Validation of protein and potassium intakes assessed from 24 h recalls against levels estimated from 24 h urine samples in children and adolescents of Turkish descent living in Germany: results from the EVET! Study.

Objective: Nutrition-related health problems such as obesity are frequent among children and adolescents of Turkish descent living in Germany, yet data on their dietary habits are scarce. One reason might be the lack of validated assessment tools for this target group. We therefore aimed to validate protein and K intakes from one 24 h recall against levels estimated from one 24 h urine sample in children and adolescents of Turkish descent living in Germany.

Design: Cross-sectional analyses comprised estimation of mean differences, Pearson correlation coefficients, cross-classifications and Bland-Altman plots to assess the agreement between the nutritional intake estimated from a single 24 h recall and a single 24 h urine sample collected on the previous day.

Setting: Dortmund, Germany.

Subjects: Data from forty-three study participants (aged 5-18 years; 26% overweight) with a traditional Turkish background were included.

Results: The 24 h recall significantly overestimated mean protein and K intake by 10·7 g/d (95% CI of mean difference: 0·6, 20·7 g/d) and 344 mg/d (95% CI 8, 680 mg/d), respectively. Correlations between intake estimates were r = 0·25 (P = 0·1) and 0·31 (P = 0·05). Both methods classified 70% and 69% of the participants into the same/adjacent quartile of protein and K intake and misclassified 7% and 7%, respectively, into the opposite quartile. Bland-Altman plots indicated a wide scattering of differences in both protein and K intake.

Conclusions: Among children and adolescents of traditional Turkish descent living in Germany, one 24 h recall may only be valid for categorizing subjects into high, medium or low consumers.