Do you serve rural health professionals? Is there an Area Health Education Center on your campus? Do you serve rural health grant seekers? This National Academies Press online book might be of interest to you and your patrons:
Quality through collaboration: the future of rural health care http://www.nap.edu/books/0309094399/html/
Chapter 6 might be of particular interest to those creating shared libraries to support rural health professionals and consumers. Appendix B covers Characteristics of Rural Populations. The book is free to read online, and is available for purchase in hardback or paperback versions.