Background:
Diet could be a major modifiable risk factor for breast cancer prevention.
Aim:
To assess the association between different food items and breast cancer risk among women in two tertiary care hospitals in Karachi, Pakistan.
Methods:
Between January 2009 and December 2010, 297 cases of histologically confirmed breast cancer and 584 controls matched according to age (+ 5yrs) and hospital were interviewed for the case control study. A detailed quantitative food-frequency questionnaire was used to assess the usual intake of 36 food items comprising 90% of commonly used foods in Karachi.
Results:
We estimated the mean daily intake of food items among both cases and controls. Conditional logistic regression analysis assessed the association between tertiles of intake of each food item and BC, adjusting for age at menopause, family history of breast cancer and parity. Consumption of deep fried sweet and fattyfood item of halwa poori was positively associated with breast cancer risk [adjusted odds ratio (OR) comparing the highest to the lowest tertile: 1.71, 95% confidence interval (CI): 1.16-2.52]. We also observed a positive and graded association between the intake of each of the following food items and BC; fish (OR=1.66, CI: 1.11, 2.49), fried potatoes (OR=1.85, 1.21,2.81). Conversely we observed an inverse association between breast cancer and the intake of green tea with higher levels being protective (highest compared to lowest tertile OR= 0.17, CI 0.03-0.88). Milk dessert (OR= 0.54;CI 0.35,0.82) was also protective against breast cancer.
Conclusions:
Our study indicates that frequent consumption of deep fried food items increse the risk of breast cancer. The unexpected association of breast cancer with fish may also be explained by its deep frying. Promoting a 'healthy' diet of a reduced consumption of fried food items is recommended. Green tea and milk desserts seem important protective factors from public health perspective.