RT Journal Article T1 Effect of time of day of recreational and household physical activity on prostate and breast cancer risk (MCC-Spain study) A1 Weitzer, Jakob A1 Castaño Vinyals, Gemma A1 Aragonés, Nuria A1 Alguacil Ojeda, Juan AB Experimental evidence indicates that exercise performed at different times of the daymay affect circadian rhythms and circadian disruption has been linked to breast andprostate cancer. We examined in a population-based case-control study (MCC-Spain)if the time-of-day when physical activity is done affects prostate and breast cancerrisk. Lifetime recreational and household physical activity was assessed by in-personinterviews. Information on time-of-day of activity (assessed approximately 3 yearsafter the assessment of lifetime physical activity and confounders) was available for781 breast cancer cases, 865 population female controls, 504 prostate cases and645 population male controls from 10 Spanish regions, 2008-2013. We estimatedodds ratios (ORs) and 95% confidence intervals (95% CI) for different activity timingscompared to inactive subjects using unconditional logistic regression adjusting forconfounders. Early morning (8-10 AM) activity was associated with a protective effectcompared to no physical activity for both breast (OR = 0.74, 95% CI = 0.48-1.15) andprostate cancer (OR = 0.73, 95% CI = 0.44-1.20); meta-OR for the two cancers combined0.74 (95%CI = 0.53-1.02). There was no effect observed for breast or prostatecancer for late morning to afternoon activity while a protective effect was alsoobserved for evening activity only for prostate cancer (OR = 0.75, 95% CI = 0.45-1.24).Protective effects of early morning activity were more pronounced for intermediate/evening chronotypes for both cancers. This is the first population-based investigationidentifying a differential effect of timing of physical activity on cancer risk with morepronounced effects for morning hour activity. Our results, if confirmed, may improvecurrent physical activity recommendations for cancer prevention. PB Wiley SN 1097-0215 YR 2020 FD 2020-10 LK http://hdl.handle.net/10272/18996 UL http://hdl.handle.net/10272/18996 LA eng NO Weitzer, J., Castaño Vinyals, G., Aragonés, N. ... Alguacil Ojeda, J. (2020). Effect of time of day of recreational and household physical activity on prostate and breast cancer risk ( MCC‐Spain study). International Journal of Cancer. DOI: https://doi.org/10.1002/ijc.33310 NO Instituto de Salud Carlos III, Grant/AwardNumbers: PI11/01889, PI08/1770,PI08/0533, PI08/1359, PS09/00773,PS09/01286, PS09/01903, PS09/02078,PS09/01662, PI11/02213, PI12/00488,PI12/01270Fundación Marqués de Valdecilla,Grant/Award Number: API 10/09ICGCInternational Cancer Genome Consortium CLL(The ICGC CLL-Genome Project is funded bySpanish Ministerio de Economía yCompetitividad (MINECO) through theInstituto de Salud Carlos III (ISCIII) and RedTemática de Investigación del Cáncer (RTICC)del ISCIII), Grant/Award Number:RD12/0036/0036Junta de Castilla y León,Grant/Award Number: LE22A10-2Consejeríade Salud of the Junta de Andalucía, Grant/Award Numbers: PI-0571-2009, PI-0306-2011,salud201200057018traConselleria de Sanitat ofthe Generalitat Valenciana, Grant/AwardNumber: AP_061/10Recercaixa, Grant/AwardNumber: 2010ACUP 00310RegionalGovernment of the Basque CountryConsejeríade Sanidad de la Región de MurciaEuropeanCommission, Grant/Award Number: FOOD-CT 2006-036224-HIWATESpanish AssociationAgainst Cancer (AECC) ScientificFoundationCatalan Government-Agency forManagement of University and Research Grants(AGAUR), Grant/Award Numbers: 2017SGR723,2014SGR850Fundación Caja de Ahorros deAsturias and by the University of OviedoSpanishMinistry of Science and Innovation through the“Centro de Excelencia Severo Ochoa2019-2023” Program, Grant/Award Number:CEX2018-000806-SGeneralitat de Catalunyathrough the CERCA Program DS Repositorio Institucional de la Universidad de Huelva RD 30 may 2026