|Title||A bivariate measurement error model for nitrogen and potassium intakes to evaluate the performance of regression calibration in the European Prospective Investigation into Cancer and Nutrition study.|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||Ferrari, P, Roddam, A, Fahey, MT, Jenab, M, Bamia, C, Ocké, M, Amiano, P, Hjartåker, A, Biessy, C, Rinaldi, S, Huybrechts, I, Tjønneland, A, Dethlefsen, C, Niravong, M, Clavel-Chapelon, F, Linseisen, J, Boeing, H, Oikonomou, E, Orfanos, P, Palli, D, M de Magistris, S, Bueno-de-Mesquita, HB, Peeters, PHM, Parr, CL, Braaten, T, Dorronsoro, M, Berenguer, T, Gullberg, B, Johansson, I, Welch, AA, Riboli, E, Bingham, S, Slimani, N|
|Journal||Eur J Clin Nutr|
|Volume||63 Suppl 4|
|Date Published||2009 Nov|
|Keywords||Adult, Aged, Calibration, Diet, Diet Records, Diet Surveys, Europe, Female, Humans, Linear Models, Logistic Models, Male, Micronutrients, Middle Aged, Nitrogen, Potassium, Prospective Studies, Reference Values, Reproducibility of Results|
OBJECTIVES: Within the European Prospective Investigation into Cancer and Nutrition (EPIC) study, the performance of 24-h dietary recall (24-HDR) measurements as reference measurements in a linear regression calibration model is evaluated critically at the individual (within-centre) and aggregate (between-centre) levels by using unbiased estimates of urinary measurements of nitrogen and potassium intakes.
METHODS: Between 1995 and 1999, 1072 study subjects (59% women) from 12 EPIC centres volunteered to collect 24-h urine samples. Log-transformed questionnaire, 24-HDR and urinary measurements of nitrogen and potassium intakes were analysed in a multivariate measurement error model to estimate the validity of coefficients and error correlations in self-reported dietary measurements. In parallel, correlations between means of 24-HDR and urinary measurements were computed. Linear regression calibration models were used to estimate the regression dilution (attenuation) factors.
RESULTS: After adjustment for sex, centre, age, body mass index and height, the validity coefficients for 24-HDRs were 0.285 (95% confidence interval: 0.194, 0.367) and 0.371 (0.291, 0.446) for nitrogen and potassium intakes, respectively. The attenuation factors estimated in a linear regression calibration model were 0.368 (0.228, 0.508) for nitrogen and 0.500 (0.361, 0.639) for potassium intakes; only the former was different from the estimate obtained using urinary measurements in the measurement error model. The aggregate-level correlation coefficients between means of urinary and 24-HDR measurements were 0.838 (0.637, 0.932) and 0.756 (0.481, 0.895) for nitrogen and potassium intakes, respectively.
CONCLUSIONS: This study suggests that 24-HDRs can be used as reference measurements at the individual and aggregate levels for potassium intake, whereas, for nitrogen intake, good performance is observed for between-centre calibration, but some limitations are apparent at the individual level.
|Alternate Journal||Eur J Clin Nutr|
|Grant List|| / / British Heart Foundation / United Kingdom |
/ / Cancer Research UK / United Kingdom
/ / Department of Health / United Kingdom
/ / Medical Research Council / United Kingdom
/ / Wellcome Trust / United Kingdom