THURSDAY, May 1 (HealthDay News) -- Roughly 80 percent of high blood pressure-related deaths in the world occur in developing nations, a new study by New Zealand researchers shows.

Once regarded as a problem only in high-income countries, high blood pressure is now a global problem that affects both rich and poor nations, the researchers said.

The researchers calculated that 7.6 million premature deaths (about 13.5 percent of the worldwide total) and 92 million disability-adjusted life years (DALYS) -- 6 percent of the worldwide total -- among people over age 30 were caused by high blood pressure in 2001.

About 54 percent of strokes and 47 percent of heart disease cases were attributed to high blood pressure. About half of those cases occurred in people with hypertension (greater than 140 mm Hg systolic), while the remainder occurred in people with lesser degrees of high blood pressure.

In high-income countries, the proportion of premature deaths due to high blood pressure was 17.6 percent, compared to 12.9 percent in middle- and low-income nations. The proportion of DALYS due to high blood pressure in high-income nations was 9.3 percent, compared to 5.6 percent in middle- and low-income nations.

However, 80 percent of worldwide high blood pressure-related deaths occurred in middle- and low-income nations in eastern Europe and Asia, including China and India. More than one-third of all deaths in lower-income nations in Europe and central Asia were related to high blood pressure.

In high-income countries there were 1.39 million high blood pressure-related deaths; 418,000 stroke deaths; 668,000 heart disease deaths; 109,000 deaths due to hypertensive disease; and 197,000 deaths due to other cardiovascular diseases.

In low- and middle-income countries, there were 6.22 million high blood pressure-related deaths: 2.5 million stroke deaths; 2.68 million heart disease deaths; 598,000 hypertensive disease deaths; and 445,000 deaths due to other cardiovascular diseases.

"Most of the disease burden caused by high blood pressure is borne by low-income and middle-income countries, by people in middle age, and by people with lesser degrees of high blood pressure. Prevention and treatment strategies restricted to rich countries or individuals with hypertension will miss much blood pressure-related disease," wrote the University of Auckland researchers.

The study is published in this week's issue of The Lancet.

"Middle-income countries and low-income regions have a five times greater burden of disease than high-income regions, with access to less than 10 percent of the global treatment resource... This travesty cannot continue to be ignored by those most able to bring about change," Stephen MacMahon, of the George Institute for International Health at the University of Sydney in Australia, and his international colleagues, wrote in an accompanying editorial.

More information

The American Heart Association has more about high blood pressure.