['Telomeres are nucleoprotein structures that cap the end of chromosomes and shorten with sequential cell divisions in normal aging. Short telomeres are also implicated in the incidence of many cancers, but the evidence is not conclusive for colorectal cancer (CRC). Therefore, the aim of this study was to assess the association of CRC and telomere length.', 'In this case-control study, we measured relative telomere length from peripheral blood leukocytes (PBLs) DNA with quantitative PCR in 598 CRC patients and 2,212 healthy controls.', 'Multivariate analysis indicated that telomere length was associated with risk for CRC, and this association varied in an age-related manner; younger individuals (≤50 years of age) with longer telomeres (80-99 percentiles) had a 2-6 times higher risk of CRC, while older individuals (>50 years of age) with shortened telomeres (1-10 percentiles) had 2-12 times the risk for CRC. The risk for CRC varies with extremes in telomere length in an age-associated manner.'] Does the association of telomere length with colorectal cancer differ by the age of cancer onset?