Image of Ruth A. Hackett, Ph.D.

The lack of high-quality personal connections may help predict who will develop type 2 diabetes later in life, even when other major risk factors are accounted for, a new study shows. Helping older adults form and experience positive relationships could help prevent the disease, the researchers say.

Ruth A. Hackett, Ph.D., and colleagues from King’s College London analyzed about 15 years of health data from 4,112 adult participants in the English Longitudinal Study of Aging. Participants initially were diabetes-free and had normal blood glucose levels.

Over 12 years, 264 developed type 2 diabetes. Loneliness measured at the study’s start was found to be a significant predictor of later disease onset. But there was a “clear distinction” between loneliness and social isolation, Hackett noted. Isolation or living alone did not predispose participants to diabetes, but loneliness, defined by the quality of relationships, did, she said.

The results accounted for smoking, alcohol, weight, level of blood glucose, high blood pressure and cardiovascular disease. The association also was independent of depression, living alone and social isolation, Hackett reported.

The researchers proposed two possible explanations for the findings. Constant loneliness produces stress, eventually affecting the body and possibly increasing the risk for diabetes, Hackett proposed. Thinking biases also may affect risk, she said. When people feel lonely, they may have more difficulty forming good relationships.

“If the feeling of loneliness becomes chronic, then every day you’re stimulating the stress system,” Hackett explained. “[O]ver time, that leads to wear and tear on your body and those negative changes in stress-related biology may be linked to type 2 diabetes development.”

The study was published Tuesday in the journal Diabetologia.