Leukocyte Telomere Length and Risk of Papillary Thyroid Carcinoma

Context: Telomere length may contribute to predisposition to papillary thyroid cancer (PTC). Objective: To test this hypothesis, we examined the association between leukocyte telomere length and PTC risk. Design/Setting: Case-control study in a Chinese Han population. Participants/Intervention: A total of 1200 PTC cases and 1201 age-and sex-matched healthy controls were included in the study. ORs and 95% CIs were calculated by logistic regression. Results: Short relative telomere length (RTL) was significantly associated with elevated risk of PTC (OR = 1.61, 95% CI = 1.35 to 1.92; P = 1.30 x 10(-7)). Interestingly, when individuals were categorized into four groups on the basis of quartile distribution of relative telomere length (RTL) in controls, we observed a reverse U-shaped association between telomere length and PTC risk. Compared with those in the first (the longest) quartile as the reference group, ORs (95% CIs) were 5.61 (4.04 to 7.78) (P = 6.10 x 10(-25)), 9.33 (6.78 to 12.83) (P = 6.99 x 10(-43)), and 1.23 (0.83 to 1.81) (P = 0.300) for individuals in the second, third, and fourth (the shortest) quartiles, respectively. This reverse U-shaped relationship was more apparent in younger individuals. Conclusions: Our findings suggest that RTL is significantly associated with susceptibility to PTC. There is an obvious reverse U-shaped association between telomere length and PTC risk. Telomere length may be a potential pronouncing biomarker to identify individuals with a high risk of developing PTC.