RESUMEN
Telomere length has been associated with risk of several cancers. However, studies of the relationship between telomere length and colorectal cancer risk have been inconsistent. This study examined the relationship between telomere length in normal colon tissue and the prevalence of colorectal adenoma, a precursor to colorectal cancer. This nested case-control study consisted of 85 patients aged 40 to 65 undergoing a screening colonoscopy: 40 cases with adenoma(s) detected at colonoscopy and 45 controls with normal colonoscopy. During the colonoscopy, two pinch biopsies of healthy, normal appearing mucosa were obtained from the descending colon. Relative telomere length (rTL) was quantified in DNA extracted from colon mucosa using quantitative real-time PCR. Logistic regression was used to assess the relationship between telomere length and adenoma prevalence and estimate odds ratios and 95% confidence intervals. rTL was significantly longer in colon tissue of individuals with adenomas compared to healthy individuals (p = 0.008). When rTL was categorized into quartiles according to the distribution of rTL among controls, individuals with the longest telomeres had increased odds of adenoma when compared to individuals with shortest telomeres (OR = 4.58, 95% CI: 1.19, 17.7). This study suggests that long telomeres in normal colon tissue are associated with increased colorectal cancer risk.
Asunto(s)
Adenoma/genética , Neoplasias Colorrectales/genética , Predisposición Genética a la Enfermedad/epidemiología , Telómero/genética , Adenoma/epidemiología , Adenoma/patología , Adulto , Biopsia , Carcinogénesis/genética , Estudios de Casos y Controles , Colon/diagnóstico por imagen , Colon/patología , Colonoscopía , Neoplasias Colorrectales/diagnóstico por imagen , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/patología , Femenino , Humanos , Mucosa Intestinal/diagnóstico por imagen , Mucosa Intestinal/patología , Masculino , Persona de Mediana Edad , Prevalencia , Reacción en Cadena en Tiempo Real de la Polimerasa , Factores de RiesgoRESUMEN
BACKGROUND: Telomeres protect from DNA degradation and maintain chromosomal stability. Short telomeres have been associated with an increased risk of cancer at several sites. However, there is limited knowledge about the lifestyle determinants of telomere length. We aimed to determine the effect of three factors, known to be important in cancer etiology, on relative leukocyte telomere length (rLTL): alcohol consumption, smoking, and physical activity. METHODS: This cross-sectional study included 477 healthy volunteers ages 20 to 50 years who completed a questionnaire and provided a fasting blood sample. Multiplex quantitative real-time PCR (qPCR) was used to measure rLTL. Regression coefficients were calculated using multiple linear regression while controlling for important covariates. RESULTS: There was no association between alcohol consumption and rLTL. Daily smokers and those in the middle and lower tertile of pack-years smoking had shorter rLTL than never daily smokers (P = 0.02). Data were suggestive of a linear trend with total physical activity (P = 0.06). Compared with the lowest quartile, the highest quartile of vigorous physical activity was associated with longer rLTL. A significant linear trend of increasing rLTL with increasing vigorous physical activity was observed (P = 0.02). CONCLUSIONS: Cigarette smoking and vigorous physical activity have an impact on telomere length. Smoking was related to shorter telomere length while vigorous physical activity was related to longer telomeres. IMPACT: The findings from this study suggest that lifestyle may play an important role in telomere dynamics and also suggest that engaging in healthy behaviors may mitigate the effect of harmful behaviors on telomere length.