RECALL BIAS IN THE ASSOCIATION OF MICRONUTRIENT INTAKE AND BREAST-CANCER

A nested case-control study within the Canadian National Breast Screening Study was conducted to examine whether there was evidence for recall bias in the reporting of past micronutrient intake. Dietary data collected upon enrollment between 1982 and 1985 from 325 breast cancer cases and 628 matched controls were compared with data collected in 1988 after disease diagnosis. The retrospective estimates of mean micronutrient intakes from food sources were found to be very similar to the prospective estimates for cases and controls. Errors of omission and commission for the reporting of previous supplementary vitamin use were identical for both subject groups. The odds ratios estimated for the association of micronutrient intake and breast cancer for the prospective and retrospective data were similar in magnitude and the 95% confidence intervals overlapped considerably. There was no evidence for recall bias in the estimation of past micronutrient intake by breast cancer cases as compared to controls.