Causes of premature death and their associated risk factors in the Golestan Cohort Study, Iran

OBJECTIVES: To examine the causes of premature mortality (<70 years) and associated risk factors in the Golestan Cohort Study. DESIGN: Prospective. SETTING: The Golestan Cohort Study in northeastern Iran. PARTICIPANTS: 50 045 people aged 40 or more participated in this population-based study from baseline (2004–2008) to August 2017, with over 99% success follow-up rate. MAIN OUTCOME MEASURES: The top causes of premature death, HR and their 95% CI and population attributable fraction (PAF) for risk factors. RESULTS: After 444 168 person-years of follow-up (median of 10 years), 6347 deaths were reported, of which 4018 (63.3%) occurred prematurely. Ischaemic heart disease (IHD) accounted for 33.9% of premature death, followed by stroke (14.0%), road injuries (4.7%), stomach cancer (4.6%) and oesophageal cancer (4.6%). Significant risk/protective factors were: wealth score (HR for highest vs lowest quintile: 0.57, PAF for lowest four quintiles vs top quintile: 28%), physical activity (highest vs lowest tertile: 0.67, lowest two tertiles vs top tertile: 22%), hypertension (1.50, 19%), opium use (1.69, 14%), education (middle school or higher vs illiterate: 0.84, illiterate or primary vs middle school or higher: 13%), tobacco use (1.38, 11%), diabetes (2.39, 8%) and vegetable/fruit consumption (highest vs lowest tertile: 0.87, lowest two tertiles vs top tertile: 8%). Collectively, these factors accounted for 76% of PAF in men and 69% in women. CONCLUSION: IHD and stroke are the leading causes of premature mortality in the Golestan Cohort Study. Enhancing socioeconomic status and physical activity, reducing opium and tobacco use, increasing vegetable/fruit consumption and controlling hypertension and diabetes are recommended to reduce premature deaths.