To test repeatability and relative validity of a computerized and interviewer administered assessment.
Using a context-based case-control trial, 41 adults with type 2 diabetes mellitus were randomized into four groups to complete dietary assessments (computerized or interviewer administered) at 0, 2 and 8 weeks and food records at 0 and 2 weeks. Repeatability of reported energy, total fat, saturated, polyunsaturated and monounsaturated fatty acids between the computerized and interviewer administered methods were assessed using repeated measures ANOVA. Paired t-tests and Pearson's correlations determined relative validity of the assessments.
Thirty-one patients completed all visits. Statistically significant differences were found between computerized and interviewer administered data for total fat (p = 0.048) and saturated fatty acids (p = 0.019) between 0 and 2 weeks. Computerized assessments correlated better with food records (r = 0.160.52) compared with interviewer administered assessments (r = 0.02 to 0.51).
Computerized assessments saw a learning effect with repeated use indicating that users were becoming more familiar with the website with repeated use. Relative validity suggests that the website may capture more foods though this requires further investigation.
By allowing patients to self-report their intakes on a computer, dietitians will have the ability to spend increased time with their patients counseling them toward change.
Keywords: Dietary assessment; Dietitian; Computer; Repeatability; Primary healthcare