Three papers published Online First by The Lancet show that the worldwide prevalence of obesity has nearly doubled since 1980. Meanwhile high-income countries have shown impressive reductions in mean blood pressure and cholesterol levels, with some countries doing much better than others. The Articles show that every region and country has its own story to tell. The papers were written by Prof Majid Ezzati, Imperial College London, UK; Dr Goodarz Danaei, Harvard School of Public Health, Boston, MA, USA, and colleagues.
The study shows that in 2008, more than one in ten of the world's adult population was obese, with women more likely to be obese (BMI above 30 kg/m2) than men. An estimated 205 million men and 297 million adult women were obese – a total of more than half a billion adults worldwide.
The percentage of the world's population with uncontrolled hypertension (high blood pressure), fell modestly between 1980 and 2008. However, because of population growth and ageing, the actual number of people with uncontrolled hypertension rose from 600 million in 1980 to nearly 1 billion in 2008. High-income countries achieved large reductions in uncontrolled hypertension, with the most impressive progress seen in women in Australasia and men in North America. Uncontrolled hypertension is defined as a systolic blood pressure higher than 140 mmHg or diastolic blood pressure higher than 90 mmHg.
Average levels of total blood cholesterol fell in Western countries of North America, Australasia and Europe, but increased in East and Southeast Asia and the Pacific region.
Professor Majid Ezzati*, the senior author of the study from the School of Public Health at Imperial College London, said: "Our results show that overweight and obesity, high blood pressure and high cholesterol are no longer Western problems or problems of wealthy nations. Their presence has shifted towards low and middle income countries, making them global problems."
Beyond global trends, the studies reveal how different countries compare in terms of each risk factor. The results show that:
- In 2008, 9.8 per cent of men and 13.8 per cent of women in the world were obese (with a BMI above 30 kg/m2), compared with 4.8 per cent for men and 7.9 per cent for women in 1980.
- Pacific island nations have the highest average BMI in the world, reaching 34-35 kg/m2, up to 70 per cent higher than some countries in Southeast Asia and sub-Saharan Africa.
- Among high income countries, USA has the single highest BMI (over 28 kg/m2 for men and women), followed by New Zealand. Japan has the lowest BMI (about 22 kg/m2 for women and 24 kg/m2 for men), followed by Singapore.
- Among high-income countries, between 1980 and 2008, BMI rose most in USA (by more than 1 kg/m2/decade), followed by New Zealand and Australia for women and followed by UK and Australia for men. Women in a few Western European countries had virtually no rise in BMI (less than 1 kg/m2 across the whole 28 years) for example Belgium, Finland, France, Switzerland. Italy was the only high-income European country in which female BMI may have fallen from 1980 to 2008. Italy and Switzerland also saw one the smallest increases in male BMI across the whole study period.
- The UK has the sixth highest BMI in Europe for women and ninth highest for men (both around 27 kg/m2).
- Turkish women and Czech men have the highest BMI in Europe (both around 28 kg/m2). Swiss women had the lowest BMI in Europe (around 24 kg/m2), while French men had one of the lowest (just under 25 kg/m2)
- Excess bodyweight is an important risk factor for cardiovascular disease, musculoskeletal disorders, diabetes, and cancer, and is estimated to cause nearly 3 million deaths worldwide each year.
- Systolic blood pressure levels are highest in Baltic and East and West African countries, reaching 135 mmHg for women and 138 mmHg for men. These levels were seen in some Western European countries in the 1980s before their impressive declines.
- South Korea, Cambodia, Australia, Canada and USA had some of the lowest blood pressures for both men and women, below 120 mmHg for women and below 125 mmHg for men.
- Among high income countries, Portugal, Finland and Norway have the highest blood pressure.
- Blood pressure fell more for women than men in the UK; but for both sexes, blood pressure fell by less than in most other European high-income countries. Actual blood pressure levels in 2008 for both men and women in the UK were mid-ranking in Western Europe.
- Men had higher blood pressure than women in most world regions
- While more evidence is needed, the authors suggest that the main determinants of blood pressure trends are likely to be patterns of consumption of salt and fruits and vegetables, levels of overweight and obesity, and use of antihypertensive drugs. They also suggest that blood pressure falls in high-income countries might have been better had BMI in those countries remained at 1980 levels.
