The association between dietary acid load index with tumor stage and size, histological grade, Ki-67 marker, and the odds of breast cancer: a case-control study based on hospital evidence

Several observational and ecological studies have found a positive association between dietary acid load (DAL) and increased risk of chronic diseases. There is limited evidence suggesting that an acidic environment may promote the growth of certain cancer cells and tumors. Therefore, this study aims to determine the association between the DAL and Pathobiological markers of breast cancer (BC) and the risk of BC in Iranian women. In this hospital-based case-control study, 155 newly diagnosed women with BC, confirmed by histopathological examination, were selected using convenience sampling. Based on the inclusion criteria, the patient group was recruited from Javad Al-Aemeh Clinic in Kerman City, Iran, from September 2021 to March 2023. The DAL was estimated based on a 168-item Food Frequency Questionnaire (FFQ). The odds of BC (95% CI) according to potential renal acid load (PRAL), net endogenous acid production (NEAP), and net acid excretion (NAE) tertiles compared to the reference (OR = 1) were measured using logistic regression, with adjustment for potential confounders. Using linear regression, no significant associations were observed between NEAP and NAE estimates and tumor size or the Ki-67 marker ( p > 0.05). In logistic regression models, the Odds ratios (95%CI) for BC across tertiles of NEAP and NAE showed no significant associations with BC risk, either before or after adjustment for potential confounders ( p > 0.05). According to the findings, DAL was not significantly associated with the risk of BC. High-quality prospective studies are necessary to further specify the relationship between DAL and the risk of BC among the Iranian population.