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Development of a tool to assess psychosocial indicators of fruit and vegetable intake for 2 federal programs
Marilyn S Townsend1, Lucia L Kaiser
1Department of Nutrition, University of California, Davis 95616-8669, USA. mstownsend@ucdavis.edu
Objective:
Development of an evaluation tool of psychosocial constructs for use by participants in 2 federal programs, Food Stamp Nutrition Education and the Expanded Food and Nutrition Education Program.
Design:
Cross-sectional data from a longitudinal study.
Participants:
Limited-resource women (n = 111) living in low-income communities.
Measures:
Test-retest reliability, internal consistency, ethnic differences, convergent validity.
Analysis:
Spearman rank order correlation, analysis of variance, principal components analysis.
Results:
Reliability coefficients ranged from a low of r = .18 (not significant) to r = .74 (P < .0001). Two items were deleted for not meeting criteria for reliability and 2 for redundancy. Ethnic differences at baseline were significant for 1 item. Domain constructs loaded on 4 to 5 factors for the biopsychosocial framework. Estimates of convergent validity of 9 constructs led to the deletion of 3 (ie, perceived barriers, social support, and perceived norms), with retention of perceived benefits, perceived control, self-efficacy, readiness to eat more fruit, readiness to eat more vegetables, and perceived diet quality. As an estimate of convergent validity, the final version of the tool with 6 constructs remaining showed significant correlations with indicators of diet quality: serum carotenoid values (r = .38, P < .001); hypothesized nutrients calculated from the mean of 3 24-hour dietary recalls (vitamin C, r = .47, P < .0001; vitamin A, r = .39, P < .0001; folate, r = .37, P < .0001; beta-carotene, r =.31, P < .001; and fiber, r = .46, P < .0001); fruit and vegetable servings (r = 0.55, P < .0001); Healthy Eating Index (r = .27, P < .05); and a fruit and vegetable behavioral scale (r = .60, P < .0001).
Conclusion And Implications:
This systematic process yielded a fruit and vegetable evaluation tool useful for practitioners and researchers. This is the first validation study of this type to estimate convergent validity with 5 indicators of diet quality, including a biomarker.
