The rate of elevated systolic blood pressure (SBP) has increased substantially across the globe between 1990 and 2015, researchers report, warning that the situation has put more people at an increased heart attack and stroke risk including in India.

In 2015, an estimated 3.5 billion adults had systolic blood pressure of at least 110-115 mm Hg and 874 million adults had SBP of 140 mm Hg or higher, said Christopher JL Murray from the Institute for Health Metrics and Evaluation (IHME), University of Washington in Seattle.

Systolic is the top number and diastolic is the bottom number when it comes to measuring blood pressure.

Five countries accounted for more than half of global disability-adjusted life years (DALYs) associated with SBP of at least 110 to 115 mm Hg -- China, India, Russia, Indonesia and the US.

The new analysis, published in the Journal of the American Medical Association, was based on 8.7 million people from 154 countries across 844 studies.

The largest numbers of SBP-related deaths were caused by ischemic heart disease (4.9 million), hemorrhagic stroke (2 million), and ischemic stroke (1.5 million).

"These estimates are concerning given that in 2015, an estimated 3.5 billion individuals had an SBP level of at least 110 to 115 mm Hg," the authors write.

The global obesity epidemic may further increase SBP in some populations, the findings showed.

Systolic blood pressure of at least 110 to 115 mm Hg was associated with more than 10 million deaths and more than 212 million DALYs in 2015 - a 1.4-fold increase since 1990.

Compared with all other specific risks quantified in a 2015 study, SBP of at least 110 to 115 mm Hg was the leading global contributor to preventable death in 2015.

"Both the projected number and prevalence rate of SBP of at least 110 to 115 mm Hg are likely to continue to increase globally. These findings support increased efforts to control the burden of SBP of at least 110 to 115 mm Hg to reduce disease burden," the researchers noted.

The new study suggests blood pressure should be kept low with diet control, exercise and stress reduction.