Physical activity and risks of breast and colorectal cancer: a Mendelian randomisation analysis.
Papadimitriou N., Dimou N., Tsilidis KK., Banbury B., Martin RM., Lewis SJ., Kazmi N., Robinson TM., Albanes D., Aleksandrova K., Berndt SI., Timothy Bishop D., Brenner H., Buchanan DD., Bueno-de-Mesquita B., Campbell PT., Castellví-Bel S., Chan AT., Chang-Claude J., Ellingjord-Dale M., Figueiredo JC., Gallinger SJ., Giles GG., Giovannucci E., Gruber SB., Gsur A., Hampe J., Hampel H., Harlid S., Harrison TA., Hoffmeister M., Hopper JL., Hsu L., María Huerta J., Huyghe JR., Jenkins MA., Keku TO., Kühn T., La Vecchia C., Le Marchand L., Li CI., Li L., Lindblom A., Lindor NM., Lynch B., Markowitz SD., Masala G., May AM., Milne R., Monninkhof E., Moreno L., Moreno V., Newcomb PA., Offit K., Perduca V., Pharoah PDP., Platz EA., Potter JD., Rennert G., Riboli E., Sánchez M-J., Schmit SL., Schoen RE., Severi G., Sieri S., Slattery ML., Song M., Tangen CM., Thibodeau SN., Travis RC., Trichopoulou A., Ulrich CM., van Duijnhoven FJB., Van Guelpen B., Vodicka P., White E., Wolk A., Woods MO., Wu AH., Peters U., Gunter MJ., Murphy N.
Physical activity has been associated with lower risks of breast and colorectal cancer in epidemiological studies; however, it is unknown if these associations are causal or confounded. In two-sample Mendelian randomisation analyses, using summary genetic data from the UK Biobank and GWA consortia, we found that a one standard deviation increment in average acceleration was associated with lower risks of breast cancer (odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.27 to 0.98, P-value = 0.04) and colorectal cancer (OR: 0.66, 95% CI: 0.48 to 0.90, P-value = 0.01). We found similar magnitude inverse associations for estrogen positive (ER+ve) breast cancer and for colon cancer. Our results support a potentially causal relationship between higher physical activity levels and lower risks of breast cancer and colorectal cancer. Based on these data, the promotion of physical activity is probably an effective strategy in the primary prevention of these commonly diagnosed cancers.