Modifiable (Sleeping Pattern and Stress) and Non-Modifiable Risk Factors Associated with Breast Cancer: A Matched Case-Control Study in Delhi, India

Background: An utmost increase of breast cancer burden during the last several decades was reported in Asian countries. Findings from literature confirm that risk factors of breast cancers can be modifiable and non-modifiable in nature.

Objective: The present study is designed to identify specific modifiable and non-modifiable risk factors associated with breast cancer.

Methods: A matched case-control study was conducted considering 187 cases as women diagnosed with breast cancer and 187 hospital-controls as women without having breast cancer visiting the hospital. Other than standard risk factors, stress is measured using Perceived Stress Scale (PSS) and stress is measured using Pittsburgh Sleep Quality Index (PSQI). Several modifiable and non-modifiable risk factors were assessed using conditional logistic regression to find out significant association with breast cancer.

Results: Regular multi-vitamin uptake (OR = 3.38; 95%CI = 1.69 - 6.77; p-value = 0.001), poor sleep (OR = 11.29; 95%CI = 4.36 - 29.25; p-value < 0.001), irregular sleep (OR = 34.11; 95%CI = 10.03 - 115.92; p-value < 0.001) and severe stress (OR = 6.74; 95%CI = 3.06 - 14.81; p-value < 0.001) were found to be the highest odds ratio among all modifiable risk factor of breast cancer. Also, age at first childbirth less than 30 years (OR = 0.44; 95%CI = 0.25 - 0.78; p-value = 0.005) was found protective against breast cancer.

Conclusion: In our study, stress, sleeping pattern, and regular multi-vitamin uptake were found to be significant modifiable risk factors of breast cancer. None of the non-modifiable risk factors were found to be significantly associated with the risk of breast cancer.