Hospital-Based Study on the Association Between Physical Activity and Breast Cancer Risk in North East Indian Women
Background: Breast cancer (BC) is the most common female cancer worldwide, and the role of   physical activity has been linked to reduced risk of breast cancer through hormonal and metabolic pathways. Yet, evidence on North East India population is scarce.
Objective: This study aimed to evaluate the relationship between physical activity levels and BC risk.
Methods: A hospital-based case-control study was utilized. 106 histopathologically confirmed BC cases, and 100 visitor controls were included. Self-reported information was collected regarding physical activity and other potential confounders. Logistic regression model was used to calculate odds ratio (OR) and its 95% confidence interval (CI), after adjusting for age, current residential region, education, various reproductive factors and BMI. Attributable fraction (AF) and population attributable fraction (PAF) of BC due to physical activity was also calculated.
Results: Women with high physical activity had a significantly lower risk of BC compared to women with low activity (OR: 0.68, 95% CI: 0.50–0.92). A protective dose-response relationship was observed. The association was stronger among premenopausal women. The AF for low physical activity was estimated at 7%, and the PAF for North East India was about 5%.
Conclusion: Our study suggests that higher physical activity is associated with reduced BC risk, for all subtypes. This is particularly true when among premenopausal women. This highlights the need to target strengthen public health policies and awareness programs promoting physical activity, thus reducing the burden of BC to some extent.