Canada and the United States have the fewest patients, at less than 20 percent of adults, but in some African countries the estimated figure is closer to 50 percent, the World Health Organization said.

Increased life expectancy and changes in lifestyle mean that chronic conditions once associated with wealthier nations are now affecting lower income countries.

"We are being successful in reducing the impact of infectious diseases and child mortality is coming down -- that means more people are surviving to advanced ages when non-communicable diseases develop," said Colin Mathers, coordinator of the WHO s mortality and burden of disease unit.

"As people live longer, they are more prone to chronic diseases."

Mathers also pointed to increasing risk factors in lower-income countries such as obesity and smoking.

"As populations become better off, incomes are rising, and the calories available are increasing." he said.

"The spread of fast food, processed food, salt added in manufacturing, is all contributing to cardiovascular and cancer risks."
In many developed countries like Australia, where the incidence of heart problems peaked in the 1960s and 70s, people are diagnosed and given treatment.

But those treatments are not generally available in African countries, said Mathers.

In Niger 50.3 percent of men suffer from high blood pressure, with Malawi and Mozambique not far behind at 44.5 and 46.3 percent respectively.

The WHO World Health Statistics report published on Tuesday includes for the first time figures on raised blood pressure and raised blood glucose levels, associated with diabetes, for the first time.