Causes and predictors of premature death in the pars cohort study, Iran: a cohort study

While death in old age is inevitable, premature death at younger ages is within our control. Premature mortality (death < 70 years) is a crucial indicator of health status and access to healthcare, with variations observed across regions. In North Africa and the Middle East, ischemic heart disease (IHD), road injuries, stroke, and chronic kidney disease are projected to be the main causes of premature mortality. Unfortunately, few studies have been conducted on premature mortality worldwide. This study aimed to analyze the causes of premature death and associated risk factors within the Pars Cohort Study.

The Pars Cohort Study is a prospective cohort study conducted in Fars Province, Iran, involving 9,264 individuals aged 40-75 years, 53.8% of whom were women. We assessed participants from baseline (2012-2014) to 2021. The data were gathered through interviews, biological samples, and physical examinations. The causes of premature mortality, hazard ratios (HRs), and population attributable fraction (PAF) with 95% confidence intervals (95% CIs) for the variables were calculated.

Out of 388 deaths, 54% were premature. The most common causes of premature death included IHD (40%), stroke (11%), road traffic injuries (6%), lower respiratory infections (5%), and COVID-19 (3%). The predictive factors [adjusted HRs (95% CIs)] associated with premature mortality included age [year, 1.07 (1.04, 1.10)], tobacco [1.43 (0.96, 2.11)], opium [2.12 (1.39, 3.24)], hypertension [1.52 (1.10, 2.12)], waist circumference [cm, 1.03 (1.00, 1.05)], female sex [0.30 (0.19, 0.47)], education [> 8 years vs. no formal schooling, 0.46 (0.24, 0.88)], being married [0.60 (0.37, 0.97)], physical activity [3rd vs. 1st tertile, 0.38 (0.26, 0.57)], hip circumference [cm, 0.96 (0.92, 0.99)], estimated GFR [mL/min/1.73 m², 0.99 (0.978, 0.999)], and wealth score [4th vs. 1st quartile, 0.54 (0.32, 0.90)]. The PAF (95% CI) for all modifiable predictors was 0.83 (0.62, 0.92).

The predominant causes of premature mortality were IHD and stroke. To mitigate premature deaths, it is recommended to address both socioeconomic and behavioral factors simultaneously.