The level of received school education matters most when it comes to reducing the risk of high blood pressure, a medical study suggested Tuesday, breaking the conventional notion that illnesses are closely tied to income.

According to South Korea's Yonhap news agency a research team led by Lee Hae-young of Seoul National University Hospital looked into health conditions of 7,089 people from 2001-2007 to find correlations between hypertension and the level of education and income.

The study discovered that the number of patients with high blood pressure was 72 per cent higher among people with only elementary school education than college graduates.

The number for middle school graduates was 56 per cent higher, and for high school graduates, 33 per cent higher.

The team said a correlation study for income level did not show meaningful differences. The education level had the biggest effect among other variables, including age, gender, history of diabetes, obesity and extent of physical exercise, it said.

Some 29 per cent of the world's population are expected to have high blood pressure in 2025. In South Korea, 13.5 per cent of deaths have been linked to high blood pressure.

"We see the study results as an indication that people with higher education are more informed about illnesses and are more alert," Lee said.

"Based on other studies that show people with high levels of education smoke and drink less, their healthier life habits probably affected our results," Lee added. -- Bernama