Unraveling breast cancer risk with a focus on menopausal status: a large case-control study

Breast cancer (BC) remains a major global health issue, influenced by modifiable factors like lifestyle and diet, and non-modifiable factors such as genetics. This study assesses their impact on BC among pre- and post-menopausal women in South India using a large, age-matched, population-based case-control design.

We analyzed epidemiological risk factors for BC overall and stratified by menopausal status. A total of 3,043 newly diagnosed BC cases from the Regional Cancer Centre, Thiruvananthapuram, and age-matched controls from the general population of Kerala, recruited through face-to-face interviews (2017-2023). Odds-ratios (OR) and 95% Confidence-Interval (CI) were estimated using conditional-logistic regression model.

Independent modifiable risk-factors for BC (OR;CI) among all women were frequent fried-food consumption (3.9;3.2-4.7), low vigorous-activity (2.7;2.2-3.4), low moderate-activity (2.4;1.8-3.3), more light-activity (2.2;1.8-2.6), high body-mass-index (1.5;1.1-1.8) and non-modifiable risk-factors were benign-breast-disease (4.9;3.4-7.2), prior-chest radiation (3.4;1.9-5.8), prior-pesticide exposure (2.5;1.4-4.2), family-history of BC (2.0;1.5-2.6) and family-history of other cancers (1.4;1.1-1.6), post-menopause women (1.4;1.02-1.9) and early menarche (1.3;1.03-1.7). In the stratified analyses, the independent factors among pre-menopausal women were fried-food consumption, physical inactivity, high body-mass-index, benign-breast-disease, prior-pesticide exposure, prior-chest radiation, and late first delivery were significant. Among post-menopausal women, the significant factors included fried food consumption, physical inactivity, higher waist-to-hip ratio, history of abortion, thyroid disease, benign-breast-disease, family-history of BC, family-history of other cancers, prior-pesticide exposure and prior-chest radiation.

Non-modifiable factors consistently influenced BC risk across groups, modifiable-factors were more critical among post-menopausal women. Targeted prevention strategies that promote physical activity, and weight management could significantly reduce the risk of breast cancer.