Abstract
Objective: An algorithm for assessing changes in vegetable intake behavior was evaluated by assessing the relationship between habitual vegetable intake and cognitive factors.
Methods: In September 2009, a self-administered questionnaire was completed by male Japanese employees, aged 20~59 years, working at 20 sites with cafeterias in Niigata City in Japan. Vegetable intake was measured with a brief-type self-administered diet history questionnaire. Cognitive factors were measured using knowledge and self-efficacy scales. Stages of change were measured using a 2-item algorithm that assessed implementation of the target behavior and readiness to change. Associations between each of the above variables were also assessed.
Results: The distribution of the stages of change in 521 participants (median age, 42 years) was as follows: precontemplation (58.5%), contemplation (20.7%), preparation (13.8%), and action and maintenance (6.7%). Stages of change correlated with age (p = 0.028), but there was no significant correlation between the stages and BMI. Median vegetable intake per 1,000 kcal was 88.2 g in the precontemplation stage, 78.4 g in the contemplation stage, 98.9 g in the preparation stage, and 116.8 g in the action and maintenance stage. Significant differences were observed between each stage after adjustment for age (p = 0.004). Cognitive variables displayed the same tendency. In addition, strong positive correlations were found between the number of servings of vegetables during the day and vegetable intake.
Conclusions: The algorithm, developed to assess the stages of change, indicated clear correlations between vegetable intake and cognitive factors. We suggest that this algorithm can be used as an index for evaluating populations. However, when used with individuals, attention should be paid to possible stage misclassifications.
