Validation of a food habits questionnaire: poor performance in male manual laborers.

OBJECT

To examine the reliability and validity of a food habits questionnaire developed by Kristal et al in male manual laborers.

DESIGN

A cross-sectional baseline survey.

SETTING

The community of Ottawa-Carleton, Canada.

SUBJECTS

All people working in non-office-based positions for two local governments were invited to a heart-health screening clinic. Male subjects (n = 362) who met risk factor eligibility criteria were interviewed and entered into the study.

MAIN OUTCOME MEASURES

The food habits questionnaire developed by Kristal et al was the main focus of analysis. Additional outcomes included a food frequency questionnaire and risk factors for cardiovascular disease.

STATISTICAL ANALYSES

Reliability was assessed using Cronbach's alpha and Pearson correlation coefficients; confirmatory factor analysis was also done. Validity assessment included partial correlations.

RESULTS

Low internal consistency was found for the five subscales of the questionnaire (alpha = .13 to .53). Confirmatory factor analysis did not reveal the postulated five-factor (subscale) structure. Correlation of the subscale scores with dietary fat intake was low (r = -.09 to -.23), and none of these associations were statistically significant after adjustment for age, body mass index, and education. An alternative scoring system that treated the questionnaire as a unidimensional behavioral checklist produced a higher internal consistency (alpha = .70) and significant correlation with dietary fat intake (r = -.27).

CONCLUSIONS

The psychometric properties and scoring of the food habits questionnaire need to be explored in additional populations before the questionnaire is adopted for general use.