Reproducibility and validity of a quantitative FFQ designed for patients with type 2 diabetes mellitus from southern Brazil.

Objective To evaluate the reproducibility and validity of a previously constructed FFQ to assess the usual diet of patients with type 2 diabetes mellitus (T2DM). Design Cross-sectional survey using two quantitative FFQ (1-month interval) supported by a food photograph portfolio, a 3 d weighed diet record (WDR) and urinary N output measurement (as a biomarker of protein intake). Setting Group of Nutrition in Endocrinology, southern Brazil. Subjects Out-patients with T2DM. Results From a total of 104 eligible T2DM patients, eighty-eight were included in the evaluation of FFQ reproducibility and seventy-two provided data for the validity study. The intakes estimated from the two FFQ did not differ ( P > 0·05) and the correlation coefficients were significant ( P P Conclusions This quantitative FFQ was valid and precise to assess the usual diet of patients with T2DM, according to its validity and reproducibility.