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Title: Estimating the alcohol-breast cancer association: a comparison of diet diaries, FFQs and combined measurements

Authors: R.H. Keogh, J.Y. Park, I.R. White, M.A.H. Lentjes, A. McTaggart, A. Bhaniani, B.J. Cairns, T.J. Key, D.C. Greenwood, V.J. Burley, J.E. Cade, C.C. Dahm, G.K. Pot, A.M. Stephen, G. Masset, E.J. Brunner and K.-T. Khaw

Reference: European Journal of Epidemiology 27(7):547-559.

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Abstract:

The alcohol–breast cancer association has been established using alcohol intake measurements from Food Frequency Questionnaires (FFQ). For some nutrients diet diary measurements are more highly correlated with true intake compared with FFQ measurements, but it is unknown whether this is true for alcohol. A case–control study (656 breast cancer cases, 1905 matched controls) was sampled from four cohorts in the UK Dietary Cohort Consortium. Alcohol intake was measured prospectively using FFQs and 4- or 7-day diet diaries. Both relied on fixed portion sizes allocated to given beverage types, but those used to obtain FFQ measurements were lower. FFQ measurements were therefore on average lower and to enable fair comparison the FFQ was “calibrated” using diet diary portion sizes. Diet diaries gave more zero measurements, demonstrating the challenge of distinguishing never-from episodic-consumers using short term instruments. To use all information, two combined measurements were calculated. The first is an average of the two measurements with special treatment of zeros. The second is the expected true intake given both measurements, calculated using a measurement error model. After confounder adjustment the odds ratio (OR) per 10 g/day of alcohol intake was 1.05 (95 % CI 0.98, 1.13) using diet diaries, and 1.13 (1.02, 1.24) using FFQs. The calibrated FFQ measurement and combined measurements 1 and 2 gave ORs 1.10 (1.03, 1.18), 1.09 (1.01, 1.18), 1.09 (0.99,1.20), respectively. The association was modified by HRT use, being stronger among users versus non-users. In summary, using an alcohol measurement from a diet diary at one time point gave attenuated associations compared with FFQ.

Keywords. Breast cancer, Alcohol, Food frequency questionnaire, Diet diary, Case–control study, Measurement error

Acknowledgements.Professor Sheila Rodwell (known professionally as Sheila Bingham) who died in 2009 established the UK Dietary Cohort Consortium as part of the MRC Centre for Nutritional Epidemiology and Cancer of which she was Director. Ruth Keogh and Ian White were supported by the Medical Research Council [Unit Programme number U105260558]. The Medical Research Council also funds the UK Dietary Cohort Consortium at the MRC Centre for Nutritional Epidemiology in Cancer Prevention and Survival. The cohort studies included in this consortium received funding from: British Heart Foundation; Cancer Research UK; Department of Health, UK; Food Standards Agency, UK; Medical Research Council, UK; the Stroke Association, UK, and the World Cancer Research Fund.


© 2002-2010 Benjamin J. Cairns: e-mail ; ph +44 1865 289673 ;
Cancer Epidemiology Unit, University of Oxford, Richard Doll Building, Roosevelt Drive, Oxford OX3 7LF, U.K.