Meat intake, methods and degrees of cooking and breast cancer risk in the MCC-Spain study

To analyse the relationship of the risk of breast cancer (BC) to meat intake, preference regarding degree of cooking ('doneness') and cooking methods, using data from a population-based case-control study (MCC-Spain).

1006 Histologically confirmed incident BC cases and 1370 controls were recruited in 10 Spanish provinces. Participants were 23-85 years old. They answered an epidemiological survey and a food frequency questionnaire. BC risk was assessed overall, by menopausal status and by pathological subtypes, using logistic and multinomial regression mixed models adjusted for known confounding factors and including province as a random effects term.

Breast cancer and pathological subtype.

High total intake of meat (OR_Q4-Q1 (95% IC) = 1.39 (1.03-1.88)) was associated with increased BC risk among post-menopausal women. Similar results were found for processed/cured meat (OR_Q4-Q1 (95% IC) = 1.47 (1.10-1.97)), and this association was particularly strong for triple-negative tumours (ER-, PR- and HER2-) (OR_Q4-Q1 (95% IC) = 2.52 (1.15-5.49)). Intakes of well-done (OR_{well-donevsrare} (95% CI) = 1.62 (1.15-2.30)) and stewed (OR (95% CI) = 1.49 (1.20-1.84)) red meat were associated with increased BC risk, with a high risk observed for HR+ tumours (ER+/PR+ and HER2-). Pan-fried/bread-coated fried white meat, but not doneness preference, was associated with an increased BC risk for all women (OR (95% CI) = 1.38 (1.14-1.65)), with a stronger association for pre-menopausal women (OR (95% CI) = 1.78 (1.29-2.46)).

The risk of developing BC could be reduced by moderating the consumption of well-done or stewed red meat, pan-fried/bread-coated fried white meat and, especially, processed/cured meat.