Cancer beliefs and diet self-management among cancer survivors with comorbid diabetes.

Purpose: Illness beliefs impact disease self-management; however, little is known about the impact of patients' beliefs about one illness on the management of another illness. We sought to understand how cancer beliefs impact diet self-management for cancer survivors with diabetes and whether a change in beliefs leads to a change in dietary adherence.

Methods: Seventy-eight participants with diabetes and recently diagnosed early-stage breast, prostate, lung, or colon cancer were recruited. Participants were surveyed at enrollment and after 12 months about their cancer and diabetes illness beliefs and dietary adherence. Associations between beliefs about cancer and diabetes to diet adherence at baseline and at 12 months were assessed. Change in diet adherence was examined in relation to beliefs about each illness.

Results: The mean age was 62 years, and 23 (32%) identified as black non-Hispanic, 22 (31%) as white non-Hispanic, and 14 (19%) as Hispanic. Participants with more threatening beliefs about both cancer and diabetes at baseline had worse adherence to a diabetes diet than those with less threatening beliefs. However, at 12 months, those with more threatening cancer beliefs had better dietary adherence than participants with less threatening beliefs. Diabetes beliefs were not associated with diet adherence at 12 months.

Conclusions: While threatening illness beliefs may initially result in worse diet adherence, over time these beliefs may result in increased activation for better self-care and improved diet adherence.

Implications For Cancer Survivors: Understanding how cancer beliefs impact diet self-management for diabetes may provide coping strategies to improve cancer survivors' management of comorbidities.