Prostate Cancer Mortality in Iranian Men During 1990–2021: An Age‐Period‐Cohort and Joinpoint Regression Analysis

<b>Background:</b> Prostate cancer (PC) ranks as the third cause of cancer-related deaths among Iranian men. The age-period-cohort (APC) model helps identify critical ages, periods, and high-risk birth cohorts to prevent and control PC. Thus, this research aimed to evaluate the effect of APC on PC mortality in Iran from 1990 to 2021. <b>Method:</b> Our data include the number of PC deaths and population, collected by the Global Burden of Disease (GBD) and categorized by 5-year age groups. We computed average annual percentage changes (AAPCs) and relative risks by using joinpoint regression analysis and APC models, respectively. <b>Results:</b> Crude and age-standardized mortality rates for PC were increasing, with AAPC of 2.254% (95% CI: 2.099% and 2.410%; <i>p</i> < 0.001) and 0.257% (95% CI: 0.088% and 0.428%; <i>p</i> < 0.001), respectively. Furthermore, an increase occurred in both age effect from ages 20-24 years (RR = 0.033; 95% CI: 0.023 and 0.046) to over 95 years (RR = 16.183; 95% CI: 14.702 and 17.814) and the period from 1992 (RR = 0.542; 95% CI: 0.516 and 0.570) to 2021 (RR = 1.892; 95% CI: 1.809 and 1.979). While, the cohort effect demonstrated a lower mortality rate in later born than earlier born (Coef = 2.302 for the < 1901 cohort compared to Coef = -2.249 for the 2002-2006 cohort). <b>Conclusion:</b> Our study indicated that the trend of PC deaths in Iran increased during 1990-2021, and the period effect confirms this. Considering fewer deaths in high-income countries due to the widespread implementation of PSA testing, the occurrence of the aging phenomenon in our country, and the upward trend in deaths related to the age effect, sensitizing people and policymakers to conduct PSA screening seems necessary.