Validation Studies of Diets of Children and Adolescents

Abstract

Burrows and colleagues (1Burrows T.L. Martin R.J. Collins C.E. A systematic review of the validity of dietary assessment methods in children when compared with the method of doubly labeled water.J Am Diet Assoc. 2010; 110: 1501-1510Google Scholar) reviewed 15 studies that compared energy intake calculated from various dietary assessment methods to energy expenditure estimated using doubly labeled water. Burrows and colleagues identified dietary assessment methods that appear most accurate for children and adolescents of certain ages, and recommended further research. In the interim, their conclusions should not be construed as recommendations. Moreover, the strategy and emphases of further research must be specifically focused. First, conclusions that methods are “most accurate” or provide “better estimates” were based on failures by original investigators to find statistically significant differences between assessed energy intake and estimated energy expenditure (2Johnson R.K. Driscoll P. Goran M.I. Comparison of multiple-pass 24-hour recall estimates of energy intake with total energy expenditure determined by the doubly labeled water method in young children.J Am Diet Assoc. 1996; 96: 1140-1144Google Scholar, 3Lindquist C.H. Cummings T. Goran M.I. Use of tape-recorded food records in assessing children's dietary intake.Obes Res. 2000; 8: 2-11Google Scholar, 4Sjöberg A. Slinde F. Arvidsson D. Ellegård L. Gramatkovski E. Hallberg L. Hulthén L. Energy intake in Swedish adolescents: validation of diet history with doubly labelled water.Eur J Clin Nutr. 2003; 57: 1643-1652Google Scholar, 5Livingstone M.B.E. Prentice A.M. Coward W.A. Strain J.J. Black A.E. Davies P.S.W. Stewart C.M. McKenna P.G. Whitehead R.G. Validation of estimates of energy intake by weighed dietary record and diet history in children and adolescents.Am J Clin Nutr. 1992; 56: 29-35Google Scholar, 6O'Connor J. Ball E.J. Steinbeck K.S. Davies P.S.W. Wishart C. Gaskin K.J. Baur L.A. Comparison of total energy expenditure and energy intake in children aged 6-9 y.Am J Clin Nutr. 2001; 74: 643-649Google Scholar, 7Lanigan J.A. Wells J.C.K. Lawson M.S. Lucas A. Validation of food diary method for assessment of dietary energy and macronutrient intake in infants and children aged 6-24 months.Eur J Clin Nutr. 2001; 55: 124-129Google Scholar, 8Davies P.S.W. Coward W.A. Gregory J. White A. Mills A. Total energy expenditure and energy intake in the pre-school child: a comparison.Br J Nutr. 1994; 72: 13-20Google Scholar); of these, only one (2Johnson R.K. Driscoll P. Goran M.I. Comparison of multiple-pass 24-hour recall estimates of energy intake with total energy expenditure determined by the doubly labeled water method in young children.J Am Diet Assoc. 1996; 96: 1140-1144Google Scholar) addressed either the size of a meaningful difference or the power of the study to detect such a difference. Whether two energy estimates are statistically equivalent may be ascertained (9Tryon W.W. Lewis C. An inferential confidence interval method of establishing statistical equivalence that corrects Tryon's (2001) reduction factor.Psychol Methods. 2008; 13: 272-277Google Scholar, 10Schuirmann D.J. A comparison of the two one-sided tests procedure and the power approach for assessing the equivalence of average bioavailability.J Pharmacokinet Biopharm. 1987; 15: 657-680Google Scholar), but in no reviewed study was the sample size sufficient to permit such ascertainment using a meaningful equivalence criterion. Although some investigators and Burrows and colleagues mentioned small samples as a limitation, the sample sizes required to investigate equivalence may be unappreciated (11Smith A.F. Baxter S.D. Hardin J.W. Guinn C.H. Royer J.A. Litaker M.S. Validation-study conclusions from dietary reports by fourth-grade children observed eating school meals are generalisable to dietary reports by comparable children not observed.Public Health Nutr. 2007; 10: 1057-1066Google Scholar). Second, although Burrows and colleagues noted that participation in a validation study may influence reported energy intake, they did not emphasize that researchers should assess the effect of participation (11Smith A.F. Baxter S.D. Hardin J.W. Guinn C.H. Royer J.A. Litaker M.S. Validation-study conclusions from dietary reports by fourth-grade children observed eating school meals are generalisable to dietary reports by comparable children not observed.Public Health Nutr. 2007; 10: 1057-1066Google Scholar, 12Baxter S.D. Hardin J.W. Smith A.F. Royer J.A. Guinn C.H. Mackelprang A.J. Twenty-four hour dietary recalls by fourth-grade children were not influenced by observations of school meals.J Clin Epidemiol. 