Researchers say it might not be just the pain that’s leading to insomnia, reports Reuters Health.

“Although we know that people with chronic pain are more likely to report problems sleeping than people without any pain, we know very little about how the presence of pain leads to the development of insomnia,” said Tang.

Tang and her team mailed questionnaires to all people age 50 or older registered with general medical practices in North Staffordshire, U.K.