NEW YORK — Americans with disabilities and other chronic conditions are less likely to use the Internet, but those who are online are among the most avid consumers of health-related information, a new study finds.

Half of those with chronic conditions use the Internet, compared with three-quarters of those without, the Pew Internet and American Life Project said Monday.

That's partly because those with chronic conditions tend to be older and less educated, two factors linked with lower Internet usage overall, said Susannah Fox, an associate director at Pew and the study's main author. Other barriers include difficulties navigating the Web for those with, say, poor vision or motion control.

But when they are online, those with chronic conditions are more apt to seek health information online — at least for some tasks.

"It's an indication of what could happen in the future if there were more universal access to the Internet," Fox said. "This population is just as likely as anyone else to take advantage of the technology's promises."

The telephone study of 2,928 American adults was conducted in August 2006 and has a margin of sampling error of plus or minus 2 percentage points. Results based on the 268 Internet users with chronic conditions have an error margin of plus or minus 7 percentage points.

Pew said 86 percent of Internet users with chronic conditions have looked online for information on at least one of 17 health topics, compared with 79 percent of those without such conditions. The difference, however, falls within the error margin.

The study found the chronic population far more likely to look for information about medication, specific treatments and procedures and alternative treatments and medicines — all by margins exceeding the potential sampling error.