Higher prevalence of fibromyalgia in patients infected with human T cell lymphotropic virus type I

. Inflammatory rheumatic conditions including rheumatoid arthritis and Sjögren's syndrome have been reported in individuals infected with human T cell lymphotropic virus type I (HTLV-I). Other chronic lymphotropic virus infections such as hepatitis C and human immunodeficiency virus are associated with fibromyalgia (FM). There are no reports about the association between HTLV-I infection and FM. We evaluated the association between FM and HTLV-I infection.

We conducted a case-control study with prevalent cases. Ex-blood donation candidates with HTLV-I infection from a blood bank cohort, and healthy blood donors as a control group, were submitted to rheumatologic evaluation to compare the prevalence of FM. The following covariables were also evaluated: other rheumatic diseases, age, sex, personal income, level of education, and depression.

One hundred individuals with HTLV-I infection and 62 non-infected blood donors were studied. Thirty-eight (38%) HTLV-I infected individuals and 3 (4.8%) individuals from the control group presented the diagnosis of FM (OR 12.05, 95% CI 3.53-41.17). Other rheumatic diseases were also more prevalent in the infected group (37% vs 12.9%; OR 3.80, 95% CI 1.63-8.86). In multivariate analysis adjusted by the covariables, the association between HTLV-I and FM was statistically significant (OR 9.14, 95% CI 2.42-34.52).

Our study shows a greater prevalence of FM in HTLV-I infected individuals, suggesting that FM may be associated with this viral infection.