European Prospective Investigation into Cancer and Nutrition (EPIC) calibration study: rationale, design and population characteristics

• Published in: Public health nutrition Vol. 5; no. 6b; pp. 1125 - 1145
• Main Authors: Slimani, N, Kaaks, R, Ferrari, P, Casagrande, C, Clavel-Chapelon, F, Lotze, G, Kroke, A, Trichopoulos, D, Trichopoulou, A, Lauria, C, Bellegotti, M, Ocké, MC, Peeters, PHM, Engeset, D, Lund, E, Agudo, A, Larrañaga, N, Mattisson, I, Andren, C, Johansson, I, Davey, G, Welch, AA, Overvad, K, Tjønneland, A, van Staveren, WA, Saracci, R, Riboli, E
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01-12-2002
• Subjects: 24-hour dietary recall; Adult; Aged; Annan klinisk medicin; Calibration; Cancer; Chronic illnesses; Clinical Medicine; Design; Diet; Diet Surveys; dietary-intake measurements; Disease; EPIC study; Epidemiology; Europe; Feeding Behavior; Female; food; Humans; Klinisk medicin; Lifestyles; Male; measurement error; Medical and Health Sciences; Medical research; Medicin och hälsovetenskap; Medicine; Mental Recall; Middle Aged; multicenter cohort; Neoplasms - etiology; Nutrition research; Nutritional Physiological Phenomena; Other Clinical Medicine; Population characteristics; Population Surveillance - methods; Prospective Studies; Public health; questionnaire; Questionnaires; relative risk; Research Design; Risk Factors; Smoking - adverse effects; study design; validity; Greece; Sweden; Netherlands; United Kingdom > UK; Norway; Denmark; Italy; France; Germany; Spain; Study design; 24-Hour dietary recall; Calibration; EPIC study; Europe
• ISSN: 1368-9800; 1475-2727; 1475-2727
• DOI: 10.1079/PHN2002395

The European Prospective Investigation into Cancer and Nutrition (EPIC), which covers a large cohort of half a million men and women from 23 European centres in 10 Western European countries, was designed to study the relationship between diet and the risk of chronic diseases, particularly cancer. Information on usual individual dietary intake was assessed using different validated dietary assessment methods across participating countries. In order to adjust for possible systematic over- or underestimation in dietary intake measurements and correct for attenuation bias in relative risk estimates, a calibration approach was developed. This approach involved an additional dietary assessment common across study populations to re-express individual dietary intakes according to the same reference scale. A single 24-hour diet recall was therefore collected, as the EPIC reference calibration method, from a stratified random sample of 36 900 subjects from the entire EPIC cohort, using a software program (EPIC-SOFT) specifically designed to standardise the dietary measurements across study populations. This paper describes the design and populations of the calibration sub-studies set up in the EPIC centres. In addition, to assess whether the calibration sub-samples were representative of the entire group of EPIC cohorts, a series of subjects’ characteristics known possibly to influence dietary intakes was compared in both population groups. This was the first time that calibration sub-studies had been set up in a large multi-centre European study. These studies showed that, despite certain inherent methodological and logistic constraints, a study design such as this one works relatively well in practice. The average response in the calibration study was 78.3% and ranged from 46.5% to 92.5%. The calibration population differed slightly from the overall cohort but the differences were small for most characteristics and centres. The overall results suggest that, after adjustment for age, dietary intakes estimated from calibration samples can reasonably be interpreted as representative of the main cohorts in most of the EPIC centres.