Lifestyle, reproductive factors, and gene expression patterns in breast cancer among rural Indian women

Breast cancer is one of the most common cancers among women, accounting for over 23% of all cancer-related fatalities in India. This study aimed to identify the risk factors associated with breast cancer among women living in rural regions of Madhya Pradesh. A hospital-based retrospective case-control survey was conducted to investigate the association between lifestyle factors including anthropometric, demographic, and reproductive characteristics—and the odds of developing breast cancer. Age-matched data from 105 healthy controls and breast cancer patients without a prior family history were analyzed using univariate and multivariate methods, with risk estimated using Odds Ratio and 95% Confidence Intervals. The molecular subtypes were distributed as 12% Luminal A, 28% Luminal B, 36% Her2neu-enriched, and 25% TNBC. Early-onset breast cancer was observed in 19% of cases, with 8% classified as TNBC. Moderate risk factors included early age at marriage, with 40% of cases married before 18 years (OR = 2.1, 95% CI: 1.3–3.5), multiple pregnancies reported in 22% of cases (OR = 1.7, 95% CI: 1.0–2.9), and early onset of menopause observed in 60% of cases (OR = 1.8, 95% CI: 1.1–3.0). Breastfeeding was not associated with a suppressed protective effect (OR = 0.7, 95% CI: 0.4–1.2). Elevated body mass index (BMI) also contributed to risk, with 30.8% of cases classified as overweight (OR = 1.5, 95% CI: 1.0–2.3) and 13% as obese (OR = 2.4, 95% CI: 1.3–4.5). Transcriptomic analysis using data from 107 breast cancer patients and Weighted Gene Co-expression Network Analysis identified elevated expression of genes involved in cell–cell adhesion including, lymphocyte proliferation, and T cell activation pathways. This study is the first report from a rural population in Bhopal, and further research with larger cohorts is warranted.