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

## TL;DR

This study examines the rise in prostate cancer deaths among Iranian men from 1990 to 2021, identifying age, period, and birth cohort effects to guide prevention strategies.

## Contribution

The study applies APC and joinpoint regression models to analyze prostate cancer mortality trends in Iran, revealing key age and period effects.

## Key findings

- Prostate cancer mortality rates increased significantly in Iran from 1990 to 2021, with a 2.254% annual rise in crude mortality.
- Relative risk of mortality increased with age, from 0.033 at ages 20–24 to 16.183 for those over 95 years.
- Later-born cohorts showed lower mortality rates compared to earlier-born cohorts, indicating a cohort effect.

## Abstract

Background: 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.

Method: 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.

Results: Crude and age-standardized mortality rates for PC were increasing, with AAPC of 2.254% (95% CI: 2.099% and 2.410%; p < 0.001) and 0.257% (95% CI: 0.088% and 0.428%; p < 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).

Conclusion: 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.