Abstract
BACKGROUND: Results from studies investigating the association between ultra-processed foods (UPFs) and breast cancer are scarce and, in some cases, contradictory. Therefore, we aimed to evaluate the association between the intake of processed foods (PFs) and UPFs with the risk of breast cancer in Iranian women. METHODS: The present case (n = 133) - control (n = 266) study was carried out at two general hospitals in Tehran, Iran. A 168-item semi-quantitative food frequency questionnaire was used to assess the participants' dietary intake. Also, the NOVA classification was used to identify PFs and UPFs. The association between PFs and UPFs with the odds of breast cancer was analyzed using logistic regression models. RESULTS: According to Model 1 of conditional logistic regression, the odds of breast cancer were higher in the last tertile of UPFs than in the first tertile (odds ratio (OR) = 1.930; 95% confidence interval (CI): 1.080-3.449). In Model 2, no significant association was observed between the second and last tertiles of PFs and UPFs with the odds of breast cancer compared to the reference tertile. Also based on menopause status, the odds of breast cancer increased in the last tertile only among premenopausal women in Model 2 (OR = 3.656; 95% CI: 1.326-10.079). CONCLUSIONS: This study demonstrated that higher consumption of UPFs is associated with higher odds of breast cancer in premenopausal women.