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June 20, 2001

Brassica Vegetables and Breast Cancer Risk—Reply

Author Affiliations

Stephen J.LurieMD, PhD, Senior EditorIndividualAuthorJody W.ZylkeMD, Contributing EditorIndividualAuthor

JAMA. 2001;285(23):2975-2977. doi:10.1001/jama.285.23.2975

In Reply: In the case-control study of 2832 cases by Dr Terry and colleagues, consumption of brassica vegetables was associated with a 25% reduction in breast cancer risk comparing the highest vs lowest quartile of intake. In our combined analysis of 7 cohort studies, including more than 7000 cases, in the Pooling Project of Prospective Studies of Diet and Cancer,1 the mean (SD) brassica vegetable intakes ranged from 11 (18) g/d for the Sweden Mammography Cohort (cabbage only) to 39 (24) g/d for the Netherlands Cohort Study. Brassica vegetable consumption was not associated with breast cancer risk when modeled as a continuous variable or as quartiles. For comparisons of the highest vs lowest quartile of intake, the study-specific multivariate RRs ranged from 0.79 (95% CI, 0.58-1.07) in the New York University Women's Health Study to 1.10 (95% CI, 0.95-1.28) in the Nurses' Health Study (b) (follow-up years, 1986-1996); the pooled multivariable RR was 0.97 (95% CI, 0.89-1.05; P = .30 for between studies for heterogeneity; P = .72 for trend). The results were similar when we adjusted for intakes of either total vegetables or nonbrassica vegetables.