Kostas Tsilidis (pictured, left) is an Assistant Professor at the Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Greece, and a Senior Lecturer at the Department of Epidemiology and Biostatistics, Imperial College School of Public Health, UK.
Leandro Rezende is a PhD student at the Department of Preventive Medicine, University of Sao Paulo School of Medicine, Brazil.
Evidence from our recent umbrella review confirmed that physical activity can reduce the risk of colon and breast cancer. Evidence for other cancer sites is less consistent, with hints of uncertainty and bias in the literature.
Our umbrella review on physical activity and cancer, published in November, found strong and highly suggestive evidence that physical activity reduces the risk of colon and breast cancer respectively. This confirms previous findings from the World Cancer Research Fund International Continuous Update Project.
In our research, we also found that physical activity was negatively associated with other types of cancer, such as endometrial, lung, oesophageal, pancreatic and meningioma. However, this evidence was not consistent.
In fact, numerous biases are believed to affect the scientific literature, so our study aimed to use an array of statistical tests and sensitivity analyses to evaluate the robustness of the evidence of the published literature. We found uncertainty and bias in the literature of other cancer sites. Further studies focusing on these cancer sites could help to confirm whether physical activity may also help to prevent these cancers.
Future research in the area of physical activity and cancer should focus on a more valid and unified assessment of physical activity. However, the challenge looking ahead will be to translate existing and future research into policy and action. Physical activity is important for health, but it is really challenging to change behaviour towards regular exercise.
An increase in physical activity should be every individual’s goal, but this change is determined also by social, political and cultural issues. Policies and environmental interventions (eg bicycle pathways, walkable sidewalks, parks and recreational facilities) are essential for supporting sustainable changes in physical activity for large portions of the population.