According to a recent meta-study, there were at least 1.1 billion adults around the world suffering from hypertension as of 2015, compared to only 594 million back in 1975.

The countries with the largest numbers of cases are mainly located in South Asia and Africa, while blood pressure levels in developed countries such as the U.K. and the U.S. are at an all-time low. The study pooled other research efforts where the blood pressure of adults older than 18 was noted and set into trends for average systolic and diastolic pressure and reviewed data from people of at least 200 countries. Researchers also took into consideration population growth, which could ostensibly increase the number of adults suffering from hypertension.

“About 70 million American adults (29%) have high blood pressure,” says the U.S. Centers for Disease Control and Prevention. Image credit:

A global picture of hypertension

By analyzing 1479 previous studies, researchers from the Non-Communicable Disease Risk Factor Collaboration (NCD-RisC) collected blood pressure data from 19.1 million adults. They obtained a global median of 127 mm Hg for systolic blood pressure in men and 1223.3 mm Hg for women. Diastolic blood pressure was 78.7 and 76.7 mm Hg for men and women, respectively.

When measuring blood pressure, the top number is systolic pressure, which accounts for the amount of pressure in the arteries that occurs when the heart contracts. The lower number is the diastolic pressure, which occurs when the heart rests between each beat.

The countries showing the most significant changes over the analyzed period were those labeled as “high-income” western and Asian-Pacific countries, which switched from having the highest blood pressure rates back in 1975 to having the lowest rates in 2015.

Women in central and eastern Europe and America also showed a lower mean diastolic and systolic blood pressure, while overall blood pressure seemed to increase in adults living in middle to low-income countries.

Poorer countries are at a higher risk

The NCD-RisC assures that high blood pressure is the main factor contributing to cardiovascular and chronic kidney disease, which is why the organization set a goal to lower the prevalence of raised blood pressure. This would translate to a systolic blood pressure higher than 140 mm Hg or a diastolic blood pressure higher than 90 mm Hg.

“This study provides the most complete picture of trends in adult blood pressure for all countries in the world with the longest observation period of any global blood pressure study to our knowledge, and includes trends in mean diastolic blood pressure and prevalence of raised blood pressure, which were not included in previous studies and are of clinical, public health, and health systems significance,” wrote the authors of the study.

The NCD-RisC recognized that it seems unlikely that a reduction in hypertension prevalence of 25 percent by 2025 will be achieved in south Asian, sub-Saharan and eastern European countries.

According to lead author Dr. Majid Ezzati, from the School of Public Health of the Imperial College in London, hypertension is the main cause of stroke and heart disease, killing over 7.5 million people each year. Most of these deaths occur in middle to low-income countries. He assured that high blood pressure ceased to be a problem of the developed world and now it weighs upon the world’s poorest nations.

Source: The Lancet