Would the Transtheoretical Model facilitate better adherence to the Dietary Approaches to Stop Hypertension (DASH) diet?

Background: Although the DASH diet reduces blood pressure (BP), adherence to the diet can be difficult to achieve. Interventions based on the Transtheoretical model (TTM) are effective in promoting many behavioral changes, including diet, and hold promise for increasing adherence to DASH among individuals with uncontrolled hypertension. We evaluated the relationship between DASH diet adherence and the core constructs of the TTM, such as decisional balance (DB), self-efficacy (SE) and stage of change (SOC).

Methods: The Willett Food Frequency Questionnaire was administered to 175 hypertensive veterans. Adherence was assessed using a DASH index score (DAI; 0-100) based on adherence to 10 components central to the DASH diet. TTM constructs were assessed using validated measures modified to address diet adherence. Using linear regression, we evaluated whether different levels of TTM constructs were associated with DASH adherence.

Results: Both SE and DB were significant predictors of DAI with a 1-point increase in each associated with .69 (p<.01) and .48 (p<.05) increases in DAI respectively. Additionally, progression through SOC was positively associated with adherence (p<.0001), with an advancement of 1 stage associated with a 2.97 point increase in the DAI.

Conclusions: The core constructs of TTM are associated with improved adherence to the DASH diet. This finding provides empirical support for the use of TTM-based behavioral interventions to promote adherence to the DASH diet. Since diet is a critical component of hypertension treatment, this approach has the potential to lower BP in the large population of individuals with uncontrolled hypertension.