1.13bn people at risk as high blood pressure rates soar in poorer countries
A record 1.13 billion people around the world are living with high blood pressure, with the condition no longer mainly confined to richer Western countries, research has shown.
But there was better news for the UK, which emerged as the European country with the lowest proportion of people with the condition.
Global prevalence of high blood pressure, also known as hypertension, has almost doubled since 1975, when an estimated 594 million people were affected, the study found.
High blood pressure, which is linked to heart attacks and strokes, used to be thought of as a problem of the developed world. Today, it is poorer countries that are most threatened by rising rates of the conditiion, say scientists.
Professor Majid Ezzati, who led the international study, said: "High blood pressure is the leading risk factor for stroke and heart disease, and kills around 7.5 million people worldwide every year. Most of these deaths are experienced in the developing world.
"Taken globally, high blood pressure is no longer a problem of the Western world or wealthy countries. It is a problem of the world's poorest countries and people."
The trend might be explained by poor nutrition in early life, which has been shown to increase the risk of high blood pressure among adults, said Professor Ezzati, from Imperial College London.
In contrast, high income countries had driven down rates of hypertension.
Britain was one of those leading the way in this respect, the findings published in The Lancet medical journal revealed.
Last year 18% of men and 12% of women in the UK had high blood pressure, respectively the sixth and seventh lowest rates in the world. Britain had the lowest proportion of both men and women with high blood pressure in Europe.
The figures show a dramatic improvement since 1975, when 38% of British men and 28% of women had high blood pressure.
A diagnosis of hypertension is based on either or both of the two blood pressure readings. The first reading, systolic, measures pressure in the blood vessels with each pump of the heart. The second, diastolic, reading measures the "resting" pressure between pumps.
High blood pressure is defined as a systolic reading higher than 140 millimetres of mercury (mmHg) and a diastolic reading higher than 90 mmHg. Ideally, blood pressure should not be higher than 120/80 mmHg.
Research has shown that the risk of death from ischaemic (caused by lack of blood supply) heart disease and stroke doubles with every 20 mmHg systolic or 10 mmHg diastolic rise from middle age onwards.
The new study, the biggest of its kind ever conducted, involved the World Health Organisation and hundreds of scientists around the world.
Data from the blood pressure measurements of nearly 20 million people were analysed.
The most striking findings were the soaring rates of hypertension in low and middle-income countries in southern Asia and sub-Saharan Africa, and the big reductions in developed countries.
High blood pressure remained a serious problem in some central and eastern European countries, such as Hungary, Slovenia and Lithuania.
Over the past 40 years, the world's highest average blood pressure levels had shifted from high-income Western and Asia-Pacific countries, such as Japan, to low and middle-income countries in sub-Saharan Africa, southern Asia and some Pacific island nations.
The study showed that the WHO's target of reducing global high blood pressure prevalence by a quarter by 2025 was unlikely to be achieved without more effective policies focused on the poorest parts of the world.
Suggested strategies included helping people to have healthier diets - especially by reducing salt intake and making fruit and vegetables more affordable - as well as improving the detection and treatment of hypertension.
Among the stand-out findings from the 2015 data:
:: More than half the global total of adults with high blood pressure - 590 million - lived in east, south-east and southern Asia. Of these, 199 million lived in India and 226 million in China
:: Levels of systolic blood pressure were lowest in South Korea and Canada. (About 118 mmHg for men and 111 mmHg for women)
:: Canada, the UK, Australia, the US, Peru, South Korea and Singapore had the lowest proportion of adults living with high blood pressure - no more than one in five men and one in eight women
:: The five countries with the highest proportion of men with high blood pressure (nearly two in five) were all in central and eastern Europe: Croatia, Latvia, Lithuania, Hungary, and Slovenia
:: Africa had the top five countries with the highest proportion of women with high blood pressure: Niger, Chad, Mali, Burkina Faso, and Somalia. Roughly a third of women in these countries suffered from hypertension
:: Throughout the world, men tended to have higher blood pressure than women.