Objectives Cardiovascular mortality in Western Asia is high and still rising. However, most data documented on risk prediction has been derived from Western countries and few population-based cohort studies have been conducted in this region. The current study aimed to present the process of pooling data and cardiovascular disease (CVD) mortality incidences for four Iranian cohorts.
Methods From the Iran Cohort Consortium, the Golestan Cohort Study (GCS), Tehran Lipid and Glucose Study, Isfahan Cohort Study (ICS) and the Shahroud Eye Cohort Study (ShECS) were eligible for the current study since they had appropriate data and follow-up visits. Age-standardised CVD mortality rates were estimated for ages 40–80 and 40–65 years. Cox regression was used to compare mortalities among cohorts. Adjusted marginal rates were calculated using Poisson regression.
Results Overall, 61 291 participants (34 880 women) aged 40–80 years, free of CVD at baseline, were included. During 504 606 person-years of follow-up, 1981 CVD deaths (885 women) occurred. Age-standardised/sex-standardised premature CVD mortality rates were estimated from 133 per 100 000 person-years (95% CI 81 to 184) in ShECS to 366 (95% CI 342 to 389) in the GCS. Compared with urban women, rural women had higher CVD mortality in the GCS but not in the ICS. The GCS population had a higher risk of CVD mortality, compared with the others, adjusted for conventional CVD risk factors.
Conclusions The incidence of CVD mortality is high with some differences between urban and rural cohorts in Iran as a Western Asian country. Pooling data facilitates the opportunity to globally evaluate risk prediction models.
- cardiovascular diseases
- cohort studies
- epidemiology of cardiovascular diseases
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Contributors NF designed the study’s analytic strategy, did statistical analysis and wrote the first draft of the manuscript and interpreted the results. DK supervised the work and contributed in the study design, statistical analysis, writing the manuscript and interpreting the results. SGS did some statistical analysis and contributed in writing the manuscript and interpreting the results. RM and FA provided the intellectual input and designs, supervised the data collection, endorsed the protocols to be followed in the study and commented on the draft manuscript. MAM and FF contributed in the study design, provided technical advice for statistical analysis and interpreted the results. HR, MHE, FH, HP, MM, HH, MS and AP contributed in data collection, harmonising the data and preparing the manuscript with critical appraisal. EWS and AF supervised the work, provided technical advice for statistical analysis, interpreted the results and revised the manuscript critically. All authors approved the manuscript to be published.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Ethics approval This study was approved by the institutional review board of Tehran University of Medical Sciences, Tehran, Iran.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.