A Chinese research team surveyed more than 5,000 couples living in seven regions of China and found that people whose spouse had heart disease were more than twice as likely to develop it as well.

The association was particularly strong for men; the study found 28 percent of men whose wives had heart disease also had heart problems, compared to 12.8 percent of men whose wives didn’t have heart disease. This association was highest for men whose wives had a history of stroke and obesity, and were smokers.

Heart disease risk was 21 percent for women with spouses who had heart disease, compared to just 9 percent for those with healthy husbands. For women, heart disease was highest among those whose husbands had a history of stroke, according to the study presented at the American College of Cardiology.

It’s no mystery why couples are at higher risk of both partners developing heart disease. When you’re part of a couple, you share the same home environment. This can mean that couples influence each other when it comes to what they eat and whether they tend to live active or sedentary lifestyles.

Smoking can be another big factor. One partner who smokes may influence the other to pick up the habit. But even if they don’t, it exposes the nonsmoking partner to secondhand smoke, which can lead to cancer and/or cardiovascular disease.