Worldwide Trends in Blood Pressure From 1975 to 2015

Study Questions:

Has there been a change in worldwide trends for mean systolic and mean diastolic blood pressure (BP), and the prevalence of, and number of people with, raised BP, defined as systolic BP (sBP) of ≥140 mm Hg or diastolic BP (dBP) of ≥90 mm Hg?

Methods:

The authors pooled national, subnational, or community population-based studies that had measured blood pressure in adults aged ≥18 years. A Bayesian hierarchical model was used to estimate trends from 1975 to 2015 in mean sBP and mean dBP, and the prevalence of raised BP for 200 countries. They calculated the contributions of changes in prevalence versus population growth and aging to the increase in the number of adults with raised BP.

Results:

The 1,479 studies had measured the BPs of 19.1 million adults. Global age-standardized mean sBP in 2015 was 127.0 mm Hg in men and 122.3 mm Hg in women; age-standardized mean dBP was 78.7 mm Hg for men and 76.7 mm Hg for women (95% confidence interval [CI] was about 2 mm Hg for each). Global age-standardized prevalence of raised BP was 24.1% (95% CI, 21.4–27.1) in men and 20.1% (95% CI, 17.8–22.5) in women in 2015. Mean sBP and dBP decreased substantially from 1975 to 2015 in high-income western and Asia Pacific countries, moving these countries from having some of the highest worldwide BPs in 1975 to the lowest in 2015. Mean BP also decreased in women in central and eastern Europe, Latin America, and the Caribbean, and, more recently, central Asia, Middle East, and north Africa. The estimated trends in these super-regions had larger uncertainty than in high-income super-regions. By contrast, mean BP might have increased in other areas in Asia, Oceania, and sub-Saharan Africa. In 2015, central and eastern Europe, sub-Saharan Africa, and south Asia had the highest BP levels. Prevalence of raised BP decreased in high-income and some middle-income countries; it remained unchanged elsewhere. The number of adults with raised BP increased from 594 million in 1975 to 1.13 billion in 2015, with the increase largely in low-income and middle-income countries. The global increase in the number of adults with raised BP is a net effect of increase due to population growth and ageing, and decrease due to declining age-specific prevalence, particularly in the high-income western super-region.

Conclusions:

During the past four decades, the highest worldwide BP levels have shifted from high-income countries to low-income countries in south Asia and sub-Saharan Africa due to opposite trends, while blood pressure has been persistently high in central and eastern Europe.

Perspective:

This is an important study demonstrating that BP and hypertension are very much dependent on socioeconomic status and can improve but also worsen in developing countries. While the trends have validity, the actual pressures and inter-population variability may not because techniques and equipment used in the different countries varied, particularly over the 40 years (e.g., quality of the cuff, multiple or single cuff sizes, and automated digital device vs. standard mercury sphygmomanometer). Among the many other important variables include time of day, activity within the few hours prior to BP measure, resting for 5 minutes, back support, and one versus multiple sampling. The sum variability for each could be as much as a 10-15 systolic and 5-7 diastolic sampling error compared to optimal techniques with morning home BP measurements.

Clinical Topics: Diabetes and Cardiometabolic Disease, Heart Failure and Cardiomyopathies, Prevention, Hypertension

Keywords: Aging, Africa South of the Sahara, Asia, Blood Pressure, Diastole, Europe, Eastern, Hypertension, Metabolic Syndrome X, Poverty, Population Growth, Primary Prevention, Social Class, Socioeconomic Factors, Systole


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