Validity and Reliability of a Dietary Assessment Method: The Application of a Digital Camera with a Mobile Phone Card Attachment

Abstract

SummaryThis study was aimed at evaluation of the validity and reliability of an alter native dietary measurement method that assists epidemiologic studies. We validated a handheld personal digital assistant with camera and mobile phone card, called Wellnavi, in which a 1-d weighed diet record was employed as a reference method. Twenty college stu dents majoring in food and nutrition participated in this study. They were asked to keep a diet record and to take digital photos of all these recorded food at the same time, then send them to the dietitians by the mobile phone card. In the reliability study, other twenty stu dents from the same college were asked to take digital photos of the same meal during a day by two same instruments under the same circumstances and to send these photos to the dif ferent dietitians electronically. With respect to validity, median nutrient intakes estimated by the Wellnavi method and the diet record method are comparable. Correlation coefficients between the median nutrient intakes estimated from these two methods ranged from 0.46 for monounsaturated fatty acid to 0.93 for vitamin B12 and copper (median r=0.77). With respect to reliability, our data show a good agreement between two Wellnavi instruments for most of the nutrients. Correlation coefficients between the nutrient intakes estimated from 2 instruments ranged from 0.55 for vitamin B1 and water-insoluble dietary fiber to 0.92 for vitamin B12 (median r=0.78). In conclusion, the results indicate this dietary assessment in strument can usefully measure individual dietary intakes for a variety of nutrients in an epi demiologic study. Key Words validity, reliability, dietary assessment, mobile phone card Recently, the relation between daily dietary intake and lifestyle-related disorders is receiving increasing at tention from both health professionals and the general public. National Health Promotion Movement in the 21st Century in Japan lays strong emphasis on increase of vegetable/fruit consumption and on intake of bal anced diet. This health promotion movement raises concerns about the needs of monitoring usual food con sumption patterns of target population. Several dietary assessment methods, for example, 24-h dietary recall, diet record and food frequency questionnaire (FFQ), are widely used to the collection of dietary information in the epidemiologic researches. Twenty-four-hour recall method is relatively simple, the results, however, greatly depends upon the respondents' memory and the trained interviewer; the diet record method is regarded providing most accurate dietary information but quite time consuming and burdensome to the participants; the FFQ method is easier for participants and inexpen sive, nevertheless, it is unable to supply precise informa tion of diet intake (1). Furthermore, currently available dietary assessment methods are rarely employed to col lect continuous dietary data of target population over multiweek time span, they unlikely reveal usual diet of the individuals (2-4). Therefore, a simpler an...

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