If your partner has hypertension, you are likely to have it too, says researchers of a new study.

The research team, which examined middle-aged and older heterosexual couples across China, England, India and the U.S., observed concordance of hypertension, a situation when both partners have high blood pressure.

The study was conducted by researchers from the University of Michigan, Emory University and Columbia University. The findings were published in the Journal of the American Heart Association.

The prevalence of concordant hypertension within couples was 37.9% in the U.S., 47.1% in England, 20.8% in China, and 19.8% in India.

"Many people know that high blood pressure is common in middle-aged and older adults, yet we were surprised to find that among many older couples, both husband and wife had high blood pressure in the U.S., England, China, and India," said senior author Chihua Li, from the University of Michigan. "For instance, in the U.S., among more than 35% of couples who were aged 50 or older, both had high blood pressure."

Previous studies have examined the concordance of hypertension and other diseases in couples, but those were limited to a single country setting or based on small regional samples.

"Ours is the first study examining the union of high blood pressure within couples from both high- and middle-income countries. We wanted to find out if many married couples who often have the same interests, living environment, lifestyle habits, and health outcomes may also share high blood pressure," said study co-lead author Jithin Sam Varghese, from Emory University in Atlanta.

The researchers evaluated 3,989 couples in the U.S., 1,086 in England, 6,514 in China and 22,389 in India. After analyzing their blood pressures, the team found that the prevalence of high blood pressure in both spouses or partners was highest in England, followed by the U.S.

Although hypertension is more common in the U.S. and the U.K., the likelihood of a wife having blood pressure when married to a person with hypertension is more prevalent in China and India.

"Compared to wives married to husbands without high blood pressure, wives whose husbands had high blood pressure were 9% more likely to have high blood pressure in the U.S. and England, 19% more likely in India, and 26% more likely in China," the researchers wrote.

Researchers believe it could be due to cultural factors.

"One reason might be cultural. In China and India, there's a strong belief in sticking together as a family, so couples might influence each other's health more. In collectivist societies in China and India, couples are expected to depend and support each other, emotionally and instrumentally, so health may be more closely entwined," said study co-lead author Peiyi Lu, from Columbia University Mailman School of Public Health.

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