# Latent Trajectories and Regional Differences in Carbon Monoxide Mortality Across Provinces of Iran

## TL;DR

This study analyzes carbon monoxide poisoning deaths in Iranian provinces from 2011 to 2022, identifying regional trends and suggesting interventions to reduce mortality.

## Contribution

The novel use of growth mixture modeling to classify provinces based on COP mortality trends over time.

## Key findings

- Alborz and East Azerbaijan provinces reported the highest COP mortality rates over ten years.
- COP mortality rates in class 2 and class 4 provinces increased by three and two times, respectively.
- The study recommends public awareness and CO detector installation in colder regions to prevent poisoning.

## Abstract

Considering the geographic and socio-economic heterogeneity across Iranian provinces, studying carbon monoxide poisoning (COP) mortality trends can provide insight for decision-making and necessary interventions. This study aimed to model the trend of COP mortality across 31 provinces of Iran from 2011 to 2022.

The current study used data from the Iranian Legal Medicine Organization (ILMO), the official body responsible for certifying and registering all suspected COP deaths in Iran, from 2011 to 2022. The annual and 10-year cumulative mortality rates were calculated by sex for all provinces. The growth mixture model (GMM) was employed to classify provinces according to the magnitude of alterations in the COP mortality rate concerning the intercept and slope parameters, utilizing the R software and the lcmm package.

From 2011 to 2022, 9555 deaths due to COP were reported. The national 10-year cumulative mortality rate was 10.04 (95% CI: 8.34–11.75) per 100,000 for both sexes, 14.74 (12.37–17.12) for males, and 5.02 (4.06–6.34) for females. The Alborz Province for both sexes and males and the East Azerbaijan Province for females reported the highest mortality over ten years: 18.69 (17.25–20.19), 26.21 (23.93- 28.6), and 11.13 (7.34- 9.88) per 100,000 persons, respectively. The GMM results indicated that the overall COP mortality rate in class 2 and class 4 increased approximately by three and two times, respectively.

The rising trend of COP mortality in several provinces requires urgent interventions, focusing on safety and modern heating. Public awareness and CO detector installation, especially in colder regions, are crucial for preventing CO poisoning.