Cognitive determinants of weight control by dietary patterns among postmenopausal women with osteoporosis: An application of theory of planned behavior.

In this study, we aimed to assess the cognitive determinants of weight control behaviors by dietary patterns among postmenopausal women with osteoporosis. This cross-sectional study, based on the theory of planned behavior (TPB) was conducted from July to December 2017 among 240 postmenopausal women with osteoporosis in Tabriz, Iran. A validated and reliable TPB-based instrument, namely Weight-CuRB, and the food frequency questionnaire (FFQ) were used. The results of exploratory factor analysis (EFA) indicated three dietary patterns (total variance explained=24.44%); healthy (n=71), mixed (n=78), and western (n=91). In addition, food items consumed by participants were classified into twenty-two food groups for dietary pattern analysis. In the healthy and western dietary patterns, attitude (β: 0.140, <0.001) and subjective norms (SNs) (β: 0.498, <0.01) were the only predictors of weight control behavior, respectively. In the women with healthy and western patterns, the TPB-based variables altogether explained 11% and 16% of variations in the behavior, respectively. Among all patients, the TPB-based variables explained 12.2% of variations in weight control behavior, within which SNs were the only significant predictor of the behavior (β=-0.199, <0.01). Our findings highlighted the remarkable role of dietary patterns in the associations between weight control and its cognitive determinants. Dietary patterns should be considered while designing weight control educational interventions among women with osteoporosis. In such interventions, promoting SNs and perceived behavioral control (PBC) should be considered as the core strategies to promote the behaviors among the patients who follow an unhealthy diet.