Reuters- Kate Kelland

Health data released on Wednesday provided the clearest evidence to date of the spread of chronic diseases like diabetes and heart disease from developed nations to poorer regions such as Africa, as lifestyles and diets there change.

The United Nations data showed one in three adults worldwide has raised blood pressure - the cause of around half of all deaths from stroke and heart disease - and the condition affects almost half the adult population in some countries in Africa.

In its annual report on global health, the Geneva-based World Health Organisation (WHO) also said one in 10 adults worldwide has diabetes, an illness that costs billions of dollars to treat and puts sufferers at risk of heart disease, kidney failure and blindness.

While the average global prevalence of diabetes is around 10 percent, the report said, up to a third of the population in some Pacific Island countries have the condition.

Chronic diseases like diabetes, heart disease and cancer are often thought of as illnesses which primarily affect people in wealthy nations, where high fat diets, alcohol consumption and smoking are major health risks.

But the WHO says almost 80 percent of deaths from such diseases now occur in low- and middle-income countries.

In Africa, rising smoking rates, a shift towards Western- style diets and less exercise mean chronic or so-called non-communicable diseases are rising rapidly and are expected to surpass other diseases as the most common killers by 2020.

"This report is further evidence of the dramatic increase in the conditions that trigger heart disease and other chronic illnesses, particularly in low- and middle-income countries," the WHO's director general Margaret Chan said in a statement with the report.

"In some African countries, as much as half the adult population has high blood pressure."

This year's WHO statistical report was the first to include data from all 194 member countries on the percentage of men and women with high blood pressure, or hypertension, and with raised blood sugar levels, a symptom of diabetes.

This report does not examine the causes behind the rising or falling numbers, but seeks to give a snapshot of major diseases and health risks affecting the global population.

In wealthy countries, widespread diagnosis and treatment with low-cost drugs have significantly reduced average blood pressure readings across populations - and this has contributed to a reduction in deaths from heart disease, the WHO said.

But in Africa, more than 40 percent -- and in some places up to 50 percent - of adults in many countries are estimated to have high blood pressure.

Most of these people remain undiagnosed, the report said, and yet many could be treated with inexpensive medicines - an intervention that would cut the risk of death and disability from heart disease and stroke.

Obesity is another major issue, the WHO said, with data showing rates of obesity doubling in every region of the world between 1980 and 2008.

"Today, half a billion people - or 12 percent of the world's population - are considered obese," said Ties Boerma, the WHO's director of health Statistics and information systems.

The highest obesity levels are in the Americas, where 26 percent of adults are obese, and the lowest are in south east Asia, at 3 percent of adults.

The report found that women in all parts of the world are more likely to be obese than men, and are therefore at greater risk of diabetes, heart disease and some cancers.

The WHO's World Health Statistics report is published annually and contains data from 194 countries on a range of health indicators including life expectancy, illnesses and deaths from various diseases, health services, treatments, and risk factors or behaviors that affect health.

World Health Statistics 2012 is available at: here .

Other key trends identified in the report include:

* Maternal deaths:

- In 20 years, the number of maternal deaths has dropped from more than 540,000 in 1990 to less than 290,000 in 2010 - a decline of 47 percent. A third of these deaths were in just two countries - India with 20 percent of the global total, and Nigeria with 14 percent.

* Child deaths:

- Data from 2000 to 2010 show the world has made significant progress in reducing child deaths, cutting them from almost 10 million under-fives in 2000 to 7.6 million in 2010. Falls in numbers of deaths from diarrheal disease and measles have been particularly striking, the WHO said.

* Death registration:

- Only 34 countries - representing 15 percent of the world's population - produce high-quality cause-of-death data. In low and middle-income countries, fewer than 10 percent of deaths are registered.

(Editing by Andrew Roche)

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