Physical Activity, Exercise, Weight Reduction and Oxidative DNA Damage in Colorectal Cancer Risk Groups. Is there a Hormesis Relationship Between Risk Biomarkers and Lifestyle Factors?

Patients with obesity and/or type 2 diabetes have an increased tumor risk including colorectal cancer.Physical acrtivity (PA), exercise (EX) and weight reduction (WR) are effective strategies to decrease this risk.Highly sensitive tumor risk biomarkers such as oxidative DNA damage products (8-oxo-2'deoxyguanosine [8-oxo-dG]) increasingly are used in epidemiological and clinical (intervention) studies to better quantify this risk and to investigate potential effects of PA/EX/WR on this biomarker with the aim to further improve prevention and patient management programs.Based on the available data a U-shaped relationship between urinary 8-oxo-dG excretion and the level of PA/EX intensity is assumed, on the other hand, the relationship with BMI seems to be less clear.In this minireview this data will be discussed with regard to clinical and epidemiologic aspects.