Background and Objective: For nearly a century, it has been suspected that reproductive tract infections play an etiologic role in uterine leiomyoma. However, no epidemiologic study of leiomyoma has used the polymerase chain reaction (PCR) to compare uterine tissues from cases and non-cases, and to investigate associations between uterine leiomyoma and infections detected by PCR.
Methods: In this case-control study, 92 leiomyoma tissues from cases, and 94 myometrial tissue from controls were screened by PCR for cytomegalovirus, Chlamydia trachomatis, herpes simplex virus-1, 2, and human papillomavirus typed as 16/18 or another strain. Multivariable analysis used age-adjusted logistic regression, and generalized linear regression as appropriate.
Results: In the uterine tissues of cases and unmatched controls, the prevalence of infection was: cytomegalovirus (32.6%, 7.4%), C. trachomatis (23.9%, 37.2%), herpes simplex virus-1,2 (25.0%, 13.8%), human papillomavirus 16/18 (13.0%, 10.5%). Leiomyoma was associated with cytomegalovirus (Odds Ratio (O.R.) 6.10; 95% confidence interval (C.I.), 2.40, 15.55) and Chlamydia (O.R. 0.47; 95% C.I. 0.23, 0.97). Likewise, the log count of leiomyoma was higher with cytomegalovirus (+0.65, 95% C.I. +0.34, +0.95) and lower with Chlamydia (-0.71, 95% C.I. -1.12, -0.29).
Conclusion: This first application of PCR to leiomyomata and control uterine tissues from non-cases reveals that cytomegalovirus is associated with the presence, number, and volume of uterine leiomyoma, while C. trachomatis is inversely associated with leiomyoma, but only in the absence of cytomegalovirus. Current findings provide preliminary evidence that common reproductive tract infections contribute to the growth and control of at least some cases of uterine leiomyoma.