Study shows lonely people at greater risk of hypertension

University psychologists have found a 30-point difference in systolic blood pressure readings between older Americans who experience loneliness and those who are not lonely, showing that loneliness could increase the risk of death from stroke and heart disease.

According to the lead investigators of the study, John Cacioppo, the Tiffany & Margaret Blake Distinguished Service Professor in Psychology, and Louise Hawkley, Senior Research Scientist with the Center for Cognitive and Social Neuroscience, the result is equivalent to the difference between a normal blood pressure of 120 and a level of 150, which signifies Stage--1 hypertension.

The point differences resulted, even when other factors such as depressive symptoms or perceived stress were taken into account. The differences were smallest at age 50 and greatest among the oldest adults tested, those at retirement age.

Hawkley and Cacioppo are the authors of the paper, “Loneliness is a Unique Predictor of Age-Related Differences in Systolic Blood Pressure,” published in the journal Psychology and Aging. Other co-authors are Christopher Masi, Assistant Professor in Medicine, and Jarett Berry of the department of preventive medicine at Northwestern University.

The increase in blood pressure associated with loneliness is about the same magnitude as blood pressure reductions attained through weight loss and regular physical activity in people suffering from hypertension. “By these standards, improvements in a sense of social connectedness may have clinical benefits comparable to lifestyle modifications,” the authors wrote.

The team based their research on a study of 229 people aged 50 to 68. The randomly chosen group includes whites, African Americans and Latinos who are part of a long-term study on aging. Members of the group were asked a series of questions to determine if they perceived themselves as lonely. They were asked to rate their connections with others through a series of topics, such as “I have a lot in common with the people around me,” “My social relationships are superficial,” and “I can find companionship when I want it.”

The research team also examined data on weight, alcohol consumption, smoking, blood pressure medications and demographic characteristics. They found that people who rated high on being lonely had a significantly higher blood pressure than non-lonely people with similar profiles on the other measures.

The research also showed that loneliness augments the normal increases in blood pressure associated with aging.

The paper builds on Cacioppo’s earlier research that demonstrated that loneliness is related to increased peripheral vascular resistance among young people. Although both lonely and non-lonely people in that study experienced stress, subjects in both studies reacted to stress differently.

“Lonely people differ from non-lonely individuals in their tendency to perceive stressful circumstances as threatening rather than challenging, and to passively cope with stress by failing to solicit instrumental and emotional support and by withdrawing from stress rather than actively coping and attempting to problem solve,” Cacioppo said.

The study on young people showed that stress caused an increase in resistance to blood flow brought on by their response to stress. Greater resistance to blood flow in lonely people compared to non-lonely individuals could increase blood pressure over the lifetime of lonely people, Cacioppo said. Longitudinal studies are underway to look at how loneliness, now associated with an increase in blood pressure, may play a causal role in that increase, he said.

“I’m surprised by the magnitude of the relationship between loneliness and hypertension in this well-controlled cross-sectional study,” said Richard Suzman, director of the Behavioral and Social Research Program at the National Institute on Aging, which helps fund the research. “Older people’s relationships are often disrupted by death, illness and geographic mobility. One of NIA’s goals is to help determine what can be done to improve the quality of relationships and social connectedness as a way to ease loneliness and reduce blood pressure.”

The research was also supported by a grant from the John Templeton Foundation.