London: India recorded 200 million people with high blood pressure — a key risk factor for heart attack — in 2015 while China reported 226 million, says a study.

Globally, the number of people with high blood pressure has almost doubled in 40 years to 1.13 billion in 2015, with the majority of them in low and middle-income countries.

The study, published in the journal The Lancet, analysed changes in blood pressure from nearly 20 million persons in every country in the world between 1975 and 2015.

“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,” said lead author Majid Ezzati, Professor at the Imperial College London.

The findings showed that in 2015, 258 million (23 per cent) of the 1.13 billion adults with high blood pressure lived in South Asia (200 million in India) and another 235 million (21 per cent) lived in East Asia (226 million in China).

Britain was found to be the European country with the lowest proportion of people with high blood pressure in 2015, while South Korea, the US and Canada were lowest in the world.

While blood pressure has dropped sharply in high-income countries, it has risen in many low and middle-income countries, especially those in Africa and South Asia, the study observed.

“High blood pressure is no longer related to affluence — as it was in 1975 — but is now a major health issue linked with poverty,” said Ezzati.

Poor nutrition in early life years which raises the risk of the high blood pressure in later life, may explain the growing problem in poor countries, Ezzati added.

Further, men (597 million) had higher blood pressure than women (529 million) in most countries in the world in 2015.

Tackling the epidemic of high blood pressure in low and middle-income countries is one of the most pressing global health challenges, the researchers noted.

Effective policies that allow the poorest countries and people to have healthier diets — particularly reducing salt intake and making fruit and vegetables affordable — as well as improving detection and treatment with blood pressure lowering drugs may help in substantially reducing blood pressure.