Fig. 2

Associations between C2 (a) and PC ae C36:3 (b) and breast cancer, by selected variables. CI: confidence interval; ER: estrogen receptor; HER2: human epidermal growth factor receptor 2; PC: phosphatidylcholine; PR: progesterone receptor; SM: sphingomyelin. Odds ratios (ORs) are estimated per standard deviation (SD) increase in log-transformed metabolite concentrations, from logistic regression conditioned on matching variables. Homogeneity was tested by adding an interaction term in the conditional logistic regression model for menopausal status, use of hormones at blood collection, fasting status, breast cancer subtype, and age at diagnosis (all matching factors or case characteristics). For waist circumference (non-matching factor), logistic regression adjusted for each matching factor was used