the diesel and RME based single fueling cases were used as baselines to compare the natural gas based dual fueling where data was collected at 36 operating conditions (six different speeds and six different power output conditions for each speed). Performance and emissions characteristics were mapped on speed vs brake power plots. The thermal efficiency values of the natural gas dual fueling were lower when compared to the respective pilot fuel based single fueling apart from the highest powers. The effect of engine speed on volumetric efficiency in case of the natural gas based dual fueling was significantly different from what was observed with the single fueling. Contours of specific NOX for diesel and RME based single fueling differ significantly when these fuels were used to pilot natural gas combustion. For both of the single fueling cases, maximum specific NOX were centered at the intersection of medium speeds and medium powers and they decrease in all directions from this region of maximum values. On the other hand, an opposite trend was observed with dual fueling cases where minimum specific NOX were observed at the center of the map and they increase in all direction from this region of minimum NOX. RME piloted specific NOX at the highest speeds were the only exception to this trend. Higher specific HC and lower specific CO2 emissions were observed in case of natural gas based dual fueling. The emissions were measured in g/MJ of engine power

Sex-specific relevance of diabetes to occlusive vascular and other mortality: Meta-analysis of individual data from 68 prospective studies with 77,000 deaths among 1 million adults

Background Several studies have shown that diabetes confers a higher relative risk of vascular mortality among women compared to men, but whether this exists across age groups and within levels of other risk factors is uncertain. Methods Individual data were obtained on 980,793 adults in 68 prospective studies. Cox models assessed the relevance of diabetes to occlusive vascular mortality (ischaemic heart disease, ischaemic stroke or other atherosclerotic deaths) by age, sex and other major vascular risk factors, and were also used to assess whether the associations of blood pressure, total cholesterol and body-mass index (BMI) to occlusive vascular mortality are modified by diabetes. Results During 9.8 million person-years of follow-up at ages 35-89 years, 19,686/76,965 (26%) deaths were attributed to occlusive vascular disease. Even after controlling for major vascular risk factors, diabetes conferred a doubling in occlusive vascular mortality risk among men (death rate ratio, RR=2·10; 95% CI 1·97-2·24) and a tripling among women (3·00; 2·71-3·33). RRs were more extreme at younger than at older ages (2·60 [2·30-2·94] at ages 35-59 versus 2·01 [1·85-2·19] at ages 70-89, ptrend=0·0001), and, at all ages, were more extreme in women than in men. So, among women aged 35-59, diabetes conferred nearly 6-fold increased risk. Because the occlusive vascular mortality rates at any given age were generally higher among men than women, the absolute excess mortality rates associated with diabetes were similar for men versus women: 0.08 %/year (0.05-0.10) versus 0.05 %/year (0.03-0.07) at ages 40-59; and 0.91 %/year (0.77-1.05) versus 1.08 %/year (0.84-1.08) at ages 70-89, respectively. Total cholesterol, blood pressure and BMI each displayed continuous log-linear associations with occlusive vascular mortality that were similar among those with and without diabetes. Interpretation Independently of other major vascular risk factors, diabetes substantially increased vascular risk in both men and women. Lifestyle changes (to reduce smoking and obesity) and wide use of cost-effective medications (especially statins and BP-lowering drugs) are important among both men and women with diabetes, but may not reduce the relative excess risk of occlusive vascular disease in women with diabetes.</p

Mobilising a disadvantaged community for a cardiovascular intervention : designing PRORIVA in Yogyakarta, Indonesia

INTRODUCTION: Cardiovascular disease (CVD) is a burden for developing countries, yet few CVD intervention studies have been conducted in developing countries such as Indonesia. This paper outlines the process of designing a community intervention programme to reduce CVD risk factors, and discusses experiences with regard to design issues for a small-scale intervention. DESIGN PROCESS: THE DESIGN PROCESS FOR THE PRESENT COMMUNITY INTERVENTION CONSISTED OF SIX STAGES: (1) a baseline risk factor survey, (2) design of a small-scale intervention by using both baseline survey and qualitative data, (3) implementation of the small-scale intervention, (4) evaluation of the small-scale intervention and design of a broader CVD intervention in the Yogyakarta municipality, (5) implementation of the broader intervention and (6) evaluation of the broader CVD intervention. According to the baseline survey, 60% of the men were smokers, more than 30% of the population had insufficient fruit and vegetable intake and more than 30% of the population were physically inactive, this is why a small-scale population intervention approach was chosen, guided both by the findings in the quantitative and the qualitative study. EXPERIENCES: A quasi-experimental study was designed with a control group and pre- and post-testing. In the small-scale intervention, two sub-districts were selected and randomly assigned as intervention and control areas. Within them, six intervention settings (two sub-villages, two schools and two workplaces) and three control settings (a sub-village, a school and a workplace) were selected. Health promotion activities targeting the whole community were implemented in the intervention area. During the evaluation, more activities were performed in the low socioeconomic status sub-village and at the civil workplace.This study was supported by a grant from the Provincial Health Office of Yogyakarta Special Regency, Indonesia, by a scholarship based on a donation from the Swedish Centre Party to Umea International School of Public Health, Umea, Sweden and Umea Centre for Global Health Research.</p

Do women exhibit greater differences in established and novel risk factors between diabetes and non-diabetes than men? The British Regional Heart Study and British Women’s Heart Health Study

&lt;p&gt;&lt;b&gt;Aims/hypothesis:&lt;/b&gt; Type 2 diabetes is associated with greater relative risk of CHD in women than in men, which is not fully explained by conventional cardiovascular risk factors. We assessed whether cardiovascular risk factors including more novel factors such as markers of insulin resistance, inflammation, activated coagulation and endothelial dysfunction differ more between diabetic and non-diabetic women than between diabetic and non-diabetic men, and the role of insulin resistance.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; A cross-sectional study of non-diabetic and diabetic men and women (n=7,529) aged 60–79 years with no previous myocardial infarction who underwent an examination was conducted. Measurements of anthropometry, blood pressure and fasting measurements of lipids, insulin, glucose and haemostatic and inflammatory markers were taken.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; Non-diabetic women tended to have more favourable risk factors and were less insulin resistant than nondiabetic men, but this was diminished in the diabetic state. Levels of waist circumference, BMI, von Willebrand factor(VWF), WBC count, insulin resistance (HOMA-IR), diastolic blood pressure, HDL-cholesterol, tissue plasminogen activator (t-PA) and factor VIII differed more between diabetic and non-diabetic women than between diabetic and non-diabetic men (test for diabetes×sex interaction p&#60;0.05). The more adverse effect of diabetes on these risk markers in women was associated with, and thereby largely attenuated by, insulin resistance.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions/interpretation:&lt;/b&gt; The greater adverse influence of diabetes per se on adiposity and HOMA-IR and downstream blood pressure, lipids, endothelial dysfunction and systemic inflammation in women compared with men may contribute to their greater relative risk of coronary heart disease.&lt;/p&gt