Applying the triads method in the validation of dietary intake using biomarkers

Abstract

The triads method is applied in validation studies of dietary intake to evaluate the correlation between three measurements (food frequency questionnaire, reference method and biomarker) and the true intake using validity coefficients (ρ) IntroductionThe food frequency questionnaire (FFQ) is the most widely used instrument for the assessment of habitual food intake of a population. A properly validated FFQ for the intended population allows for stratification according to nutritional intake at the reference time considered 1 . Biomarkers offer the possibility of further validation aiming to improve the accuracy of the instrument 2 .In the process of validating a FFQ, multiple dietary records or 24-hour recalls (24hR) are often used as the method of reference 3 . The application of a reference method is important in order to estimate the errors associated with the FFQ, particularly the attenuation bias caused by random measurement errors of the instrument which will impact in the statistical power of the study 1,3 . The limitations of using dietary measures as the reference method is that both the instrument being tested (FFQ) and the reference method (24hR) are subject to the same random and systematic errors, because they rely on the memory of the interviewee and due to errors related to the estimation of the reported food intake 4,5 .In this scenario, biological markers may offer advantages and be able to improve the estimates of dietary intake assessment, due to the independence of their random errors in relation to the errors inherent to the intake questionnaires 5 . However, the biomarkers do not replace the tradition-REVISÃO REVIEW Yokota RTC et al. 2028 Cad. Saúde Pública, Rio de Janeiro, 26(11

Validation of a FFQ for estimating ω-3, ω-6 and trans fatty acid intake during pregnancy using mature breast milk and food recalls

“…Weak validation coefficients were found for total n-3 fatty acids, ARA and trans fatty acids for all tested methods. The Heywood case (validity coefficient X1) was verified for LN, total o-3 fatty acids, ARA and trans fatty acid intake 13 ( Table 4). Table 5 depicts the joint classification between self-reported o-3, o-6 and trans fatty acids by food recalls and FFQ, and mature breast milk composition.…”

“…12 Moreover, this technique could be applied to test the sensitivity of new biomarkers. 13 Previous studies employing triangulation to evaluate the performance of FFQ for estimating fatty acid intake in nonpregnant adults have reported satisfactory validity coefficients when considering adipose tissue, 14,15 plasma phospholipid 16 and erythrocyte membrane 17 as biochemical markers of o-3 and o-6 fatty acids.…”

“…Another limitation is that the dietary methods applied might have correlated errors, Validation of a FFQ for pregnant women DS Sartorelli et al which could explain the Heywood case 13 observed upon evaluating certain fatty acids. Finally, the main limitation was the small sample size.…”

Validation of a Self-report Tool to Measure Self-study in Medical School – Applying the Triads Method

“…This result may have occurred because FR and AR were recorded at the same time, and we cannot disregard the potential for correlated errors. Like other studies, we considered the upper limits of the true validity coefficient, while, the sample correlations between WR and FR and between WR and AR are the lower limits (Ocke & Kaaks, 1997;Yokota, Miyazaki, & Ito, 2010). Interpreted this way, a single self-reported measure appears to reflect self-study hours with reasonable accuracy, with the lowest validity coefficient ranging from 0.75 to 0.87 (ρART).…”

Reproducibility and validity of a quantitative FFQ designed for patients with type 2 diabetes mellitus from southern Brazil

“…In this sense, the method of triads is a technique that has been used in studies to validate dietary nutrient intakes (48)(49)(50) . This method adds a third variable -a biomarker -with an error independent from that of the FFQ and the reference method (3 d WDR) to assess the performance to estimate the true (but unknown) intake by calculating the validity coefficient (r) (51) . In fact, biomarkers should be used as additional measures because not all nutrients have biological markers and many are influenced by factors other than intake, such as bioavailability, metabolism and genetic factors (3) .…”