Dairy intake screener as web-based application is reliable and valid.

Area of Science:

• Nutrition Science
• Dietary Assessment
• Public Health

Background:

• Accurate assessment of dietary intake is crucial for nutritional research and public health.
• Web-based screeners offer a convenient method for collecting dietary data.
• The reliability and validity of the "Dairy Diary" web-based dairy intake screener were previously unevaluated.

Purpose of the Study:

• To evaluate the test-retest reliability of the "Dairy Diary" screener.
• To assess the comparative validity of the "Dairy Diary" screener against weighed food records.
• To determine the diagnostic accuracy of the "Dairy Diary" for screening dairy intake.

Main Methods:

• A diagnostic accuracy study was conducted with 79 undergraduate nutrition students in South Africa.
• Participants completed 3 days of weighed food records (reference) and two administrations of the "Dairy Diary" screener (index test) 2 weeks apart.
• Statistical analyses included t-tests, correlations, Bland-Altman, Kappa statistics, McNemar's tests, and ROC curve analysis.

Main Results:

• The "Dairy Diary" demonstrated strong test-retest reliability for individual dairy product serving scores (PSSs) (r = 0.69–0.74) and moderate reliability for summative dairy serving scores (DSSs) (Kappa = 0.45).
• Comparative validity showed moderate correlations for PSSs (r = 0.30–0.38) and DSSs (Kappa = 0.31) against weighed food records.
• Categorized DSSs exhibited high sensitivity (81.4%) and positive predictive value (93.4%), with acceptable overall diagnostic accuracy (AUC = 0.7).

Conclusions:

• The "Dairy Diary" is a reliable tool for repeated dairy intake assessments.
• The screener demonstrates moderate comparative validity, suitable for screening dairy intake in nutrition-literate populations.
• While sensitive for identifying intake, its lower specificity suggests caution in interpreting negative results.