Telomeres are regions of repetitive DNA at the end of human chromosomes, which protect the end of the chromosome from damage.
Whilst shorter telomeres are hypothesized biological markers of older age and have been linked to many diseases, including cancer and cardiovascular diseases, whether these associations are causal is unknown.
A team at the University of Bristol recently investigated the effect of longer telomeres on the risk of 83 diseases, including cancer, cardiovascular diseases, diabetes, psychiatric diseases and autoimmune diseases in 420,081 cases and 1,093,105 controls.
They used a novel approach known as “Mendelian randomization”.
The research team found that longer telomeres appeared to increase the risk for several cancers, including glioma, serous low-malignant-potential ovarian cancer, lung adenocarcinoma, neuroblastoma, bladder cancer, melanoma, testicular cancer, kidney cancer and endometrial cancer but to decrease the risk for coronary heart disease, abdominal aortic aneurysm, coeliac disease and interstitial lung disease.
The lead author said: “These findings suggest that potential clinical applications based on telomere length may have to consider a trade-off in risk between cancer and other diseases.”
“For example, several companies offer telomere length measurement services to the public, claiming that shorter telomeres are a general indicator of poorer health status and older biological age and that such information can be used to motivate healthy lifestyle choices in individuals.”
“However, the conflicting direction of association between telomere length and risk of cancer and other diseases suggests that such services to the public may be premature”
A co-author added: “Our research has shown that having longer telomeres might increase the risk of some cancers, but reduce the risk for some non-neoplastic diseases, including cardiovascular disease.
“In particular, having genetically-predicted longer telomeres appears to give the highest relative risk for the brain tumor glioma compared with other cancers. This is important because the risk factors for glioma are not well understood now.”
“Currently the well-recognized risk factors for glioma include having had previous radiotherapy and rare cancer genetic syndromes such as Li-Fraumeni syndrome.”
The research suggests that it is likely that longer telomeres increase the risk for several cancers but reduce risk for other diseases, including cardiovascular diseases.
News source: University of Bristol. The content is edited for length and style purposes.
Figure legend: This Knowridge.com image is credited to Stanford University.