Breast cancer risk factors, molecular subtypes and diagnosis in Bangladeshi women: insights from a case-control study of 290 participants

Breast cancer (BC) is the most common malignancy among women in Bangladesh (BD), with rising incidence and mortality, yet its risk factors remain inadequately defined. This study explored demographic, reproductive, lifestyle, metabolic, and molecular determinants of BC in Bangladeshi women. This case-control study included 206 BC patients and 84 healthy controls. Demographic, reproductive, lifestyle, metabolic, and molecular determinants were analyzed statistically using Chi-square, regression, Wilcoxon, and Spearman-Pearson correlation tests. Molecular subtype and treatment strategies in BC_BD cases were compared against the Cancer Genome Atlas (TCGA) BC dataset. Obesity (OR:3.09; p-value 0.037) and dyslipidemia (TG, OR:4.81, p-value 1.8e-06; TC, OR:3.36, p-value 4.17e-04; LDL, OR:3.07, p-value 0.001) were observed in nearly 90% of patients. BMI correlated positively with waist (r = 0.64, p-value 5.1e-14) and hip circumference (r = 0.59, p-value 8.64e-12). TG was associated with TC (r = 0.31, p-value 7.67e-04) and blood pressure (r = 0.26, p-value 0.005), while TC showed strong correlations with HDL and LDL (p-value 2.99e-25). Early menarche, early childbirth, postmenopausal status, sedentary lifestyle, and sleep disruption significantly increased BC risk. BC cases with type 2 diabetes and hypertension showed further clinical complexity. TNBC/Basal molecular-subtype prevailed (p-value 0.002) in BD cases, with strong hypoxia associations (p-value 0.002). In BD, despite comparable chemotherapy regimens to TCGA, hormone therapies were limited and HER2-targeted agents were absent, revealing treatment gaps. BC in Bangladeshi women reflects multifactorial risks, dominated by TNBC and hypoxia-driven biology, underscoring the need for precision, prevention and personalized care. • Breast cancer (BC) in Bangladeshi women shows rising incidence and mortality, with poorly characterized risk determinants. • Obesity and dyslipidemia were present in ~ 90% of patients and strongly associated with BC risk. • Comorbid conditions (like type 2 diabetes and hypertension) further added BC complexity, indicating synergistic metabolic-endocrine disruption. • Early menarche, early childbirth, postmenopausal status, sedentary lifestyle, and sleep disruption significantly increased BC susceptibility. • The TNBC/basal molecular subtype predominated and was strongly linked to hypoxia-driven biology. • Despite chemotherapy patterns similar to TCGA, hormone therapies were underused, and HER2-targeted agents were absent, highlighting treatment gaps in Bangladesh.