Arthritis is generally thought of as a disease that affects elderly people the most, but a new study shows that this is a misperception and that younger people actually are impacted more.

Nearly 40 million people in the U.S. have arthritis, an inflammation of the joints that can occur in anyone, including children, although its likelihood increases with age.

Researchers examined the physical and mental health effects of arthritis in a poll taken of 4,565 Canadian adults aged 75 or older, compared to younger people between the age of 20 and 74 years old.

They tracked how often the respondents experienced the following: joint pain; fatigue; sleep problems; difficulty in daily functioning; high stress levels, and suboptimal general and mental health.

The results showed younger people (aged 20-44) and/or middle-aged adults (45-64) were more likely than the oldest age group (75-plus) to report severe/frequent joint pain, sleep limitations, high stress levels, and suboptimal mental health.

Although people 75 and older were the most likely to report generally poorer health, their problems were most often not related to arthritis, said researchers who published their findings in the journal BMC Musculoskeletal Disorders.