Agreement between Dietary Intake of Older Adults and Proxy Respondents Assessed by a Food Frequency Questionnaire

To evaluate the degree of agreement of dietary intake reported by the patient subject with the dietary intake reported by a respondent (a next-of-kin or a caregiver), collected by a validated Food Frequency Questionnaire (FFQ).

126 adults, both sexes, the average age was 65.9 years for patients and 54.4 years for respondents. They were recruited from the General Practice Clinic at the Clinical Hospital of São Paulo (AGD-FMUSP). The agreement between the responses given by patients and respondents was assessed using Spearman, weighted Kappa and Bland Altman tests.

The analysis for accuracy between responses (Spearman test) showed a moderate degree of agreement (0.31-0.39) for Energy, Total fat, Total Saturated Fatty Acids (SFA), Total Monounsaturated Fatty Acids (MUFA). Regarding food groups a moderate agreement was found for the majority of the foods (fruits (0.30), dairy products (0.50), natural juices (0.45), beans (0.48), butter/margarine (0.55), coffee (0.41) and soda (0.45), with the exception of vegetables (0.12) and rice (0.63). The ingestion differences did not exceeded the limit of the two standard deviations for the majority of the pairs (Bland Altman). A respondent subsample composed only of husband/wives (N = 36) revealed a moderate agreement concordance for most macronutrients studied (0.30 - 0.58), except polyunsaturated fats (0.25).

The results of this study show that, the FFQ may be used in cases where is impossible to get the answers directly from the patients.