This study conducted in Dena County is a population-based cohort study as part of the Prospective Epidemiological Research Studies in Iran (PERSIAN). The specific objectives of this study were to estimate the prevalence of region-specific modifiable risk factors and their associations with the incidence of major non-communicable diseases (NCDs).

This PERSIAN Dena Cohort Study (PDCS) was conducted on 1561 men and 2069 women aged 35–70 years from October 2016 in Dena County, Kohgiluyeh and Boyer-Ahmad Province, Southwest Iran. The overall participation rate was 82.7%.

Out of 3630 participants, the mean age was 50.16 years, 2069 (56.9%) were women and 2092 (57.6%) were rural residents. Females exhibited higher prevalence rates of diabetes, hypertension, fatty liver, psychiatric disorders, thyroiditis, kidney stones, gallstones, rheumatic disease, chronic lung disease, depression and osteoporosis compared with males (p126 mg/dL, low-density lipoprotein >100 mg/dL and haematuria, respectively; most of them were female and urban people (p

PDCS will be planned to re-evaluate NCD-related incidence, all-cause and cause-specific mortality every 5 years, along with annual follow-up for 15 years. Some examples of additional planned studies are evaluation of genetic, environmental risk, spirometry and ECG tests.

It is well known that the COVID-19 pandemic has had a devastating impact on mental health, especially among individuals with long COVID. This systematic review and meta-analysis aims to investigate the prevalence of depression, stress and suicide tendencies among individuals with long COVID, as well as to explore the factors that contribute to these conditions.

A comprehensive review of literature will be conducted in various databases of including PubMed, including Medline, Embase, PsycINFO, CINAHL and Cochrane Library. The studies to be included in this review will be published in the English language, and the time frame of included studies will be from the date of inception of COVID-19 until 30 December 2023. Two independent reviewers will identify studies for inclusion based on a screening questionnaire, and the JBI standardised critical appraisal checklist for studies reporting prevalence data will be used to assess the methodological quality. The strength of the body of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. To analyse the data, a robust Bayesian approach will be applied using the STATA software package (V.14; STATA) and JASP software. The findings of this systematic review and meta-analysis will provide valuable insights into the prevalence of depression, stress and suicide tendencies among individuals with long COVID, as well as the factors that contribute to these conditions.

There is no research ethics board approval required. The dissemination plan is to publish results in a peer-reviewed academic journal.

CRD42022346858.