RELIABILITY AND COMPARABILITY OF 3 DIETARY ASSESSMENT METHODS FOR ESTIMATING FRUIT AND VEGETABLE INTAKES

Although fruits and vegetables have been evaluated in numerous epidemi ologic studies, few validation studies have examined fruits and vegeta bles. We examined the reproducibility and comparability of fruit and v egetable intakes estimated by diet records, food frequency questionnai res, and modules (brief food frequency questionnaires) in 101 control participants of a I-year diet intervention trial. For each method, mea n intakes at baseline and 3 months were generally within 0.3 serving p er day for juice, fruits, vegetables, and total fruits and vegetables. In addition, Pearson correlations for the two time periods generally exceeded 0.55 for these four groups for each method. We evaluated comp arability of intakes for 15 days of diet records, 1-year food frequenc y questionnaires, and modules, respectively. Mean total fruit and vege table intakes were 6.3, 6.5, and 3.8 servings per day for diet records , food frequency questionnaires, and modules. For each pair wise combi nation of methods, Pearson correlations exceeded 0.45 for juice, fruit s, and total fruits and vegetables; correlations were lower for vegeta bles. Exact agreement in quintile assignment was less than 45%, howeve r. These results indicate that estimates of fruit and vegetable intake s and disease associations may differ depending on the method used to assess fruit and vegetable intake.