1. ¹Department of Food and Nutrition, Umeå University, Umeå, Sweden
2. ²Department of Human Biology, Maastricht University, Maastricht, The Netherlands
3. ³Department of Medicine, Visby Hospital, Visby, Sweden

Correspondence: L Hagfors, Department of Food and Nutrition, Umeå University, SE-901 87 Umeå, Sweden. E-mail: linda.hagfors@kost.umu.se

Received 4 September 2003; Revised 26 July 2004; Accepted 30 August 2004; Published online 13 October 2004.

Abstract

Objectives: The aim of the study was to validate a diet history interview (DHI) method and a 3-day activity registration (AR) with biological markers.

Subjects and study design: The reported dietary intake of 33 rheumatoid arthritis patients (17 patients on a Mediterranean-type diet and 16 patients on a control diet) participating in a dietary intervention study was assessed using the DHI method. The total energy expenditure (TEE), estimated by a 3-day AR, was used to validate the energy intake (EI). For nine subjects the activity registration was also validated by means of the doubly labelled water (DLW) method. The excretion of nitrogen, sodium and potassium in 24-h urine samples was used to validate the intake of protein, sodium and potassium.

Results: There was no significant difference between the EI and the TEE estimated by the activity registration or between the intake of protein, sodium and potassium and their respective biological markers. However, in general, the AR underestimated the TEE compared to the DLW method. No significant differences were found between the subjects in the Mediterranean diet group and the control diet group regarding the relationship between the reported intakes and the biological markers.

Conclusion: The DHI could capture the dietary intake fairly well, and the dietary assessment was not biased by the dietary intervention. The AR showed a bias towards underestimation when compared to the DLW method. This illustrates the importance of valid biological markers.

Sponsorship: The Faculty of Social Sciences, Umeå University; the Swedish Foundation for Health Care Sciences and Allergy Research; the Health Research Council in the Southeast of Sweden; the Swedish Rheumatism Association; the Swedish Nutrition Foundation; the JC Kempe Memorial Scholarship Fund; the 'Borgerskapet i Umeå' Fund, the 'Uppsala Hemsysterskola' Fund; Karlshamns AB; Nestlé Sweden AB; Van den Bergh Foods AB.