Relative mean telomere sequence amount was determined by quantitative PCR (qPCR) of peripheral blood leukocyte (PBL) samples obtained at recruitment (n = 310) from individuals from the Osteoarthritis (OA) Initiative consortium. Knees were radiologically evaluated according to the Kellgren-Lawrence (KL) score, ranging from 0 to 4, considering a KL grade ≥ 2 as radiographic evidence of OA (n = 124). Telomere size decreased as baseline KL score increased, being significantly shorter in subjects with KL ≥2 (Mann-Whitney U-test, P < 0.0001). PBL telomere size was also associated with age, hypertension, body mass index (BMI) and waist circumference. Nevertheless, logistic regression analysis showed that PBL telomere size was a consistent risk factor for concurrent knee OA, independent of these health parameters. Shorter PBL telomeres may indicate a premature aging status which enhances chondrocyte senescence and degenerative joint disease. Environ. Mol. Mutagen. 60:298-301, 2019. © 2018 Wiley Periodicals, Inc.