Association between dietary fat and fat subtypes with the risk of breast cancer in an Iranian population: a case-control study

AIM: To examine the relationship between dietary fat intake and breast cancer (BC) development. METHOD: This case-control study included 473 women with breast cancer (pathologically confirmed) and 501 healthy subjects matched by age and residency. Dietary intakes of different types and sources of fatty acids were assessed using a validated food frequency questionnaire. The association between dietary fats and odds of BC was assessed using a logistic regression model in crude and multivariable-adjusted models. P values below 0.05 were regarded as statistically significant. RESULTS: Participants’ age and body mass index were 44.0 ± 10.8 years and 28.4 ± 5.6 kg/m(2), respectively. Individuals with the highest quartile of total fat intake and polyunsaturated fatty acid (PUFA) intake were 1.50 times more at risk to develop BC than others. A positive significant association was observed between animal fat (Q4 vs. Q1, OR = 1.89, 95 % CI = 0.93–3.81), saturated fatty acid (SFA) (Q4 vs. Q1, OR = 1.70, 95 % CI = 0.88–3.30), monounsaturated fatty acid (MUFA) (Q4 vs. Q1 OR = 1.85, 95 % CI = 0.95–3.61) and PUFA intake (Q4 vs. Q1, OR = 2.12, 95 % CI = 1.05–4.27) with BC risk in postmenopausal women. However, there was no association in premenopausal women. CONCLUSIONS: Total dietary fat and its subtypes might increase the risk of BC, especially in postmenopausal women. This observational study confirms the role of dietary fat in breast cancer development. Intervention studies involving different estrogen receptor subgroups are needed. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12944-021-01557-y.