Older adults' beliefs about the timeline of type 2 diabetes and adherence to dietary regimens.

The common-sense model posits that behavioural coping with illness is shaped by a complex combination of individuals' abstract and concrete beliefs about their illness. We investigated this theoretical assumption in a study of 116 older adults diagnosed with type 2 diabetes who completed in-person interviews at baseline and six and 12 months later. Specifically, we examined (1) the interaction of patients' abstract and concrete beliefs about the timeline of their diabetes as a predictor of change in adherence to a healthy diet and (2) whether these interactive effects differ among male and female patients. Abstract timeline beliefs were conceptualised as those pertaining to disease duration; concrete timeline beliefs were conceptualised as those pertaining to variability of disease symptoms (i.e. symptoms are stable versus fluctuating). As predicted, duration beliefs were positively associated with improvement in adherence among patients who viewed disease symptoms as stable, but not among those who viewed symptoms as variable. When gender was considered, these interactive effects were observed among male (but not female) patients. Findings revealed that the behavioural effects of men's abstract knowledge about their diabetes were conditioned by their concrete representations of the disease, suggesting a bottom-up process of influence with implications for intervention.