Leukocyte Telomere Length Is Not Reduced in Children and Adults with Cystic Fibrosis but Associates with Clinical Characteristics—A Cross-Sectional Study

We hypothezied that telomere length is considerably altered in cystic fibrosis (CF) patients compared to healthy subjects (HS), and that leukocyte telomere length variation reflects the severity of CF. Relative telomere length (RTL) was assessed by qPCR in 70 children aged 5–10 (34 CF; 36 HS) and 114 adults aged 18–45 (53 CF; 61 HS). Telomere length was similar in CF and HS (median (interquartile range): 0.799 (0.686–0.950) vs. 0.831 (0.707–0.986); p = 0.5283) both in children and adults. In adults, women had longer telomeres than men (0.805 (0.715–0.931) vs. 0.703 (0.574–0.790); p = 0.0002). Patients treated with inhaled corticosteroids had a shorter RTL compared to those without steroid therapy (0.765 (0.664–0.910) vs. 0.943 (0.813–1.191); p = 0.0007) and this finding remained significant after adjusting for gender, age, BMI, and child/adult status (p = 0.0003). Shorter telomeres were independently associated with the presence of comorbidities (0.763 (0.643–0.905) vs. 0.950 (0.783–1.130); p = 0.0006) and antibiotic treatment at the moment of blood sampling (0.762 (0.648–0.908) vs. 0.832 (0.748–1.129); p = 0.0172). RTL correlated with number of multiple-day hospitalizations (rho = −0.251; p = 0.0239), as well as number of hospitalization days (rho = −0.279; p = 0.0113). Leukocyte RTL in children and adults with CF was not shorter than in healthy controls, and did not seem to have any potential as a predictor of CF survival. However, it inversely associated with the investigated clinical characteristics.