In this week's Archives of Internal Medicine (September 26, 2005) there is an article on the association between health literacy and self-reported physical and mental health functioning and activity among new Medicare managed care enrollees. They surveyed 2923 people from Cleveland, Ohio; Houston, Tex; Tampa, Fla; and Fort Lauderdale–Miami. It was determined that individuals with inadequate health literacy had worse physical and mental health, more difficulty with daily activities (due to health) and more pain that interfered with work activities.

(Archives of Internal Medicine article)
Health Literacy and Functional Health Status Among Older Adults
Michael S. Wolf; Julie A. Gazmararian; David W. Baker
Arch Intern Med. 2005;165:1946-1952.

Obviously there is a role for health information libraries here. Check out my recent post on Physicians and Health Libraries Helping Patient Literacy where doctors have teamed up community centers and libraries to help improve patient health by improving their literacy skills. Donna Beals also authored a recent article Health Literacy: The Medical Librarian's Role, in the Journal of Hospital Librarianship.