Peripheral Blood Leukocyte Telomere Length and Endometriosis.

Endometriosis is a common gynecologic disease defined by the presence of endometrial-like tissue outside the uterine cavity. While its etiology is largely unknown, accumulating evidence suggests that inflammation plays a major role. Our objective was to investigate the association between peripheral blood leukocyte telomere length (LTL) and endometriosis using data from two large population-based studies, the New England Case-Control Study (NEC; n = 877) and the National Health and Nutrition Examination Survey (NHANES; n = 2268). NEC control participants were identified through a combination of random digit dialing, drivers' license lists, and town resident lists. In NHANES, selection algorithms were used to identify a nationally representative sample. Blood samples and demographic, reproductive, and health-related information were available from both data sources. Endometriosis was defined as self-reported of physician-diagnosed endometriosis. LTL was measured using quantitative polymerase chain reaction. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI) for the association between LTL and endometriosis. Shorter LTL was associated with greater odds of history of endometriosis. In NEC, women with the shortest LTL tertile compared with the longest had a 2.5-fold greater odds of endometriosis (OR _T3/T1  = 2.56, 95% CI = 1.16-5.63; p value, test for linear trend = 0.02). The association was stronger among women who usually experienced moderate or severe menstrual pain (OR _T3/T1  = 3.50, 95% CI = 1.12-10.97). In NHANES, the data suggested a similar but attenuated association (OR _T3/T1  = 1.29, 95% CI = 0.85-1.96). The observed associations in NEC suggest that shorter LTL may be associated with greater odds of endometriosis. A better understanding of how LTL influences endometriosis risk could elucidate novel disease pathophysiology.