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Growth of obesity in poor countries alarming: researchers

The weight of the world is growing evermore: New research shows that the worldwide prevalence of obesity has doubled since 1980.

Globally, almost 1.5 billion adults are overweight - one in three. That figure includes the 297 million women and 205 million men who are obese - one in nine adults.

In high-income countries like Canada and the U.S., being overweight is now the norm, with mean body mass index ringing in at 26.6. (BMI is an approximation of body fat based on height and weight. A BMI above 25 signifies being overweight and over 30, obese.)

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In middle-income countries like Chile and Ukraine, where the mean BMI is 26.1, being fat is also the new normal. Even low-income countries like Haiti and Zimbabwe are seeing their citizens pack on the pounds, with a mean BMI of 22.3.

"This tsunami of obesity will eventually affect all regions of the world," said Salim Yusuf, head of the Population Health Research Institute at McMaster University in Hamilton, Ont.

The research, contained in a series of articles published in Friday's edition of The Lancet, also looked at rates of high blood pressure and cholesterol. The studies examined trends in 199 countries between 1980 and 2008.

More than one billion people on the planet now have uncontrolled hypertension - meaning their blood pressure exceeds 140/90 millimetres of mercury.

Hypertension is the single biggest risk factor for heart attacks and strokes.

(Blood pressure is determined using a sphygmomanometer, an instrument that measures the force of the blood against the blood vessel walls. It is expressed in two numbers: Systolic pressure, the upper number, is the pressure when the heart contracts; diastolic pressure, the lower number, is the pressure when the heart is relaxed. Healthy adults should have a blood pressure in the range of 120/80 mmHg, although that target varies with age and other health conditions.)

The surprise in the new research is that rates of hypertension are actually falling despite the increase in obesity.

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But Majid Ezzati, chairman of global environmental health at Imperial College in London and lead author of the study, cautioned that the drops are pronounced in wealthy countries, where use of blood pressure medications are commonplace, and modest or non-existent in poorer countries.

The push to reduce salt in foods is likely also playing a role, as are falling smoking rates, he said.

The research shows that rates of serum cholesterol changed very little between 1980 and 2008, again despite the marked increase in the number of overweight and obese citizens.

Globally, the mean rate is 4.64 millimoles per litre total cholesterol for men and 4.76 mmol/L for women. (The desirable rate is below 5 mmol/L.) But, again, Dr. Ezzati said that the overall cholesterol number masks important regional differences.

In high-income countries like Canada and Japan, cholesterol rates are highest, but falling, again because of ready access to medication. In middle- and low-income countries, cholesterol numbers are on the rise.

Dr. Yusuf said the large increase in people who are overweight and obese is troubling but the data suggest that some of the health problems that are expected to follow - notably heart disease - can be mitigated.

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In fact, in high-income countries, where obesity rates are highest, death rates from cardiovascular disease are falling.

The research "suggests that directly controlling blood pressure, total cholesterol and smoking will lead to rapid and substantial reductions in cardiovascular disease rates even while obesity and diabetes might be increasing," Dr. Yusuf said.

He said implementing prevention and treatment strategies - including low-cost blood pressure and cholesterol medications, reducing salt intake and smoking - can have a dramatic impact, one that will be bolstered if measures are taken to stem the increase in obesity.

Conversely, he said, doing nothing will result in tens of millions of preventable deaths from cardiovascular disease in low- and middle-income countries in coming years.

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About the Author
Public health reporter

André Picard is a health reporter and columnist at The Globe and Mail, where he has been a staff writer since 1987. He is also the author of three bestselling books.André has received much acclaim for his writing. More

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