Estimating the alcohol-breast cancer association: a comparison of diet diaries, FFQs and combined measurements.
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.
MRC Biostatistics Unit, Institute of Public Health, University Forvie Site, Robinson Way, Cambridge, UK. ruth.keogh@mrc-bsu.cam.ac.uk
Ruth H
RH
Keogh
Jin Young
JY
Park
Ian R
IR
White
Marleen A H
MA
Lentjes
Alison
A
McTaggart
Amit
A
Bhaniani
Benjamin J
BJ
Cairns
Timothy J
TJ
Key
Darren C
DC
Greenwood
Victoria J
VJ
Burley
Janet E
JE
Cade
Christina C
CC
Dahm
Gerda K
GK
Pot
Alison M
AM
Stephen
Gabriel
G
Masset
Eric J
EJ
Brunner
Kay-Tee
KT
Khaw
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000453:epidemiology*; D000434:Alcoholic Beverages / Q000706:statistics & numerical data*; D001943:Breast Neoplasms / Q000453:epidemiology*; D016022:Case-Control Studies; D015984:Causality; D015331:Cohort Studies; D015897:Comorbidity; D004032:Diet; D015930:Diet Records; D005260:Female; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult