The global burden of bladder, kidney, and prostate cancers attributable to smoking from 1990 to 2021 and projections for the next two decades: A cross-sectional study.

Background: Smoking increases the risk of bladder and kidney cancers and is associated with a poorer prognosis in prostate cancer (PCa) patients, which poses a significant health and socioeconomic burden. Understanding the epidemiologic trends of urological cancers attributable to smoking is critical to developing targeted prevention strategies. This study examines global trends in the three urological cancers attributable to smoking from 1990 to 2021 and projects future trends over the next two decades.

Methods: Data were obtained from the Global Burden of Disease (GBD) 2021. Metrics included deaths, disability-adjusted life years (DALYs), age-standardized mortality rates (ASMR), and age-standardized DALY rates (ASDR), with uncertainty intervals (UIs). Burden comparisons were stratified by sex, age, and sociodemographic index (SDI). Temporal trends were analyzed using Joinpoint regression to calculate annual percentage change (APC) and average annual percentage change (AAPC), with 95% confidence intervals (CIs). Future trends were predicted using the autoregressive integrated moving average (ARIMA) model.

Results: Compared with 1990, the number of deaths of bladder cancer, kidney cancer and PCa attributable to smoking increased by 43%, 67%, and 31%, and the number of DALYs increased by 31%, 52%, and 29% in 2021. However, the corresponding age-standardized rates showed a downward trend (AAPCASMR of bladder cancer, -1.53; AAPCASDR of bladder cancer, -1.68; AAPCASMR of kidney cancer, -0.89; AAPCASDR of kidney cancer, -1.11; AAPCASMR of PCa, -2.10; AAPCASDR of PCa, -1.97). The burden was higher among males than females, with the highest burden observed in high-SDI regions. The ASMR and ASDR were found to have a non-linear positive correlation with SDI (RASMR of bladder cancer=0.574, p<0.001; RASDR of bladder cancer=0.580, p<0.001; RASMR of kidney cancer=0.792, p<0.001; RASDR of kidney cancer=0.783, p<0.001; RASMR of PCa=0.417, p<0.001; RASDR of PCa=0.436, p<0.001), although the greatest improvements over the past three decades were observed in high-SDI regions. Joinpoint regression analysis indicated a downward trend in global deaths and DALYs burden, and the ARIMA model predicted that the burden of related diseases will continue to decline through 2041 (ASMRbladder cancer=0.44; ASDRbladder cancer=8.56; ASMRkidney cancer=0.13; ASDRkidney cancer=2.82; ASMRPCa=0.28; ASDRPCa=4.28).

Conclusions: Smoking has imposed a substantial disease burden on urological cancers over the past three decades. While overall ASDR and ASMR are declining, the disease burden remains high among men, especially those in high-SDI areas. This emphasizes the need for increased tobacco control for these populations or regions.