UPDATE: In 2003, Stanford's Laurence Baker, PhD, conducted similar research and found that 40 percent of adults with online access used the Internet for health purposes.
Fifty-one percent of Americans ages 18 to 64 searched online for health information during the past 12 months, according to a survey by the National Center for Health Statistics.
In analyzing data collected during January through June 2009 from 7,192 adults, researchers also found:
Women were more likely than men to look up health information on the Internet (58.0% versus 43.4%) and were also more likely to use online chat groups to learn about health topics (4.1% versus 2.5%).
Women were [also] more likely than men to request a prescription refill on the Internet (6.6% versus 5.3%), make an appointment using the Internet (3.5% versus 1.8%), and communicate with a health care provider over e-mail (5.6% versus 4.2 %).
While more than half of adults turned to the Internet for medical advice, only 5 percent e-mailed their physician. Primary care physician and medical blogger Rob Lamberts, MD and others have speculated that concerns about patient privacy and billing challenges have made doctors reluctant to use e-mail or adapt other technologies.