More than one in ten of us around the world is now obese, nearly double the figure of thirty years ago, according to a major analysis of global risk factors that also reports high-income nations have achieved impressive reductions in blood pressure and cholesterol, with some doing much better than others.
The analysis, published as three papers in The Lancet today, shows country by country trends from 1980 to 2008 in three important heart disease risk factors: obesity, cholesterol, and blood pressure; and comes from the Global Burden of Diseases, Injuries and Risk Factors Study, which is funded by the Bill and Melinda Gates Foundation and the World Health Organization (WHO).
An international team of researchers, led by Professor Majid Ezzati from Imperial College London in the UK and Dr Goodarz Danaei from the Harvard School of Public Health in the US, reviewed the available global data to assess how body mass index (BMI), blood pressure and cholesterol changed between 1980 and 2008.
The World Health Organization and a number of other institutions also collaborated on the work.
Ezzati told the press:
“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,” he suggested.
The BMI analysis shows that in 2008, more than one in ten of the adults in the world was obese, with women more likely to be so than men. The researchers estimate 205 million men and 297 million women, that is more than half a billion adults worldwide, were obese in 2008.
The analysis on blood pressure shows that between 1980 and 2008, there was a modest fall in the proportion of the world’s population with uncontrolled hypertension or high blood pressure, but because the world’s population is aging and growing, the number of people with this condition went up from 600 to nearly 1 billion over the three decades.
High-income countries achieved large drops in population proportions with high blood pressure, the steepest being in Australasian women and North American men, said the researchers, who defined hypertension as having a systolic pressure higher than 140 mmHg or a diastolic pressure higher than 90 mmHg.
The cholesterol analysis shows that over the same period, the average levels of total blood cholesterol fell in high-income nations in North America, Australasia and Europe but went up in East and Southeast Asia and the Pacific region.
Ezzati said these figures show that overweight and obesity, high blood pressure and high cholesterol are no longer just Western problems or problems of wealthy nations.
“Their presence has shifted towards low and middle income countries, making them global problems,” he said.
He and his colleagues also looked within these global patterns at how countries compare in terms of each of the three risk factors: BMI, blood pressure, cholesterol. The highlights include:
Body Mass Index (the ratio of a person’s weight to their height squared, measured in kg per meter squared, kg/m2) is a measure of obesity, which is defined as having a BMI over 30 kg/m2).
- The proportion of adult women in the world classed as obese rose from 7.9% to 13.8% between 1980 and 2008.
- For men this figure went from 4.8% to 9.8%.
- Over the period, BMI went up by 0.4 kg/m2 per decade for men and 0.5 kg/m2 for women, the fastest rise being in the US (more than 1 kg/m2 per decade), followed by New Zealand and Australia for women and followed by UK and Australia for men.
- In some Western European countries there was hardly any rise in BMI for women.
- The region with the highest average BMI in the world is the Pacific Island nations with 70 per cent more people with BMI in the range 34-35 kg/m2 than some Southeast Asian and sub-Saharan African countries.
- Average BMI was lowest in Bangladesh (20·5 kg/m2) for women and lowest in Democratic Republic of the Congo (19·9 kg/m2) for men.
- Among high-income nations, the US has the highest average BMI (over 28 kg/m2 for men and women), followed by New Zealand, with Japan having the lowest (about 22 kg/m2 for women and 24 for men), followed by Singapore.
- The UK has the sixth highest BMI in Europe for women and ninth highest for men (both about 27 kg/m2).
- In Europe, the countries with the highest BMI are Turkey for women and the Czech Republic for men (both about 28 kg/m2).
- Swiss women appear to have the lowest BMI in Europe (about 24 kg/m2).
- In most regions of the world, men have higher blood pressure than women.
- Average systolic blood pressure is highest in Baltic and East and West African nations, up to 135 mmHg for women and 138 for men.
- These levels are on a par with those of Western European nations in the 1980s, before they started to come down rapidly.
- Nations with some of the lowest average blood pressure in both the female and male adult population include South Korea, Cambodia, Australia, Canada and the US (below 120 mmHg for women and 125 for men).
- Portugal, Finland and Norway have the highest average blood pressure among high income nations.
- Although total cholesterol fell in the high-income region consisting of Australasia, North America, and western Europe, and in central and eastern Europe, 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.
- The lowest average cholesterol levels are in sub-Saharan Africa at 4·08 mmol/L for men and 4·27 mmol/L for women.
- Greece has the lowest cholesterol for both men and women in the high income countries (under 5 mmol/L), and the US,
Ezzati said that:
“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.”
He said the High-level Meeting of the United Nations General Assembly on Non-Communicable Diseases in September 2011 should pay special attention to ways to address cardiovascular risk with improved policies and targets.
Danaei said this was the first time that anyone has tried to estimate the trends in these risk factors at the global and country by country level:
“The amount of data we collected is unprecedented and vast, and allows us to draw robust conclusions,” he stressed.
Dr. Gretchen Stevens, from the World Health Organization, who was also involved in the research said:
“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,” she urged.
“National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9.1 million participants.”
Mariel M Finucane, Gretchen A Stevens, Melanie J Cowan, Goodarz Danaei, John K Lin, Christopher J Paciorek, Gitanjali M Singh, Hialy R Gutierrez, Yuan Lu, Adil N Bahalim, Farshad Farzadfar, Leanne M Riley, Majid Ezzati,on behalf of the Global Burden of Metabolic Risk Factors of Chronic Diseases Collaborating Group (Body Mass Index).
“National, regional, and global trends in serum total cholesterol since 1980: systematic analysis of health examination surveys and epidemiological studies with 321 country-years and 3.0 million participants.”
Farshad Farzadfar, Mariel M Finucane, Goodarz Danaei, Pamela M Pelizzari , Melanie J Cowan, Christopher J Paciorek, Gitanjali M Singh, John K Lin, Gretchen A Stevens, Leanne M Riley, Majid Ezzati, on behalf of the Global Burden of Metabolic Risk Factors of Chronic Diseases Collaborating Group (Cholesterol).
“National, regional, and global trends in systolic blood pressure since 1980: systematic analysis of health examination surveys and epidemiological studies with 786 country-years and 5.4 million participants.”
Goodarz Danaei, Mariel M Finucane, John K Lin, Gitanjali M Singh, Christopher J Paciorek, Melanie J Cowan, Farshad Farzadfar, Gretchen A Stevens, Stephen S Lim, Leanne M Riley, Majid Ezzati, on behalf of the Global Burden of Metabolic Risk Factors of Chronic Diseases Collaborating Group (Blood Pressure).
Additional source: Imperial College London (3 Feb 2011 press release).
Written by: Catharine Paddock, PhD