Diet and risk of breast, endometrial and ovarian cancer: UK Women’s Cohort Study

This study aimed to investigate associations between diet and the risk of breast, endometrial and ovarian cancer in the UK Women’s Cohort Study. 35,372 women aged 35-69 years were enrolled between 1995 and 1998 and completed a validated 217-item food frequency questionnaire. The individual foods were collapsed into 64 main food groups, compared using Cox proportional models, adjusting for potential confounders. Hazard ratio (HR) estimates are presented per portion increase of food items. After approximately 18 years of follow-up, there were 1822, 294, and 285 cases of breast, endometrial and ovarian cancer respectively. A high consumption of processed meat and total meat was associated with an increased risk of breast and endometrial cancer. High intakes of tomatoes (HR: 0.87, 99% confidence interval (CI): 0.75 to 1.00) and dried fruits (HR: 0.60, 99% CI: 0.37 to 0.97) were associated with a reduced risk of breast and endometrial cancer respectively. Mushroom intake was associated with a higher risk of ovarian cancer (HR 1.57, 99% CI: 1.09 to 2.26). Subgroup analysis by pre or post-menopausal cancer further demonstrated an association between processed meat intake and both postmenopausal breast cancer and endometrial cancer. Dried fruits intake was associated with a reduced risk of postmenopausal endometrial cancer (HR: 0.55, 99% CI: 0.31 to 0.98). Our findings suggest that while some foods may trigger the risk of these cancers, some foods may also be protective; supporting the call for further randomised controlled trials of dietary interventions to reduce risk of cancer among pre and postmenopausal women.