National, regional, and global trends in systolic blood pressure since 1980: systematic analysis of health examination surveys and epidemiological studies with 786 country-years and 5.4 million participants

Abstract

New research shows that global systolic blood pressure (SBP) has decreased slightly since 1980, but trends varied significantly across regions and countries. However, because of population growth and aging, the number of people with uncontrolled hypertension increased from 605 million in 1980 to 978 million in 2008. The study, National, regional, and global trends in systolic blood pressure since 1980: systematic analysis of health examination surveys and epidemiological studies with 786 country-years and 5.4 million participants, authored by Dr. Majid Ezzati, Affiliate Associate Professor at IHME, Dr. Stephen Lim, Associate Professor of Global Health at IHME, and collaborators, examined 5.4 million participants in one of the first worldwide analyses of trends in blood pressure. Researchers developed a novel method to estimate mean SBP by age, country, and year.

Research findings

Women in Australasia had the lowest worldwide age-standardized SBP in 2008 (117.6 mm Hg); men in North America had the lowest SBP in 2008 (123.3 mm Hg). By country, South Korea, Cambodia, Australia, Canada, and the United States showed the lowest SBP estimates for both men and women in 2008.

Over the time period studied, mean body mass index (BMI), a measure of body fatness, increased in most regions of the world. The authors suggest the blood pressure decreases in high-income countries may have been more impressive had BMI remained at 1980 levels.

Analytical approach

Researchers estimated trends and their uncertainties in SBP for adults 25 years and older in 199 countries and territories for 1980 to 2008, using data from published and unpublished health examination surveys and epidemiological studies. Because many country-years were without data, yearly risk factor data are available for very few countries, and existing studies do not cover every age, sex, or geographic population group, the researchers developed a new statistical model to estimate mean SBP over time by age group, sex, and country.

Research objective

Because high blood pressure is the leading risk factor for cardiovascular disease mortality and causes more than 7 million deaths annually worldwide, accurately measuring population blood pressure is a critical public health problem. Policymakers need reliable data for trends in blood pressure to set intervention priorities, allocate scarce resources, and evaluate national programs.

Much of the existing research is based on cohort and community studies, mainly from high-income countries. The study authors wanted to systematically assess worldwide trends in blood pressure, account for sources of uncertainty in the data, and address missing data.

This study was part of the Global Burden of Diseases, Injuries, and Risk Factors Study, which examines critical questions essential to understanding the current state of population health worldwide.  In collaboration with 800 researchers, IHME is producing estimates in 21 regions around the world of disease burden by age and sex over two decades to measure the impact of approximately 300 health conditions and 40 health risk factors.

Recommendations for future work

The health benefits of low blood pressure have been established in previous studies, but future research should examine the mortality effects of the estimated trends in SBP seen in this study. The researchers also note that research should investigate the behavioral, environmental, nutritional, and health systems factors that may influence SBP to increase or decrease in a region over time. These data could inform programs and policies to accelerate the falling trends seen in SBP in this study.