Background: Obesity is a known risk factor of breast cancer. However the contribution of different measures of obesity(BMI, WHR, WC and HC) and their role in pre- and postmenopausal women is still not clear.
Aim: To study the role of obesity in causation of breast cancer.
Methods:A hospital-based case control study was conducted in Tata Memorial Hospital during the period of January 2009 to September 2013. Questionnaire data was collected on 1637 breast cancer cases and 1515 female controls.
Results: Risk of BC increased in underweight women (BMI <18.5kg/m2) when compared to women with normal BMI of Asian category (18.5–22.9 kg/m2). The risk of developing BC in premenopausal women was 1.75 (95% CI: 1.16–2.65) whereas in postmenopausal women was 1.89 (95% CI: 1.09–3.29). A protective association observed in premenopausal women (OR = 0.93; 95% CI: 0.91–0.95) with per unit increase in BMI (world) continued in women who had attained menopause less than 10 years ago (OR = 0.95; 95% CI: 0.92–0.98). However the risk of BC increased in women in highest category of BMI (world) who had attained menopause ≥10 years ago from the date of enrolment (OR = 1.85; 95% CI: 1.05–3.28). With every 0.1 increase in WHR the risk of BC increased (OR = 1.69; 95% CI: 1.47–1.96) and (OR = 1.71; 95% CI: 1.41–2.00) in premenopausal and postmenopausal women respectively.
Conclusions:The study demonstrates that BC is preventable in India and is possible to reverse the increasing trend of BC. The strategies to reduce BMI should consider the cut-off of 18.5 kg/m2 as BMI lower than this might increase the risk for pre- and postmenopausal BC. Future studies on BC should include much more sophisticated measurement of central obesity and total body fat.