Press releases Monday 13 June to Friday 17 July 2009
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(1) Better estimates of flu virus severity needed, say experts
(2) Young Scots from deprived backgrounds more likely to die from heart disease
(1) Better estimates of flu virus severity needed, say experts
(Assessing the severity of the novel influenza A (H1N1) pandemic)
http://www.bmj.com/cgi/doi/10.1136/bmj.b2840
Accurate estimates of the severity of the new H1N1 virus, and in particular how many deaths might arise over the course of the pandemic, are central to healthcare planning over the coming months, say experts in a paper published on bmj.com today.
They will also help to influence decisions on whether to implement social distancing measures such as school closures.
At first sight, the data appear to imply that this new Influenza A (H1N1) virus is relatively mild, with case fatality ratios (the total number of deaths due to the disease divided by the total number of cases) around 0.5%, similar to the upper range of that seen for seasonal influenza, and relatively low hospitalisation rates.
However severity appears to vary substantially between countries and fatal cases have been much younger than for seasonal influenza.
So researchers at Imperial College London analysed the difficulties in assessing the severity of the new virus. They report that in most infectious diseases there is a risk of bias towards diagnosis of more severe and hospitalised cases, which overestimates the case fatality ratio.
In contrast, some deaths caused by flu might not be recognised as such, as flu infections can temporarily increase the risk of vascular death, such as heart attacks and strokes. This causes an underestimation of the case fatality ratio.
Another important source of bias arises from the time delay between disease onset and death, which in the early phase of an epidemic can lead to an underestimate of the case fatality ratio, they add.
In order to get a clear picture of the severity of the H1N1 virus, it is vital to take these and other factors into account, say the authors. They propose study designs and statistical analysis methods to improve our ability to obtain reliable case fatality ratios.
Critically, they will ensure that any changes in the virulence of the virus are rapidly detected so that mitigation policies are applied appropriately, they conclude.
Dr Tini Garske, lead author of the study from the Medical Research Council (MRC) Centre for Outbreak Analysis & Modelling at Imperial College London, said: "Accurately predicting the severity of this swine flu pandemic is a very tricky business, and our research shows that this can only be achieved if data is collected according to well designed study protocols and analysed in a more sophisticated way than is frequently being performed at present.
"If we fail to get an accurate prediction of severity, we will not be providing healthcare planners, doctors and nurses, with the information that they need to ensure they are best prepared to fight the pandemic as we head into the flu season this autumn."
Contact:
Via Lucy Goodchild, Imperial College Press Office, London, UK
Email: lucy.goodchild@imperial.ac.uk
(2) Research: Coronary heart disease mortality among young adults in Scotland in relation to social inequalities: time trend study
(Research: Coronary heart disease mortality among young adults in Scotland in relation to social inequalities: time trend study)
http://www.bmj.com/cgi/doi/10.1136/bmj.b2613
(Editorial: Why has mortality from coronary heart disease in young adults levelled off?)
http://www.bmj.com/cgi/doi/10.1136/bmj.b2515
In Scotland, young men and women (ages 35-44) from socially deprived groups are around six times more likely to die from heart disease than the most affluent individuals in the same age range, according to research published on bmj.com today.
The results reveal that this disparity diminishes with age but only disappears for people who are 85 or over.
The number of people dying from heart disease in Scotland has halved in the last two decades but the country still has some of the highest deaths in Europe and globally, says the study.
And while the overall number of deaths from heart disease in Scotland is decreasing, this decline is slowing down in young adults, especially those from deprived groups, say the authors.
The research team, led by Professor Simon Capewell, a clinical epidemiologist from the University of Liverpool, argue that the slow down is not due to poor treatment provision but is linked to unhealthy social environments and high risk behaviour like smoking and poor diet. They maintain that these factors are more common in individuals from deprived backgrounds and that this study reveals major social inequalities in Scotland.
The authors surveyed death rates from heart disease in Scotland from 1986 to 2006. The study included men and women aged 35 and over.
They conclude that: "These mortality changes reflect social gradients in unhealthy behaviour, lifestyle and circumstances resulting in poor diet and high tobacco consumption leading to unfavourable levels of major coronary heart disease risk factors. These inequalities are persisting in spite of the widespread and constant health promotion and health prevention initiatives, which suggests substantial and continuing barriers to healthy changes."
In an accompanying editorial, Professor Alastair Leyland, from the Medical Research Council in Glasgow, agrees that it is extremely worrying that the slowing of improvements at younger ages is confined to the most deprived groups and asks why these young Scots are "not sharing in the benefits seen by others?"
Given health promotion programmes have had limited success, Leyland argues that perhaps it is time "to tackle the social inequalities themselves - unequal distribution of power, money, resources and life chances."
Contacts:
Research: Professor Simon Capewell, Division of Public Health, University of Liverpool, Liverpool, UK
Email: capewell@liverpool.ac.uk
Editorial: Professor Alastair Leyland, Senior Research Scientist, MRC Social and Public Health Sciences Unit, Glasgow, Scotland, UK
Email: a.leyland@sphsu.mrc.ac.uk
For more information please contact:
Emma Dickinson
Tel: +44 (0)20 7383 6529
Email: edickinson@bmj.com
Press Office telephone : 020 7383 6254 (Weekdays : 0900hrs - 1800hrs)
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and from:
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