Showing 3 results for Shakiba
M Shakiba, Ma Mansournia, H Soori,
Volume 13, Issue 1 (Vol 13, No 1, Spring 2017)
Abstract
Standard methods for estimating exposure effects in longitudinal studies will result in biased estimates of the exposure effect in the presence of time-dependent confounders affected by past exposure.
In the present review article, we first described the assumptions required for estimating the causal effect in longitudinal studies and their structure regarding various types of exposure and confounders; then, we explained the bias of standard methods in estimating the causal effect.
Two types of bias, i.e. over-adjustment bias and selection bias, occur in estimating the effect of time-varying exposure in the presence of time-dependent confounders affected by previous exposure using standard regression analysis. Standard regression methods cannot sufficiently modify time-dependent confounders and estimate the total causal effect of the exposure.
Mm Vakili, L Babakhani, S Sharifi, A Moazen, Z Mehrabi, K Kamali, M Namadian, E Shakibazadeh,
Volume 14, Issue 2 (Vol.14, No.2, 2018)
Abstract
Background and Objectives: The pandemic of HIV/AIDS is spreading rapidly in the Middle East, in particular in Iran. Designing an educational program involves assessment of the educational needs of people with valid and culture-based tools. This study was conducted with the aim of psychometric analysis of an instrument for assessment of HIV/AIDS knowledge based on the Iranian culture in different population groups.
Methods: In this psychometric analysis, 58 items related to AIDS knowledge were prepared based on a literature review. Then, the face validity and content validity of the instrument was determent by the impact item score, content validity ratio (CVR), and content validity index (CVI). The reliability of the scale was assessed by Cronbach’s alpha coefficient and test-retest.
Results: Based on face validity and content validity, the research scale had 44 items with an item impact score > 1.5, a CVR > 0.49, and a CVI > 0.79. The Scale had three sections, general knowledge about HIV/AIDS (9 items), knowledge about HIV transmission (25 items), and knowledge about HIV/AIDS prevention (10 items). The Scale also had a high reliability (Cronbach’s alpha coefficient=0.77-0.91, ICC=0.88)
Conclusion: The results of the study showed the instrument was a valid and reliable scale for measurement of knowledge about HIV/AIDS.
Maryam Aghajarinezhad, Yahya Salimi, Shahab Rezaeian, Ghobad Moradi, Fatemeh Khosravi Shadmani, Roya Safari Faramani, Ebrahim Shakiba, Yahya Pasdar, Behrooz Hamzeh, Nayebali Rezvani, Mitra Darbandi, Farid Najafi,
Volume 18, Issue 2 (Vol.18, No.2, Summer 2022 2022)
Abstract
Background and Objectives: Serological studies are based on the detection of antibodies. However, the produced antibodies decrease over time; therefore, such methods cannot provide a valid estimate of prevalence and incidence. The present study aimed to determine the serum prevalence and cumulative incidence in the Ravansar cohort population (Youth and RaNCD Cohort) in October 2020.
Methods: A random sample of 716 people aged > 18 years old were selected from the participants in the Ravansar cohort study in October 2020. Euroimmun anti-SARS COV-2 IgG ELISA kits (Lübeck, Germany) were used to measure antibody levels. Seroprevalence was estimated with considering of cut-off = 1, and cumulative incidence (modified and modified based on test specificity) was determined using modeling.
Results: In the present study, the serum prevalence of COVID-19 viral infection in the Ravansar cohort population from 22 October 2020 to 18 November 2020 was estimated to be %35.16 (95%CI: %31.64, %38.79). Modified Cumulative incidence and modified based on test characteristics from 20 February to 18 November 2020 were estimated to be %68.85 and %67.71, respectively.
Conclusion: Although very high cumulative incidence may be a sign of approaching herd immunity, adherence to health protocols is still recommended due to the potential role of asymptomatic cases in transmitting the disease to other members of the community; and the presence of new variants of the virus and reduced antibody levels should be considered.
