Waist circumference and risk of breast cancer in Korean women: A nationwide cohort study

• Published in: International journal of cancer Vol. 142; no. 8; pp. 1554 - 1559
• Main Authors: Lee, Kyu Rae, Hwang, In Cheol, Han, Kyung Do, Jung, Jinhyung, Seo, Mi Hae
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 15.04.2018
• Subjects: Adipose tissue; Asian; Body fat; Body mass; Body mass index; Breast cancer; Cancer; Cohort analysis; Hazard identification; Health risk assessment; Health risks; Hormone replacement therapy; Medical research; menopause; Obesity; Post-menopause; Risk factors; Statistical analysis; Statistical models; waist circumference; Womens health; breast cancer; menopause; waist circumference; Asian; body mass index; obesity
• ISSN: 0020-7136; 1097-0215
• DOI: 10.1002/ijc.31180

Although postmenopausal breast cancer (BC) risk has been linked to adiposity, associations between adiposity and premenopausal BC remain unclear. To address this question, we investigated the association of BC risk with measures of adiposity, including body mass index (BMI) and waist circumference (WC), in a large cohort of Asian women. We used a nationwide cohort of adult Korean women selected from the National Health Insurance Corporation database merged with national health examination data from 2009 to 2015. A total of 11,227,948 women were tracked to retrospectively identify incident cases of BC. Our analysis used Cox proportional hazards models to calculate hazard ratios and assess the association of BC risk with BMI and/or WC in both pre‐ and postmenopausal women. BMI and WC were robustly associated with increased risk for postmenopausal BC (ptrend<0.001 for both BMI and WC) but not with premenopausal BC. Association between WC and premenopausal BC was only statistically significant when considering BMI (ptrend=0.044). In contrast, postmenopausal BC was negatively associated with WC when considering BMI (ptrend=0.011). In premenopausal women, WC may predict increased BC risk when considering BMI. However, in postmenopausal women, WC is not superior to BMI as an indicator of BC risk. What's new? While excess body fat is a risk factor for postmenopausal breast cancer, whether a similar link exists between adiposity and premenopausal breast cancer risk remains uncertain. Here, among Korean women, both body mass index (BMI) and waist circumference were strongly associated with postmenopausal breast cancer risk. BMI was inversely associated with premenopausal breast cancer risk. In all women, BMI adjustment modified associations between waist circumference and breast cancer risk. The findings suggest that unlike postmenopausal breast cancer, where general and central obesity independently predict risk, premenopausal breast cancer risk is predicted by central obesity only when general adiposity is considered.