A case-control study on the dietary intake of mushrooms and breast cancer risk among Korean women

To evaluate the association between dietary mushroom intake and breast cancer risk, a total of 362 women between the ages of 30 and 65 years who were histologically confirmed to have breast cancer were matched to controls by age (+/-2 years) and menopausal status. Mushroom intake was measured via a food frequency questionnaire that was administered by well-trained interviewers. The associations between the daily intake and the average consumption frequency of mushrooms with breast cancer risk were evaluated using matched data analysis. Both the daily intake (5th vs. 1st quintile, OR = 0.48, 95% CI = 0.30-0.78, p for trend 0.030) and the average consumption frequency of mushrooms (4th vs. 1st quartile, OR = 0.54, 95% CI = 0.35-0.82, p for trend 0.008) were inversely associated with breast cancer risk after adjustment for education, family history of breast cancer, regular exercise [>or=22.5 MET (metabolic equivalent)-hr/week], BMI (body mass index, Kg/m(2)), number of children and whether they are currently smoking, drinking or using multivitamin supplements. Further adjustments were made for energy-adjusted carbohydrate, soy protein, folate and vitamin E levels, which tended to attenuate these results. After a stratification was performed according to menopausal status, a strong inverse association was found in postmenopausal women (OR = 0.16, 95% CI = 0.04-0.54, p for trend = 0.0058 for daily intake; OR = 0.17, 95% CI = 0.05-0.54, p for trend = 0.0037 for average frequency), but not in premenopausal women. In conclusion, the consumption of dietary mushrooms may decrease breast cancer risk in postmenopausal women.