High blood pressure and obesity are no longer confined to wealthy countries, a new study has found.
These health risks have traditionally been associated with affluence, and in 1980, they were more prevalent in countries with a higher income.
The new research, published in Circulation, shows that the average body mass index of the population is now just as high or higher in middle-income countries. For blood pressure, the situation has reversed among women, with a tendency for blood pressure to be higher in poorer countries.
Researchers at Imperial College London, Harvard School of Public Health, and worldwide collaborators studied data from 199 countries between 1980 and 2008 on the prevalence of risk factors related to heart and circulatory disease. In 1980, a country's income was correlated with the population's average blood pressure, cholesterol and body mass index (BMI).
By 2008, there was no relationship between national income and blood pressure in men, and in women blood pressure was higher in poorer countries. BMI was still lowest in the poorest countries, but higher in middle-income countries than the wealthiest countries. Cholesterol remained higher in higher-income Western countries.
Fasting blood sugar, which is linked to diabetes, was only weakly related with income and affluence, but correlated with obesity.
Professor Majid Ezzati, from the School of Public Health at Imperial College London, who led the research, said: "This study shows that non-communicable diseases are no longer 'diseases of affluence'. They've shifted from being epidemic in rich countries to become a truly international pandemic.
"If current trends continue, developing countries will be confronted with a rising tide of obesity, diabetes and high blood pressure. Meanwhile, developed countries will continue to face an epidemic of diabetes and high cholesterol."
The study also found that BMI has consistently been related to the proportion of the population living in cities, suggesting that urban lifestyles might be playing an important role in the obesity problem, now and in the past.
The researchers suggest that the change in relationship between national income and blood pressure might be caused by improved diagnosis and treatment of high blood pressure in wealthier countries, and perhaps changes in diet and lifestyle.
"Developed countries have succeeded in reducing blood pressure," said Dr. Goodarz Danaei, one of the lead authors of the study from Harvard School of Public Health. "We need to replicate that success in developing countries by improving primary health care services, lowering salt intake and making fresh fruit and vegetables more available.
"High cholesterol is still linked to national wealth, probably because of the relatively high cost of meat and other animal products. Lower income countries should encourage the use of unsaturated fats over saturated fats to avoid the problems that richer countries have.
"Heart and circulatory diseases impose a huge cost on healthcare systems in high and middle income countries. Redirecting some of these resources to prevention might lead to savings in the long run."
The research was funded by the Medical Research Council and the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre.
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Notes to editors
1. G Danaei et al. 'The Global Cardiovascular Risk Transition: Associations of Four Metabolic Risk Factors with Macroeconomic Variables in 1980 and 2008.' Circulation, 2013; 127: 1493-1502. doi: 10.1161/CIRCULATIONAHA.113.001470 http://circ.ahajournals.org/content/127/14/1493.abstract
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.
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Website: http://www.imperial.ac.uk
3. About 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
4. About the NIHR
The National Institute for Health Research provides the framework through which the research staff and research infrastructure of the NHS in England is positioned, maintained and managed as a national research facility. The NIHR provides the NHS with the support and infrastructure it needs to conduct first-class research funded by the Government and its partners alongside high quality patient care, education and training. Its aim is to support outstanding individuals (both leaders and collaborators), working in world-class facilities (both NHS and university), conducting leading edge research focused on the needs of patients. http://www.nihr.ac.uk
5. About NIHR Biomedical Research Centres
NIHR Biomedical Research Centres support research across a wide range of disease areas. These Centres are the most outstanding NHS/University research partnerships in the country; leaders in scientific translation and early adopters of new insights in technologies, techniques and treatments for improving health. To ensure they are able to succeed, the NIHR BRCs receive substantial levels of sustained funding. NIHR BRC funding supports the NHS infrastructure to create an environment where scientific endeavour can thrive, attracting the foremost talent and producing world-class outputs.
Journal
Circulation