2 May 2005
Loneliness Can Make You Sick
by George Atkinson

A study presented at the American Heart Association's Annual Conference suggests that men who are socially isolated have elevated levels of inflammatory markers that are linked to cardiovascular disease. "Our analyses suggest that it may be good for the heart to be connected," said Eric B. Loucks from the Harvard School of Public Health in Boston. "In general, it seems to be good for health to have close friends and family, to be connected to community groups or religious organizations, and to have a close partner."

The researchers studied more than 3000 participants whose blood concentrations of four inflammatory markers were measured. The researchers asked the participants questions about their social network that included: their marital status; the number of relatives in whom they can confide private matters; the number of close friends in whom they can confide private matters; their involvement in religious meetings or services and participation in groups such as senior centers.

After considering major known risk factors for heart disease, men with the lowest level of social involvement had the highest levels of the inflammatory marker interleukin-6. Previous studies have found that inflammation plays a role in causing atherosclerosis. "It seems to allow white blood cells to tether to and become engulfed in the side of the blood vessel wall," Loucks said. "This allows lipids to be deposited in the blood vessel wall more easily, causing atherosclerosis." Interestingly, no link between loneliness and inflammatory markers was found in women. The researchers believe the inflammatory markers may be elevated in men as social isolation may influence health behaviors such as smoking and physical activity and socially isolated people are often depressed and under more stress than their more outgoing counterparts.

In a second study, Carnegie Mellon University researchers found that lonely first-year college students mounted a weaker immune response to the flu-shot than did other students. The study, appearing in the journal Health Psychology, suggests that social isolation (measured by the size of a student's social network) and feelings of loneliness, each independently compromised the students' immunity. The researchers suggest that both objective and subjective aspects of social life are related to health.

For the study, the subjects got their first-ever flu shots at a university clinic and filled out questionnaires on health behavior. For two weeks starting two days before vaccination, they recorded their sense of loneliness, stress levels and mood. The researchers assessed blood samples drawn just before the flu shot and one and four months later for antibody levels, which indicated how well the students' immune systems mounted a response to the multi-strain flu vaccine.

Sparse social ties were associated at a level of statistical significance with poorer immune response to one component of the vaccine, independent of feelings of loneliness. Loneliness was also associated with a poorer immune response to the same strain - as late as four months after the shot. This suggests that chronic loneliness can help to predict health and well-being. The independence of social-network size and loneliness as factors in immunity is supported by the observation that, says Pressman, "You can have very few friends but still not feel lonely. Alternatively, you can have many friends yet feel lonely."

The findings reinforce the knowledge that social factors are important for health, in part because, says Pressman, "they may encourage good health behaviors such as eating, sleeping and exercising well, and they may buffer the stress response to negative events."

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