Validation of a short food frequency questionnaire to evaluate nutritional lifestyles in hypercholesterolemic...

The purpose of our study was to develop and validate a short food frequency questionnaire which could assess the nutritional lifestyles of hypercholesterolemic patients consulting in daily practice.

The questionnaire explores 11 nutrient categories. Hundred and thirty-one patients were recruited for the construct validity and 58 patients for the external validity in La Pitié Hospital, Paris. The reference method used was the diet history. To measure the internal consistency and to test the sensibility to change on a large scale, the questionnaire was used in an observational study conducted in Spain in 1048 moderate hypercholesterolemic patients. Psychometric analyses included construct validity, internal consistency, test-retest reliability, external validity and sensibility to change.

Validation of the questionnaire indicated a good internal consistency (Cronbach Coefficient Alpha at 0.69) and test-retest reliability (intraclass correlation coefficient=0.89). The correlation between the scores of the FFQ and those of the diet history was significant with a Pearson correlation coefficient at 0.3 (P=0.029). The comparison between the ranking of the patients showed an agreement of 72% with a kappa of 0.48 [0.10; 0.69]. The sensibility to change was good with a score evolution improving one and four months after nutrition advices: 28.2% of patients ranked in group 1 at inclusion versus 61.3% (P<0.0001) at one month and 75.2% (P<0.0001) at four months.

In conclusion, we developed and validated a food questionnaire for hypercholesterolemic patients, which can be used as a therapeutic education tool in daily practice or in clinical research.