Surrogate measures of dietary intake

In studying health and disease in elderly subjects, information may be needed concerning current or past dietary intake. Regardless of whether emphasis is placed on current or past intake, the validity of self-reported dietary information probably diminishes with increasing respondent age. In studying diet in elderly subjects, obtaining information from surrogate sources may improve data quality and provide information otherwise unavailable for decreased or incompetent subjects. This review addresses availability of data from surrogates, validity of surrogate responses, and methodological issues in analysis of surrogate data. This literature review documents that surrogate respondents can provide dietary information, but the data on elderly persons are extremely limited. The literature also indicates that surrogate dietary data may introduce misclassification in analytical investigations, but that surrogate data may be useful in descriptive studies. Methodological studies on surrogate reporting should facilitate research on diet and disease in elderly subjects.