Association of body mass index with bladder cancer risk: a dose-response meta-analysis of prospective cohort studies

Limin Zhao,Junfang Huang,Xueyan Duan,Xiaoqin Tian,Min Sun,Yongxiu Ye

doi:10.18632/oncotarget.16722

Limin Zhao, Junfang Huang + Show 4 more

Open Access

https://doi.org/10.18632/oncotarget.16722

Copy DOI

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.

Highlights

Bladder cancer is among the most common malignancies of the genitourinary tract all over the world [1]
The Newcastle-Ottawa Scale (NOS) was applied to assess the quality of the included studies and the results showed all the studies were of high quality, with NOS score ≥7
When we fitted the linear dose-response model to regress the relative risks of bladder cancer on per 5 kg/m2 increase in body mass index (BMI) for each studies, the dose-response metaanalysis in random-effects model across all the studies showed that there was a weak positive association between BMI and bladder cancer risk, indicating that per 5 kg/ m2 increment on BMI corresponded to a 3.1 % increase of bladder cancer risk (The summary relative risk (SRR): 1.03, 95%confidence interval (CI): 1.01-1.06, p = 0.039) with evidence of no problems in the fitted model (Q = 51.85, p = 0.099)

Summary

Introduction

Bladder cancer is among the most common malignancies of the genitourinary tract all over the world [1]. The remaining ~25% of cases are muscle invasion. They still have poor outcome despite systemic therapy concerning radical surgery or radiotherapy [2]. Because the rising incidence of bladder cancer is alarming, a substantial challenge has been presented to public health. It is an increasing common view that making effective control measures to prevent form bladder cancer is more effective and significant [3]. Many studies have focused on risk factors for bladder cancer. It has been well established that cigarette smoking, occupational exposure to aromatic amines, and chronic schistosoma infection are significant etiological factor for bladder cancer [4, 5]

Methods

Results

Conclusion