Dong Hoon Lee1, NaNa Keum2,3, Leandro F M Rezende4, Fred K Tabung1,5, SungEun Hong6, Edward L Giovannucci1,7,8. 1. Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA. 2. Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA. nak212@mail.harvard.edu. 3. Department of Food Science and Biotechnology, Dongguk University, SangYeongBio building Room 543, Siksa-dong, Ilsandong-gu, Goyang-si Gyeonggi-do, 10326, South Korea. nak212@mail.harvard.edu. 4. Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Medicina Preventiva, Sao Paulo, SP, Brazil. 5. Division of Medical Oncology, Department of Internal Medicine, The Ohio State University College of Medicine and Comprehensive Cancer Center - James Cancer Hospital and Solove Research Institute, Columbus, OH, USA. 6. Department of Food Science and Biotechnology, Dongguk University, SangYeongBio building Room 543, Siksa-dong, Ilsandong-gu, Goyang-si Gyeonggi-do, 10326, South Korea. 7. Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA. 8. Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Abstract
PURPOSE: Weight cycling is common in populations. However, it is unclear whether frequency and magnitude of weight cycling is associated with kidney cancer risk, independent of body mass index (BMI). METHODS: A prospective cohort study followed 85,562 participants from Health Professionals Follow-up Study and Nurses' Health Study (1992-2014). At baseline, participants reported frequency and magnitude of intentional weight loss in the past 4 years. Cox proportional hazard model was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). We also conducted a meta-analysis of all available observational studies including our two cohorts. RESULTS: During 22 years of follow-up, we identified 441 kidney cancer cases. Compared with non-weight cyclers (no attempt of intentional weight loss), severe cyclers (≥ 3 times of intentional weight loss of ≥ 4.5 kg) were at increased kidney cancer risk after adjusting for BMI before weight cycling (pooled multivariable-adjusted HR, 1.78; 95% CI, 1.19, 2.66). Additional adjustment for attained BMI after weight cycling had minimal influence. There was a positive trend between weight cycling by frequency and magnitude and kidney cancer risk (P-trend = 0.01). Moreover, the observed positive association did not differ by subtypes of cyclers (e.g., adiposity status, weight-loss methods). In the meta-analysis, we found a strong positive association between weight cycling and kidney cancer risk (summary relative risk for weight cyclers vs. non-cyclers, 1.51; 95% CI, 1.16, 1.96; I2: 52.2%; 6 studies). CONCLUSION: Frequent substantial weight cycling was associated with increased risk of kidney cancer, independent of BMI. Our study suggests that weight cycling may be an important risk factor for kidney cancer.
PURPOSE: Weight cycling is common in populations. However, it is unclear whether frequency and magnitude of weight cycling is associated with kidney cancer risk, independent of body mass index (BMI). METHODS: A prospective cohort study followed 85,562 participants from Health Professionals Follow-up Study and Nurses' Health Study (1992-2014). At baseline, participants reported frequency and magnitude of intentional weight loss in the past 4 years. Cox proportional hazard model was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). We also conducted a meta-analysis of all available observational studies including our two cohorts. RESULTS: During 22 years of follow-up, we identified 441 kidney cancer cases. Compared with non-weight cyclers (no attempt of intentional weight loss), severe cyclers (≥ 3 times of intentional weight loss of ≥ 4.5 kg) were at increased kidney cancer risk after adjusting for BMI before weight cycling (pooled multivariable-adjusted HR, 1.78; 95% CI, 1.19, 2.66). Additional adjustment for attained BMI after weight cycling had minimal influence. There was a positive trend between weight cycling by frequency and magnitude and kidney cancer risk (P-trend = 0.01). Moreover, the observed positive association did not differ by subtypes of cyclers (e.g., adiposity status, weight-loss methods). In the meta-analysis, we found a strong positive association between weight cycling and kidney cancer risk (summary relative risk for weight cyclers vs. non-cyclers, 1.51; 95% CI, 1.16, 1.96; I2: 52.2%; 6 studies). CONCLUSION: Frequent substantial weight cycling was associated with increased risk of kidney cancer, independent of BMI. Our study suggests that weight cycling may be an important risk factor for kidney cancer.
Authors: Béatrice Lauby-Secretan; Chiara Scoccianti; Dana Loomis; Yann Grosse; Franca Bianchini; Kurt Straif Journal: N Engl J Med Date: 2016-08-25 Impact factor: 91.245