A large-scale case-control study on the association between dietary fat quality indices and risk of breast cancer.

The relationship between breast cancer (BC) and total dietary and types of fat is well-established, however, the association with dietary fat quality (DFQ) indices remains to be elucidated. Therefore, the aim was to investigate the associations between DFQ indices and odds of BC among women. This hospital-based case-control study included 464 women with pathologically confirmed BC during the past year and 498 apparently healthy controls of similar age and residence. Dietary intake was assessed using a validated food frequency questionnaire (FFQ) and DFQ indices were calculated. The likelihood of BC was evaluated across tertiles of specific DFQ indices scores [atherogenicity index (AI), thrombogenic index (TI), hypo- and hypercholesterolemic fatty acids ratio (h/H), omega-3 to omega-6 polyunsaturated fatty acids ratio (∑ω-3/∑ω-6), polyunsaturated fatty acids/saturated fatty acids ratio (PSR), dietary lipophilic index (LI), cholesterol/saturated fat index (CSI)]. After controlling for several potential confounders, CSI was inversely associated with BC risk among all participants (OR: 0.53, 95% CI: 0.37-0.76; P = 0.001). This association remained significant after stratified analysis in pre-postmenopausal women. In addition, there were higher odds of BC in the highest category of PSR compared to the lowest category in among postmenopausal women (OR: 1.93; 95% CI: 1.07-3.48 P = 0.03). There were no other significant associations between BC risk and the other DFQ indices.PSR and CSI might be directly and inversely associated with the odds of BC, respectively. To confirm the causality of the associations, prospective cohort studies are needed.