- High blood pressure is the leading risk factor for cardiovascular disease mortality and causes more than 7 million deaths worldwide annually
- Western European countries like Greenland, Iceland, Andorra, and Germany have the highest cholesterol levels in the world, with mean serum total cholesterols of around 5.5 mmol/L. African countries have the lowest cholesterol, some as low as 4 mmol/L.
- Among western high-income countries, Greece has the lowest cholesterol for both men and women (below 5 mmol/L). USA, Canada, and Sweden also had low cholesterol.
- The UK's cholesterol is ninth highest in the world, slightly below 5.5 mmol/L. However UK men and women have both shown one of the largest drops in cholesterol in all high-income countries, from 6.2 mmol/L to 5.4 mmol/L.
- Uniquely among high-income countries, Japan has seen its average cholesterol in men and women rise from a low starting point in 1980 to the levels seen in Western Europe in 2008. Singapore saw cholesterol drop from 1980 to 2000 then rise substantially. China also saw increases in cholesterol though its figures remain low in global terms. The patterns in Japan, China and Singapore are likely to be at least partly due to changes in diet, including increasing intake of animal products and fats.
Professor Ezzati says*: "It's heartening that many countries have successfully reduced blood pressure and cholesterol despite rising BMI. Improved screening and treatment probably helped to lower these risk factors in high-income countries, as did using less salt and healthier, unsaturated fats.
"The findings are an opportunity to implement policies that lead to healthier diets, especially lower salt intake, at all levels of economic development, as well as looking at how we improve detection and control through the primary healthcare system. Policies and targets for cardiovascular risk factors should get special attention at the High-level Meeting of the United Nations General Assembly on Non-Communicable Diseases in September 2011."
Dr. Goodarz Danaei says*: "This is the first time that anyone has tried to estimate trends in these major risk factors in every country in the world. The amount of data we collected is unprecedented and vast, and allows us to draw robust conclusions."
Dr. Gretchen Stevens, WHO, Switzerland, adds*: "Our study helps track the obesity problem in individual countries and regions. We know that changes in diet and in physical activity have contributed to the worldwide rise in obesity, but it remains unclear which policies would effectively reduce obesity. We need to identify, implement, and rigorously evaluate policy interventions aimed at reversing the trends, or limiting their harmful effects."
In a linked Comment, Professor Salim Yusuf and Dr Sonia S Anand, Population Health Research Institute, McMaster University, Hamilton, ON, Canada, say that the contrasting patterns of obesity vs blood pressure and total cholesterol in these findings suggest that directly controlling blood pressure, total cholesterol, and smoking will lead to rapid and substantial reductions in cardiovascular disease rates even while obesity and (type 2) diabetes might be increasing.
They say: "Therefore focusing on controlling these three risk factors (blood pressure, total cholesterol, and smoking) will rapidly and to a large extent reduce cardiovascular disease globally within a few years, while we continue our efforts to stem and ultimately reverse the tide of obesity, which will need more prolonged and societal-based interventions over decades."
To contact Prof Ezzati, please contact Colin Smith, Media Officer, Imperial College London. T) +44(0)20 7594 6712 / (Out of hours) +44(0)7803 886 248 E) email@example.com /firstname.lastname@example.org
Professor Salim Yusuf and Dr Sonia S Anand, Population Health Research Institute, McMaster University, Hamilton, ON, Canada. T) +1 905 297 3781 E) email@example.com
For full blood pressure paper see: http://press.thelancet.com/bp.pdf
For a chart showing country by country systolic blood pressure trends from 1980 to 2008, see: http://press.thelancet.com/countrybp.pdf
For full cholesterol paper see: http://press.thelancet.com/cholest.pdf
For a chart showing country by country systolic blood pressure trends from 1980 to 2008, see: http://press.thelancet.com/countrychol.pdf
Notes to editors: extra quote from Prof Ezzati: "Trends in the UK, USA, Canada and Australia have plenty of unexpected findings: These countries all have done poorly in terms of controlling overweight and obesity, with US having the worst performance of any wealthy nation. But American men have fared better than men in Australia, Canada, and the UK in lowering their blood pressure, and in fact better than most other wealthy countries. Among women, Australia clearly outperformed the other 3 in blood pressure control. When it comes to controlling cholesterol, the UK has had the largest reductions of these 4 countries but its cholesterol is still higher than the other 3 because it had very high levels in 1980."
The work forms part of the Global Burden of Diseases, Injuries and Risk Factors Study, which is supported by the Bill and Melinda Gates Foundation. The study also received funding from the World Health Organization (WHO).
*Quotes taken directly from authors, not found in text of Articles
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