The Diet Quality Index-Revised: a tool to promote and evaluate dietary change among older cancer survivors enrolled in a home-based intervention trial

Abstract

Objective: To utilize the Diet Quality Index-Revised (DQI-R) as a framework for delivering and evaluating an intervention to improve overall diet quality among older cancer survivors.

Design: As part of a randomized controlled trial to improve lifestyle behaviors among older cancer survivors, we sought a dietary measure that could serve as both an intervention framework and a means to evaluate global dietary quality. The DQI-R measures overall diet quality by summing 10 subscales that relate to national guidelines. At baseline, DQI-R scores were generated from three multi-pass 24-hour dietary recalls. The 6-month intervention delivered tailored feedback on individual DQI-R subscales. Dietary recalls were repeated at 6 and 12 months.

Subjects: Elderly (aged >or=65 years) individuals within 18 months of diagnosis of breast or prostate cancer (n=182) were randomized postbaseline measures to intervention vs attention control arms.

Results: Significant differences in overall diet quality were observed between arms at 6 months, with the intervention arm improving (67.6+/-12.2 to 69.8+/-13.9), and controls declining (67.5+/-12.5 to 64.6+/-14.7) (P=0.003). Significant differences were observed between arms over time in dietary diversity subscale scores: baseline and 6-month follow-up means among intervention and control arms were 4.8+/-1.3 to 4.8+/-1.4, and 4.7+/-1.2 to 4.1+/-1.1, respectively (P=0.001).

Conclusions: The DQI-R served as an effective guide and evaluation tool for this diet-related randomized controlled trial. Like many interventions, our effect diminished after the intervention was complete. Future research should consider testing interventions that use the DQI-R, or other global diet-related indexes, as guides and evaluation tools over longer study periods, as well as in other populations.