Bias in protein and potassium intake collected with 24-h recalls (EPIC-Soft) is rather comparable across European populations

Crispim, S.P.; Geelen, A.; Freisling, H.; Souverein, O.W.; Hulshof, P.J.M.; Ocke, M.C.; Boshuizen, H.C.; Andersen, L.F.; Ruprich, J.; Keizer, W. de; Huybrechts, I.; Lafay, L.; DeMagistris, M.S.; Ricceri, F.; Tumino, R.; Krogh, V.; Bueono-de-Mesquita, H.B.; Beulens, J.W.J.; Boutron-Ruault, M.C.; Naska, A.; Crowe, F.L.; Boeing, H.; McTaggart, A.R.; Kaaks, R.; Veer, P. van 't; Slimani, N.


Purpose: We investigated whether group-level bias of a 24-h recall estimate of protein and potassium intake, as compared to biomarkers, varied across European centers and whether this was influenced by characteristics of individuals or centers. Methods: The combined data from EFCOVAL and EPIC studies included 14 centers from 9 countries (n = 1,841). Dietary data were collected using a computerized 24-h recall (EPIC-Soft). Nitrogen and potassium in 24-h urine collections were used as reference method. Multilevel linear regression analysis was performed, including individual-level (e.g., BMI) and center-level (e.g., food pattern index) variables. Results: For protein intake, no between-center variation in bias was observed in men while it was 5.7% in women. For potassium intake, the between-center variation in bias was 8.9% in men and null in women. BMI was an important factor influencing the biases across centers (p <0.01 in all analyses). In addition, mode of administration (p = 0.06 in women) and day of the week (p = 0.03 in men and p = 0.06 in women) may have influenced the bias in protein intake across centers. After inclusion of these individual variables, between-center variation in bias in protein intake disappeared for women, whereas for potassium, it increased slightly in men (to 9.5%). Center-level variables did not influence the results. Conclusion: The results suggest that group-level bias in protein and potassium (for women) collected with 24-h recalls does not vary across centers and to a certain extent varies for potassium in men. BMI and study design aspects, rather than center-level characteristics, affected the biases across centers