2009; 62: 878-885Google Scholar, 13Smith A.F. Concerning the suitability of recordkeeping for validating and generalizing about reports of health-related information.Rev Gen Psychol. 1999; 3: 133-150Google Scholar). No reviewed study investigated the impact of participation on assessed energy intake. Third, investigation of unstandardized dietary assessment methods seems ill advised. From studies that used very different diet history methods, but without discussing these differences, Burrows and colleagues concluded that the diet history provided “better estimates for adolescents aged ≥16 years” (1Burrows T.L. Martin R.J. Collins C.E. A systematic review of the validity of dietary assessment methods in children when compared with the method of doubly labeled water.J Am Diet Assoc. 2010; 110: 1501-1510Google Scholar). One diet history (5Livingstone M.B.E. Prentice A.M. Coward W.A. Strain J.J. Black A.E. Davies P.S.W. Stewart C.M. McKenna P.G. Whitehead R.G. Validation of estimates of energy intake by weighed dietary record and diet history in children and adolescents.Am J Clin Nutr. 1992; 56: 29-35Google Scholar) was seemingly an ad hoc collaboration between the respondent, a parent, and other individuals and information sources, and concerned “usual intake” and intake during 2 specific weeks; the other (4Sjöberg A. Slinde F. Arvidsson D. Ellegård L. Gramatkovski E. Hallberg L. Hulthén L. Energy intake in Swedish adolescents: validation of diet history with doubly labelled water.Eur J Clin Nutr. 2003; 57: 1643-1652Google Scholar) was a respondent-completed questionnaire about habitual intake and an interview. Single-interviewer studies, as these were, with procedural details at the discretion of the interviewer, are problematic for inference. Burrows and colleagues did not discuss these limitations. Fourth, dietary assessment validation research must be concerned not only with energy, but with foods (14Smith A.F. Baxter S.D. Hardin J.W. Nichols M.D. Conventional analyses of data from dietary validation studies may misestimate reporting accuracy: illustration from a study of the effect of interview modality on children's reporting accuracy.Public Health Nutr. 2007; 10: 1247-1256Google Scholar). For this, understanding relevant psychological processes is required. For example, recent research on free recall has shown that the probability that a reported item is correct declines over reported items, and that recall frequently terminates with an error (15Unsworth N. Brewer G.A. Spillers G.J. Understanding the dynamics of correct and error responses in free recall: Evidence from externalized free recall.Memory Cogn. 2010; 38: 419-430Google Scholar). Responses to probes in dietary assessment methods raise estimated energy intake but may be intrusions. Concerning this, doubly labeled water is uninformative, a limitation not mentioned by Burrows and colleagues. In contrast, direct observation, dismissed by Burrows and colleagues as sharing limitations with methods it is used to validate, is useful (16Baxter S.D. Guinn C.H. Royer J.A. Hardin J.W. Smith A.F. Shortening the retention interval of 24-hour dietary recalls increases fourth-grade children's accuracy for reporting energy and macronutrient intake at school meals.J Am Diet Assoc. 2010; 110: 1178-1188Google Scholar). Further, the criticism that a method “relies on memory” is unhelpful. Although veridical recollection is not always possible, memory is functional, and substantial research shows that its operation is lawful. Dietary assessment methods researchers must appreciate the operational principles and particular limitations of memory to maximally exploit its functionality. These issues deserve attention as additional dietary assessment methods research, including research with doubly labeled water, is conducted. Work prepared during a sabbatical visit at the Institute for Information Processing and Decision Making, University of Haifa, Haifa, Israel. A Systematic Review of the Validity of Dietary Assessment Methods in Children when Compared with the Method of Doubly Labeled WaterJournal of the American Dietetic AssociationVol. 110Issue 10PreviewMeasuring dietary intake in children enables the assessment of nutritional adequacy of individuals and groups and can provide information about nutrients, including energy, food, and eating habits. The aim of this review was to determine which dietary assessment method(s) provide a valid and accurate estimate of energy intake by comparison with the gold standard measure, doubly labeled water (DLW). English-language articles published between 1973 and 2009 and available from common nutrition databases were retrieved. Full-Text PDF Authors' ResponseJournal of the American Dietetic AssociationVol. 111Issue 8PreviewThank you for the opportunity to respond to Smith's letter regarding our article in the October 2010 issue of the Journal (1). Full-Text PDF