Dietary patterns and risk of cancer of various sites in the Norwegian European Prospective Investigation into Cancer and Nutrition cohort: the Norwegian Women and Cancer study.

An indicator of common diets among groups of individuals can be found by identifying dietary patterns. We found previously six dietary patterns in the Norwegian European Prospective Investigation into Cancer and Nutrition cohort and labelled them fish, healthy, average, western, bread and alcohol. We examined the relationship between the different patterns and risk of total cancer, breast cancer and gastrointestinal cancers in 34 471 women from the Norwegian European Prospective Investigation into Cancer and Nutrition cohort, in which there were 1355 cancer cases. The hazard ratios and their corresponding 95% confidence intervals were estimated using Cox proportional hazards regression. Stratified analysis on menopausal status and smoking status was performed. Alcohol, meat, fish and fruit and vegetable consumption are suspected to have an influence on different cancers; thus we decided to perform stratified analysis on high versus low consumption of the above-mentioned variables as well. We found no overall relationship between cancers and the six different dietary patterns in this study. When stratifying on alcohol consumption, fruit and vegetable consumption and fatty fish consumption, there was a statistically higher risk of total cancer and breast cancer with high alcohol consumption, and a significantly higher risk of breast cancer with low consumption of fruit and vegetables or with low consumption of fatty fish in the western group only. A significantly higher risk of total cancer with low intake of fatty fish in the alcohol group was also observed.