New research shows that aging women who sleep well and/or have strong social ties have lower levels of interleukin-6, an immune system protein that promotes inflammation and that tends to increase with age.
Interleukin-6 (IL-6) has been linked to a variety of diseases including osteoporosis, rheumatoid arthritis, heart disease, Alzheimer’s disease, and cancer. People who have relatively high levels of IL-6 are at greater risk for these diseases.
“The bottom line” said Dr. Elliot M. Friedman, “is that while poor quality sleep and low quality social relationships increase the risk of higher levels of IL-6 and, thereby, age-related disease, you don’t need to have both in order to have low levels of IL-6 -- having high levels of one is enough.”
Friedman, from the University of Wisconsin in Madison, and colleagues examined the interplay between social engagement, sleep quality, and blood levels of IL-6 in 74 women between the ages of 61 and 90. The team reports their research in the early online issue of the Proceedings of the National Academy of Sciences.
“Our goal was to find out if there are psychological factors that might protect people against high levels of IL-6 as they age and we had two interesting findings,” Friedman told Reuters Health.
“First, we found that sleep quality and social relationships appear to be protective against high levels of IL-6, even after accounting for other factors that could affect IL-6 levels, such as chronic illness, obesity, and smoking,” he reported. Women who slept well had low levels of IL-6, as did women who reported strong social relationships, Friedman further explained.
But having either good social relationships or good sleep quality appears to compensate for difficulties with the other. That is, IL-6 levels were only higher in women who slept poorly and who reported poor quality social relationships.
The researcher admitted that he was surprised by this compensatory relationship. “I would have expected an additive effect: that is having both good sleep and good social ties would be better than having one or the other, and having one would be better than having neither.”
The fact that good social ties can compensate for poor sleep, and vice versa, suggests a more complex relationship between these psychological and biological factors -- “which also means that we have lots more exciting work to do to figure out why this is,” Friedman said.