Fibromyalgia: Family Study

A Controlled Family Study in Patients with Fibromyalgia
Principal investigator: Lesley M. Arnold, M.D.

Goal of study: To compare the prevalence of fibromyalgia and mood disorders among the family members of people with fibromyalgia with the prevalence of those disorders among the family members of people with rheumatoid arthritis.
Description: Recent studies with small numbers of participants suggest that fibromyalgia runs in families. Previous studies also suggest that people with fibromyalgia are more likely to have relatives with major mood disorders (such as major depression and bipolar disorder) than other people with chronic pain conditions, such as rheumatoid arthritis.
To explore and further test those results with a large group of participants, Dr. Arnold and her colleagues interviewed 78 people with fibromyalgia and collected information about more than 500 of their relatives to determine the prevalence of fibromyalgia and mood disorders in the family members. For comparison, her team also interviewed 40 people with rheumatoid arthritis and collected information about 272 of their relatives.
The researchers needed to study people with rheumatoid arthritis to create a control group, which reduces the possibility of bias in a study. Collecting the same information from the rheumatoid arthritis group that they take from the fibromyalgia group allows the researchers to compare the fibromyalgia data with that of people who do not have fibromyalgia but are similar to them in terms of background characteristics and treatment-seeking behavior.
Progress and conclusions: The researchers found that fibromyalgia aggregates in families, which means that the family members of people with fibromyalgia were much more likely to have fibromyalgia than family members of people with rheumatoid arthritis.
The team also found that fibromyalgia coaggregates with major mood disorders in families, which means that the family members of those with fibromyalgia were much more likely to have a major mood disorder than the family members of those who have rheumatoid arthritis.
The researchers say one implication of these findings is that genetic factors may play a role in fibromyalgia. In addition, they speculate that mood disorders and fibromyalgia may share some inherited factors.

This study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases.