After analyzing more than two decades worth of data, researchers have found that high blood pressure and obesity, so-called "diseases of affluence," are no longer confined to countries with higher incomes.

Researchers at Imperial College London, Harvard School of Public Health and others studied data from 199 countries between 1980 and 2008 on the prevalence of risk factors related to heart and circulatory disease.

In 1980 there was a correlation between a country's income and the country's population's average blood pressure, cholesterol and body mass index (BMI).

By 2008 there was no correlation between national income and blood pressure levels in men, and in women blood pressure was higher in poorer countries.

The poorest countries still had populations with the lowest BMI levels, but BMI was found to be higher in middle-income countries than high-income countries.

Cholesterol remained higher in wealthy Western countries, the study found.

"This study shows that non-communicable diseases are no longer 'diseases of affluence'. They've shifted from being epidemic in rich countries to become a truly international pandemic, said research leader Professor Majid Ezzati, from the School of Public Health at Imperial College London, according to a statement.

"If current trends continue, developing countries will be confronted with a rising tide of obesity, diabetes and high blood pressure. Meanwhile, developed countries will continue to face an epidemic of diabetes and high cholesterol."

In the abstract, the study concluded that the changes associated with metabolic risk factors and macroeconomic variables indicate "there will be a global pandemic of hyperglycemia and diabetes mellitus, together with high blood pressure in low-income countries, unless effective lifestyle and pharmacological interventions are implemented."

The study's press statement and abstract did not mention any specific countries by name, though the World Bank provides up-to-date lists of what are considered the low-income, middle-income and high-income countries of the world. 

The new study's findings are consistent with a 2005 study which concluded that cardiovascular disease risks are expected to systematically shift to low-income and middle-income.

Results for the recent study are published in Circulation.