Updated

Having multiple generations living under one roof may take a toll on women's heart health, a large study of Japanese adults suggests.

The study, which started following nearly 91,000 middle-aged and older adults in 1990, found that women who lived with their spouse, children and parents or parents-in-law were at elevated risk of developing heart disease.

Compared with their counterparts who lived with a husband only, these women were about three times more likely to be diagnosed with coronary heart disease by 2004.

Furthermore, women who lived with their spouse and children had twice the risk of heart disease as women who shared their home with a spouse alone.

In contrast, there was no evidence that living with multiple family generations affected men's heart health, the researchers report in the medical journal Heart.

It's possible, or even likely, that chronic stress explains why such living arrangements would affect women in particular, according to the research team, led by Dr. A. Ikeda of Osaka University in Japan.

Even with other factors considered — like age, exercise habits and smoking — living arrangements were still linked to the risk of heart disease in women. In fact, women living with multiple generations had a low rate of smoking and tended to drink less than other women.

All of this, Ikeda's team writes, suggests that the stress of having multiple roles in the household — wife, mother and daughter or daughter-in-law — may exact a toll on some women's cardiovascular health.

Over time, the researchers note, chronic stress affects the nervous system, which can, for instance, exacerbate high blood pressure, hinder the normal functioning of the blood vessels or contribute to the formation of blood clots.