The question of whether dichlorodiphenyltrichloroethane (DDT) exposure is related to breast cancer (BC) remains unanswered, possibly due to methodological constraints in the studies that have been performed. We aimed to update and synthesize the available epidemiological evidence on the relationship of p,p′-DDT, o,p′-DDT and p,p′-dichlorodiphenyldichloroethylene (p,p′- DDE) biological concentrations with female BC, focusing in methodological characteristics not addressed in previous reviews. We conducted an overview of reviews and a systematic review and meta-analysis. We used six databases and one search engine to identify meta-analyses based on systematic reviews, pooled analyses, and individual studies published from January 2000 to December 2021. For the overview of reviews, we assessed meta-analyses’ risk of bias and carried out a narrative synthesis. For the meta-analysis, we estimated summary association measures with fixed or random effects models for each compound stratifying for characteristics of interest. We estimated a positive summary association between p,p′- DDT biological concentrations and BC in prospective studies (nested case control) with >10 years of follow-up (sOR=1.41; 95 %CI: 1.06–1.88). Among retrospective studies (hospital or population-based case-control), BC was positively related with p,p’-DDE biological concentrations (sOR=1.15; 95 %CI: 1.02–1.30), and with p,p’-DDT in women with mean serum concentrations>100 ng/g (sOR=1.33; 95 %CI: 1.25–1.41). Moreover, we detected a positive association between o,p′-DDT and BC (sOR=2.24; 95 %CI: 2.15–2.34). Our results support a positive relationship between DDT exposure and BC, and are useful to reinforce its worldwide prohibition, since this pesticide is still used in some countries, has long persistence in the human body and disseminates to other geographic areas.

The Atoyac river basin is one of the most polluted watershed basins in Mexico. Recent studies have reported the presence of organochlorine pesticides (OCPs) in this highly urbanized region through environmental monitoring, raising concerns about potential health risks, particularly for children and adolescents. We still lack information about its human exposure through biological samples that represent a more realistic measure of OCPs body burden. To evaluate, we compared the serum concentrations of OCPs in children and adolescents living within and outside the Atoyac watershed basin. We included 428 individuals under 20 years old who participated as controls in a population‐based study conducted in three central‐southern Mexican states (2021–2024). We collected sociodemographic characteristics through face‐to‐face interviews and obtained serum samples in which we quantified 24 OCPs by gas chromatography. To georeference, we classified the participants as living within or outside the Atoyac basin and compared their respective serum concentrations for those OCPs detected over 10% of samples. We found two heterogeneous spatial distribution patterns of OCPs serum concentrations. HCB, dieldrin, oxychlordane, and endosulfan sulfate were higher in the Atoyac basin, with the two formers being statistically significant. In contrast, p , p ′‐DDE was significantly higher outside the Atoyac basin. The two patterns of exposure between the two regions emphasized one pattern driven by industry and agriculture, and the second driven by vector‐borne disease control. It reinforces the need for regulation and increased monitoring in the Atoyac river basin to provide information about adverse health effects in children and adolescents.