News Release

Lowering blood pressure, cholesterol and blood sugar could halve obesity-related risk of heart disease

Peer-Reviewed Publication

Imperial College London

Controlling blood pressure, cholesterol, and blood glucose may substantially reduce the risk of heart disease and stroke associated with being overweight or obese.

A pooled analysis of 97 prospective studies from around the world found that the increased risk of heart disease or stroke in overweight and obese people is partly because their weight increases their chances of having high blood pressure, high cholesterol and high blood glucose.

The study, by a worldwide research consortium led by a team from Harvard School of Public Health (HSPH), Imperial College London, and the University of Sydney, covered a total of 1.8 million participants. The findings are published in The Lancet.

Worldwide, obesity has nearly doubled since 1980, according to a previous study by the research team, and more than 1.4 billion adults aged 20 and older are overweight or obese. Being overweight increases one's risk of heart disease and stroke — the leading causes of death worldwide — diabetes, and several types of cancer. The researchers had also previously estimated that 3.4 million annual deaths are due to overweight and obesity.

There has been debate over whether excess weight causes heart disease and stroke through effects on other risk factors, particularly blood pressure, cholesterol, and glucose, and whether treatments that address these factors can offset the risks of being overweight.

The study found that high blood pressure, serum cholesterol, and blood glucose explain up to half of the increased risk of heart disease and three quarters of the increased risk of stroke among overweight or obese people. High blood pressure poses the biggest risk of the three metabolic factors examined, accounting for 31 per cent of the increased risk of heart disease and 65 per cent of the increased risk of stroke.

"Our results show that the harmful effects of being overweight or obese on heart disease and stroke partly occur by increasing blood pressure, serum cholesterol and blood glucose. Therefore, if we control these risk factors, for example through better diagnosis and treatment of hypertension, we can prevent some of the harmful effects of being overweight or obese," said senior author Goodarz Danaei, HSPH assistant professor of global health.

Co-author Professor Majid Ezzati, from the School of Public Health at Imperial College London, said: "Controlling hypertension, cholesterol, and diabetes through medication is useful, but not enough to offset the harms of overweight and obesity. So we need to need to find creative approaches that can curb and reverse the global obesity epidemic."

Professor Stephen Hill, Chair of the Medical Research Council's Molecular and Cellular Medicine Board, which part-funded the work, said: "Large, long-term population studies like this one are a very powerful tool, allowing researchers to disentangle individual factors and understand how they each contribute to our risk of disease. It's interesting that, even when blood pressure, blood sugar and cholesterol are brought under control, obese individuals are still at a higher risk of heart attack and stroke. This suggests that other factors might be at play, which is likely to be of interest for future research into the consequences of obesity."

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Other HSPH authors included Yuan Lu, doctoral candidate in the Department of Global Health and Population, Eric Rimm, associate professor in the Departments of Epidemiology and Nutrition, and Kaveh Hajifathalian, postdoctoral research fellow, Department of Global Health and Population.

Funding for the study came from the UK Medical Research Council; the National Institute for Health Research Imperial Biomedical Research Centre; the US National Institutes of Health; the Lown Scholars in Residence Program on cardiovascular disease prevention; and from a Harvard Global Health Institute Doctoral Research Grant.

For more information please contact:

Sam Wong
Research Media Officer
Imperial College London
Email: sam.wong@imperial.ac.uk
Tel: +44(0)20 7594 2198
Out of hours duty press officer: +44(0)7803 886 248

Todd Datz
Director of News and Online Communications
Harvard School of Public Health
Tel: +1 617-432-8413
tdatz@hsph.harvard.edu

Notes to editors

1. "Metabolic mediators of the effect of body mass index, overweight and obesity on coronary heart disease and stroke: Pooled analysis of 97 prospective cohorts with 1.8 million participants," Yuan Lu, Kaveh Hajifathalian, Majid Ezzati, Mark Woodward, Eric B. Rimm, and Goodarz Danaei, The Lancet, 22 November 2013.

2. About Imperial College London

Consistently rated amongst the world's best universities, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 14,000 students and 6,000 staff of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and business, delivering practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.

Since its foundation in 1907, Imperial's contributions to society have included the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of research for the benefit of all continues today, with current focuses including interdisciplinary collaborations to improve global health, tackle climate change, develop sustainable sources of energy and address security challenges.

In 2007, Imperial College London and Imperial College Healthcare NHS Trust formed the UK's first Academic Health Science Centre. This unique partnership aims to improve the quality of life of patients and populations by taking new discoveries and translating them into new therapies as quickly as possible.

Website: http://www.imperial.ac.uk

3. The Medical Research Council

Over the past century, the Medical Research Council has been at the forefront of scientific discovery to improve human health. Founded in 1913 to tackle tuberculosis, the MRC now invests taxpayers' money in some of the best medical research in the world across every area of health. Twenty-nine MRC-funded researchers have won Nobel prizes in a wide range of disciplines, and MRC scientists have been behind such diverse discoveries as vitamins, the structure of DNA and the link between smoking and cancer, as well as achievements such as pioneering the use of randomised controlled trials, the invention of MRI scanning, and the development of a group of antibodies used in the making of some of the most successful drugs ever developed. Today, MRC-funded scientists tackle some of the greatest health problems facing humanity in the 21st century, from the rising tide of chronic diseases associated with ageing to the threats posed by rapidly mutating micro-organisms. http://www.mrc.ac.uk

The MRC Centenary Timeline chronicles 100 years of life-changing discoveries and shows how our research has had a lasting influence on healthcare and wellbeing in the UK and globally, right up to the present day. http://www.centenary.mrc.ac.uk


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