Takaaki Konishi1,2, Michimasa Fujiogi3,4, Nobuaki Michihata5, Hiroki Matsui3, Masahiko Tanabe6, Yasuyuki Seto6, Hideo Yasunaga3. 1. Department of Breast and Endocrine Surgery, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. takaakonishi-ncd@umin.ac.jp. 2. Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. takaakonishi-ncd@umin.ac.jp. 3. Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. 4. Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, 125 Nashua Street, Suite 920, Boston, MA, 02114, USA. 5. Department of Health Services Research, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan. 6. Department of Breast and Endocrine Surgery, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
Abstract
PURPOSE: The association between body mass index (BMI) and the incidence of premenopausal breast cancer in the Asian population remains unclear. We investigated this association using data from a Japanese nationwide administrative database. METHODS: We retrospectively identified 785,703 females aged < 45 years with available health checkup data on BMI from January 2005 and April 2020 from a Japanese nationwide database. Cox proportional hazards model was used to estimate hazard ratios for breast cancer (total breast cancer, breast cancer with hormonal drug and trastuzumab administration, and breast cancer by age ≤ 45 years) associated with BMI recorded at the first health checkup. We conducted restricted cubic spline analysis without BMI categorization to investigate potential nonlinear associations with adjustment for backgrounds such as smoking and alcohol consumption. RESULTS: Overall, the median BMI was 20.5 (interquartile range [IQR], 18.9-22.7) kg/m2, and the median age was 37 (IQR, 29-41) years. Breast cancer occurred in 5597 participants (0.71%) at a median age of 44 (IQR, 42-46) years during a median follow-up of 1034 (IQR, 634-1779) days. A BMI of ≥ 22.0 kg/m2 was significantly associated with lower incidences of total breast cancer, breast cancer with hormonal drug administration, and breast cancer by age ≤ 45 years, whereas no significant associations were observed for breast cancer with trastuzumab administration. CONCLUSION: This study, which used a Japanese nationwide database, demonstrated that BMI was inversely associated with premenopausal breast cancer development in Japanese women, similar to that observed in Western women.
PURPOSE: The association between body mass index (BMI) and the incidence of premenopausal breast cancer in the Asian population remains unclear. We investigated this association using data from a Japanese nationwide administrative database. METHODS: We retrospectively identified 785,703 females aged < 45 years with available health checkup data on BMI from January 2005 and April 2020 from a Japanese nationwide database. Cox proportional hazards model was used to estimate hazard ratios for breast cancer (total breast cancer, breast cancer with hormonal drug and trastuzumab administration, and breast cancer by age ≤ 45 years) associated with BMI recorded at the first health checkup. We conducted restricted cubic spline analysis without BMI categorization to investigate potential nonlinear associations with adjustment for backgrounds such as smoking and alcohol consumption. RESULTS: Overall, the median BMI was 20.5 (interquartile range [IQR], 18.9-22.7) kg/m2, and the median age was 37 (IQR, 29-41) years. Breast cancer occurred in 5597 participants (0.71%) at a median age of 44 (IQR, 42-46) years during a median follow-up of 1034 (IQR, 634-1779) days. A BMI of ≥ 22.0 kg/m2 was significantly associated with lower incidences of total breast cancer, breast cancer with hormonal drug administration, and breast cancer by age ≤ 45 years, whereas no significant associations were observed for breast cancer with trastuzumab administration. CONCLUSION: This study, which used a Japanese nationwide database, demonstrated that BMI was inversely associated with premenopausal breast cancer development in Japanese women, similar to that observed in Western women.
Authors: K Wada; C Nagata; A Tamakoshi; K Matsuo; I Oze; K Wakai; I Tsuji; Y Sugawara; T Mizoue; K Tanaka; M Iwasaki; M Inoue; S Tsugane; S Sasazuki Journal: Ann Oncol Date: 2014-01-10 Impact factor: 32.976