Relative validation of 24-h urinary XXXX excretion as a biomarker for dietary @entity3096 intake from fruit and vegetables in healthy adolescents.

@entity3088 @entity3096 @entity35620 @entity102
PURPOSE: A biomarker for dietary @entity3096 intake from fruit and vegetables (FlavFV) is needed to elucidate the relevance of @entity3088 from these sources for the prevention of @entity102 . Urinary @entity35620 (HA)-a major metabolite of @entity3088 -is promising in this respect as it was shown to satisfyingly indicate fruit and vegetable consumption in different age groups. Therefore, we validated urinary HA as a biomarker for intake of FlavFV. METHODS: Analyses included data from 287 healthy adolescents of the DONALD Study (aged 9-16  years) for whom a minimum of two pairs of HA measurements from 24-h urine samples (test method) and FlavFV intake estimated from 3-day weighed dietary records (reference method) existed. Agreement between both methods was assessed by Spearman correlation and cross-classification analyses. Possible confounders of the association were identified by linear regression models. Analyses were performed using a split-sample approach allowing for consecutive exploration (n  =  192) and confirmation (n  =  95) of results. RESULTS: Agreement between urinary HA excretion and FlavFV intake was moderate according to correlation analysis in the exploratory sample (r unadjusted  =  0.47, P  <  0.0001). Yet, 79  % of the subjects were classified into same/adjacent quartiles, and only 5  % were misclassified into opposite quartiles. These findings were corroborated by analyses in the confirmatory sample (r unadjusted  =  0.64; 88  % in same/adjacent vs. 4  % in opposite quartiles). Body surface area (BSA) was the only relevant covariate in the exploratory sample, and its adjustment improved cross-classification estimates in both subsamples. CONCLUSIONS: BSA-adjusted 24-h urinary HA excretion represents a suitable biomarker of habitual FlavFV intake in healthy adolescents.
