Middle-aged and older women who lacked social ties were much more likely than men to suffer from hypertension and stroke, warn researchers.

In a study, published in the Journal of Hypertension, the research team discovered that social isolation affects the health of men and women in different ways -- including placing women at higher risk of high blood pressure. "Among older adults, social isolation is the largest known risk factor for mortality, equal only to smoking," said study author Annalijn Conklin from the University of British Columbia in Canada. "Our research indicates that women, in particular, are more likely to be hypertensive when they experience isolation in middle and older age," Conklin added.

For the findings, the research team analysed the social ties of 28,238 adults aged 45 to 85. They found that women who were non-partnered, engaged in fewer than three social activities a month, or had a small social network (fewer than 85 contacts) had higher odds of hypertension. Average systolic blood pressure was highest among widowed, lone-living and socially inactive women, and the largest difference in blood pressure was between widowed and married women. Widowed women were found to have the strongest likelihood of hypertension across all categories.

Among men, the picture was quite different. Those who were single, shared a home with others, and had the largest social networks had the highest blood pressure, while those who had smaller networks and lived alone had lower blood pressure. The researchers found that combinations of different social ties also mattered. Regular social participation appeared to have a protective effect among non-partnered women, suggesting that health care providers may want to screen for the number of monthly social activities, and include these alongside healthy diet and exercise when treating non-partnered older women.

"Among women, the increase in blood pressure that was associated with the lack of social ties was similar to that seen with non-steroidal anti-inflammatory use, increased sodium diets pollution or weight gain," said Conklin. "This represents a significant women-specific risk factor for heart disease or stroke," Conklin added.