Comparison of an Electronic Food Diary with a Nonquantitative Food Frequency Questionnaire in Male and Female Smokers and Nonsmokers

Abstract

Food frequency questionnaires (FFQs) are the preferred method in epidemiologic studies, as they can be administered easily to large population samples at relatively low costs ( (1) Pietinen P. Hartman A.M. Haapa E. Rasanen L. et al. Reproducibility and validity of dietary assessment instruments II. a qualitative food frequency questionnaire. Am J Epidemiol. 1988; 128: 655-666 Google Scholar , (2) Axelson J.M. Csernus M.M. Reliability and validity of a food frequency checklist. J Am Diet Assoc. 1983; 83: 152-155 Google Scholar ). Problems may arise, however, from reporting or transcription errors. Increased variance results, which necessitates longer observation periods and larger numbers of subjects. When short-term effects of interventions or behavioral changes on current dietary intakes are of interest, food diaries appear to be the appropriate method. In addition, depending on the nature of the intervention, these studies are often limited in terms of the length of the observation period and the number of subjects participating. For example, the longer the period of abstinence from transient smoking, the fewer the number of smokers who will be able to pass this period successfully without relapse.