Nov. 10 (HealthDay News) -- Arthritis-related disability can have a major impact on a person's employment, forcing them to change work hours, the type and nature of their work, or even lose their job, a Canadian study reports.

The study tracked 490 people with osteoarthritis (OA) and inflammatory arthritis (IA) for more than four years. During that time, 63 percent of the participants remained employed, but work changes were common: 45 percent reduced their work hours due to arthritis; 52 percent switched their type of work; 18 percent weren't able to seek and accept promotions and job transfers; and 41 percent weren't able to take on additional responsibilities.

In addition, many of the participants used vacation time and missed work to deal with their arthritis.

"We know that arthritis can result in people having to leave their jobs. This research focuses our attention on the workplace itself and highlights how common a wide range of work transitions are in the lives of people with arthritis," Monique A.M. Gignac, senior scientist at the Toronto Western Research Institute and associate professor in the department of health sciences at the University of Toronto, said in a prepared statement.

"By studying these changes, we hope to identify those that allow people to remain employed longer, as well as types of transitions that signal problems that need to be addressed with early intervention and treatment," she said.

The study was expected to be presented Nov. 10 at an American College of Rheumatology meeting in Boston.

Arthritis affects about 46 million Americans.

SOURCE: American College of Rheumatology, news release, Nov. 7, 2008