Skin Carotenoid Score Level and Race Affect Intradevice Repeatability of Veggie Meter® at a Single Time Point
Saima Hasnin1, Stephanie B Jilcott Pitts2, Charlotte K Roman3
1Department of Food Science and Human Nutrition, University of Illinois Urbana-Champaign, Urbana, IL; Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL.
Objective:
To compare the reliability of 2 methods (3 scan average vs average of scan 2 and 3) of skin carotenoid score (SCS) measurement and identify participant-level factors affecting intradevice repeatability of Veggie Meter® (VM).
Design:
Cross-sectional study in Illinois.
Participants:
The sample (N = 587) included about 36% children, 27% adolescents, and 32% adults; 67% were White, 14% Asian, 10% Black or African American, 8% mixed race, 1% Native Hawaiian, and 0.4% American Indian; 92% were non-Hispanic, and 53% female.
Variable Measured:
Three consecutive SCS readings using 2 devices. Self-reported or parent-reported demographic information.
Analysis:
Paired sample t-tests compared the coefficient of variation of the 3-scan average SCS with the coefficient of variation of the second and third-scan average SCS. We conducted sign tests and generated Bland-Altman plots to determine the type of errors. Kruskal-Wallis and Mann-Whitney tests assessed if repeatability coefficients of the 3 consecutive SCS readings were different across age, race, ethnicity, and SCS quartiles, where repeatability coefficients = within-subject SD × √2 × 1.96.
Results:
Averaging the second and third scans of SCS produced 1.2% higher reliability in VM 1 and 0.7% higher reliability in VM 2 than averaging all 3 scans (tVM 1 = -7.1, P < 0.001; tVM 2 = -3.1, P = 0.002). Repeatability coefficients were significantly higher among participants with higher SCS than lower SCS, in both devices (HVM 1 = 30.2, P < 0.001; HVM 2 = 9.7, P = 0.02). Pairwise comparisons showed that repeatability coefficients were significantly lower for Black or African American participants than White (mean SCS difference = 22.3, P = 0.001) and Asian participants (mean SCS difference = 23.7, P = 0.005) in one device (VM 1).
Conclusion And Implications:
Findings support using the average of the second and third scans as a more reliable method for assessing SCS. Reporting device-specific repeatability coefficients for the VM may enhance the interpretability of SCS, particularly for individuals with low SCS and for Black or African American participants.
