The association between metabolic syndrome and bladder cancer susceptibility and prognosis: an updated comprehensive evidence synthesis of 95 observational studies involving 97,795,299 subjects

Abstract

BackgroundThe association between metabolic syndrome (MS) and bladder cancer (BC) was not fully investigated, and most primary studies and pooled analyses were only focused on certain specific components.ObjectiveTo further investigate this issue and obtain more precise findings, we conducted this updated evidence synthesis of published studies, which involved not only MS components but also the MS in its entirety.Materials and methodsWe searched the PubMed, EMBASE, and Web of Science databases for observational studies on the association between BC susceptibility and/or mortality, and MS and its components. We extracted data from included studies, evaluated heterogeneity, and performed meta-analytic quantitative syntheses.ResultsA total of 95 studies with 97,795,299 subjects were included in the present study. According to the results, MS significantly increased the risk of BC (risk ratio [RR]=1.11, 95% CI=1.00–1.23); diabetes significantly increased the risk of BC (RR=1.29, 95% CI=1.19–1.39) and associated with poor survival (RR=1.24, 95% CI=1.08–1.43). Excessive body weight was associated with increased susceptibility (RR=1.07, 95% CI=1.02–1.12), recurrence (RR=1.46, 95% CI=1.18–1.81), and mortality (RR=1.17, 95% CI=1.00–1.37). As indicated by cumulative meta-analysis, sample size was inadequate for the association between BC susceptibility and MS, the association between BC recurrence and excessive body weight, and the association between BC survival and diabetes. The sample size of the meta-analysis was enough to reach a stable pooled effect for other associations.ConclusionDiabetes and excessive body weight as components of MS are associated with increased susceptibility and poor prognosis of BC. Uncertainty remains concerning the impact of overall MS, hypertension, and dyslipidemia on BC susceptibility and prognosis, for which further investigations are needed.

Association of NAFLD and Insulin Resistance with Non Metastatic Bladder Cancer Patients: A Cross-Sectional Retrospective Study

“…Beyond smoking, other risk factors for BCa have been studied, including metabolic syndrome (MS), obesity, and type 2 diabetes mellitus (T2DM) [ 3 , 4 , 5 ]. Based on large cohorts, T2DM significantly increased the risk of BCa [ 6 , 7 ], but findings from a meta-analysis suggest that individuals with T2DM may have a modestly increased risk of BCa [ 8 ] or none according to a population-based case-control study [ 9 ]. Still, analysing a vast population, data do not support an association of T2DM with overall bladder cancer incidence from 1992 through 2007 [ 10 ].…”

Preoperative Serum Gamma-Glutamyltransferase as a Prognostic Biomarker in Patients Undergoing Radical Cystectomy for Bladder Cancer

“…The recent publication has reported the similar result (HR: 1.03, 95% CI: 1.01-1.05) (22). In 2018, Peng et al (23) have performed an updated meta-analysis to examine the relationship between metabolic syndrome and susceptibility and prognosis of bladder cancer. The pooled results indicated that diabetes history significantly increased the risk of bladder cancer and was associated with poor survival.…”

Carbohydrates, Glycemic Index, and Glycemic Load in Relation to Bladder Cancer Risk

“…Well-established risk factors for bladder cancer include tobacco smoking and exposure to certain chemicals in the working and general environments (3). Emerging evidence has shown that metabolic syndrome, obesity, low physical activity, and type 2 diabetes are related to an increased risk of bladder cancer (4)(5)(6)(7)(8), suggesting that insulin resistance may play a role in the etiology of bladder cancer.…”