title: Association of body mass index with bladder cancer risk: a dose-response meta-analysis of prospective cohort studies.
abstract: Prospective epidemiologic studies on the association between body mass index (BMI) and bladder cancer yielded inconsistent findings. This study sought to quantitatively summarize the evidence by performing a dose-response meta-analysis on prospective cohort studies. Eligible studies were retrieved via PubMed and Embase databases, and by manual review of the references. Linear and nonlinear trend analyses were conducted to explore the relationships between BMI and bladder cancer risk. Meta-analyses on the categories of overweight and obesity were also conducted. The summary relative risk (SRR) was estimated. Heterogeneity across the studies was explored through subgroup analyses based on gender, age, year of publication, sample size, assessment of BMI, geographic location, physical activity and family history of cancer. A total of 14 prospective cohort studies involving 12,642 cases were included. Result of the dose-response analysis showed a nonlinear positive relationship between BMI and bladder cancer (SRR = 1.03, 95% CI: 1.01-1.06, P-nonlinearity =0.031), suggesting that per 5 kg/m2 increment on BMI corresponded to a 3.1 % increase of bladder cancer risk, especially BMI exceed 30kg/m2.Furthermore, significant positive association was also observed between obesity category and bladder cancer risk (SRR: 1.10, 95%CI: 1.03-1.17). In summary, this dose-response meta-analysis suggests a nonlinear positive association between BMI and bladder cancer risk. Further studies are required to confirm these findings and elucidate the pathogenic mechanisms.
authors.affiliation: Department of General Medicine, Shenzhen Longhua New District Central Hospital, Shenzhen, Guangdong, P.R. China.
authors.forename: Limin
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Endocrinology, Shandong Liaocheng City Central Hospital, Liaocheng, Shandong, P.R. China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Tian
authors.affiliation: Department of General Medicine, Shenzhen Longhua New District Central Hospital, Shenzhen, Guangdong, P.R. China.
authors.forename: Xueyan
authors.initials: X
authors.lastname: Duan
authors.affiliation: Department of General Medicine, Shenzhen Longhua New District Central Hospital, Shenzhen, Guangdong, P.R. China.
authors.forename: Yongxiu
authors.initials: Y
authors.lastname: Ye
authors.affiliation: Department of Urolgoy, The Xinjiang Uygur Autonomous Region Peoples Hospital, Uygur, Xinjiang, P. R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Sun
authors.affiliation: Department of General Medicine, Shenzhen Longhua New District Central Hospital, Shenzhen, Guangdong, P.R. China.
authors.forename: Junfang
authors.initials: J
authors.lastname: Huang
mesh_terms: D015992:Body Mass Index; D015331:Cohort Studies; D006801:Humans; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000209:etiology*
keywords: bladder cancer; body mass index; dose-response; meta-analysis; risk