1. ¹Dipartimento di Medicina, Chirurgia e Odontoiatria, Università di Milano, Polo San Paolo, Milano, Italy
2. ²Istituto di Ricerche Farmacologiche 'Mario Negri', Milano, Italy
3. ³Dipartimento di Scienze Biomediche e Biotecnologia, Università di Brescia, Brescia, Italy
4. ⁴International Agency for Research on Cancer, Lyon Cedex, France
5. ⁵Centro di Riferimento Oncologico, Aviano (Pordenone), Italy
6. ⁶Istituto di Biometria e Statistica Medica, Università di Milano, Milano, Italy

Correspondence: A Tavani, Istituto di Ricerche Farmacologiche 'Mario Negri', Via Eritrea 62, 20157 Milan, Italy. E-mail: tavani@marionegri.it

Guarantor: A Tavani.

Contributors: CLV and SF conceived and coordinated the study. MF, EN and AD managed and analysed data. AT wrote the paper. MP gave valuable contribution on nutrition.

Received 26 March 2003; Revised 4 July 2003; Accepted 2 August 2003.

Abstract

Objective: The reproducibility and validity of coffee, decaffeinated coffee and tea intake has not been adequately studied, particularly in Italy, where coffee drinking is peculiar in terms of type and amount of coffee consumed.

Design: We compared coffee and tea consumption, measured by two interviewer-administered food frequency questionnaires (FFQ), with average intake derived from two 7-day dietary (DD) records (the reference method) on 395 volunteers. The Pearson correlation coefficients (r) were used to assess both reproducibility and validity of information on coffee intake.

Results: A satisfactory level of reproducibility and validity of the pattern consumption was observed for coffee, decaffeinated coffee and tea. The reproducibility for both sex combined showed r of 0.74–0.78 for coffee, 0.57–0.65 for decaffeinated coffee and 0.61–0.67 for tea. The validity was about 0.70 for coffee, around 0.58 for decaffeinated coffee and 0.56–0.60 for tea intake.

Conclusions: The FFQ is a satisfactorily reliable and valid instrument for collecting information on coffee, decaffeinated coffee and tea intake.

Sponsorship: Supported by the Italian Association for Research on Cancer, Milan, Italy, and by the Commission of the European Communities (Contract No.: QLKI-CT-2000-00069).