Psychometric properties of the healthful eating belief scales for persons at risk of diabetes.

OBJECTIVE To examine the validity and reliability of Theory of Planned Behavior (TPB) scales for healthful eating for persons at risk for diabetes. DESIGN Cross-sectional, using a self-administered questionnaire. SETTING Community in the Midwest. PARTICIPANTS 106 adults who self-identified based on one or more American Diabetes Association diabetes risks. VARIABLES MEASURED Behavioral, normative, and control beliefs; and attitude, subjective norm, perceived behavioral control, and intention to eat a healthful diet. ANALYSIS Construct validity was assessed with factor analyses and measurement and structural models using structural equation modeling. Reliability of the scales was assessed with Cronbach alpha and a 2-month test-retest. RESULTS Factor analysis loadings were greater than .37. Cronbach alphas for the behavioral, normative, and control belief scales were .80, .91, and .84, respectively. The measurement model revealed that the measures were significant estimates for the TPB constructs, and they fit well as indirect measures of attitude, subjective norm, and perceived behavioral control in predicting intention to eat a healthful diet. Test-retest revealed 2-month stability of the scales. CONCLUSIONS AND IMPLICATIONS Scales for measuring TPB behavioral, normative, and control beliefs were valid and reliable for use with adults at risk for diabetes. Further examination with minority persons is warranted.