Digest commentators: Nicole Culos-Reed and Heather Leach, University of Calgary

Digest editor: Jennifer Brunet, University of Ottawa

Many prostate cancer (PC) and breast cancer (BC) survivors are interested in optimizing their health through lifestyle behaviors. The use of health behavior theories can help to understand patterns of nutrition and physical activity following a cancer diagnosis. In this study, predictors from the Commonsense Self-Regulation Model (CSM) and the Transtheoretical Model (TTM) were examined for associations with adherence to physical activity (PA) and healthy diet in PC or BC survivors. PA was measured using the International Physical Activity Questionnaire (IPAQ), assessing PA in the past seven days. Nutrition was assessed using the Past Seven Days Nutrition, assigning a score of 0-6, with higher scores indicating healthier eating guidelines adhered to. Participants were also asked the extent to which their diet and PA behavior had changed since diagnosis, and their preferences for interventions. CSM constructs were measured by the Illness Perception Questionnaire-Revised (IPQR). TTM constructs were represented by a previously developed scale that measured exercise stage of change, which ranges from pre-contemplation (not thinking about exercise), through contemplation, preparation (making small steps towards regular exercise), action (exercising regularly), to maintenance (over 6 months of regular exercise). Self-efficacy was measured using the Exercise and Nutrition Self-Efficacy Scales. Participants in this study were ninety-two men with PC (M age=66.6±7.7 years) and 145 women (M age=56.8±10.5 years) with BC. The median time since diagnosis was 30.0 months for PC and 53.5 months for BC participants. PA guidelines were met by 88% of PC and 85% of BC participants based on self-reported data. PC respondents met on average 2.2 healthy eating guidelines and BC respondents met 2.7. Higher self-efficacy and stage of change from the TTM model were associated with increased PA and greater adherence to nutritional guidelines. Increased PA since diagnosis was associated with higher stage of change and lower illness identity and higher personal control. Healthier eating since diagnosis was associated with longer time since diagnosis, higher stage of change, and higher personal control and higher negative emotional representations. The majority of participants indicated they would be very interested in receiving interventions to assist with improving nutrition or PA, and that they would prefer these interventions at the time of diagnosis or soon after. The associations between a higher TTM stage of change and self-efficacy with adherence were consistent with findings of other studies that have examined PA and healthy eating. No CSM variables were associated with adherence, but some did predict changes in health behaviors. Lower illness identity was associated with increased PA after diagnosis, which suggests that cancer related symptoms may act as a barrier to PA. Higher negative emotions related to cancer was associated with improved post diagnosis diet, suggesting that concerns about cancer may motivate healthy eating behaviors. Associations between higher personal and treatment control beliefs and improved health behaviors since diagnosis suggests that PC and BC survivors are more likely to change health behaviors if they believe that their actions can make a difference in their cancer outcome. The application of theoretical models to explain health behaviors can enhance knowledge of how to provide effective support for the PA and healthy eating needs of PC and BC survivors.

Green HJ, Steinnagel G, Morris C & Laakso EL (2014). Health behaviour models and patient preferences regarding nutrition and physical activity after breast or prostate cancer diagnosis. European Journal of Cancer Care. Advance online publication. doi:10.1111/ecc.12190.

Journal website: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2354

Author website: http://www.griffith.edu.au/health/school-applied-psychology/staff/dr-heather-green