Showing 7 results for Modeling
A Ahmadi, J Hasanzadeh, A Rajaefard,
Volume 4, Issue 2 (9-2008)
Abstract
Background & Objectives: Hypertension is one of the most prevalent and important risk factor of cardio-vascular diseases. The aim of this research was to determine relative factors on hypertension in Kohrang.
Methods: This survey was a population – based case - control study. The study population consisted of 415 patient with hypertension (cases) and 415 controls without any history of cardiovascular and or cerebrovascular diseases & hypertension. A systematic random sampling was used. The chi-square test and conditional logistic regression model was used and the data were analyzed by STATA.
Results: Family history of hypertension, age over 60, no physical activity, bmi≥30 were calculated as risk factors with odds ratio: 2.33 (95% CI 1.58-3.47), 2.01(95% CI 1.24-2.67), 1.8 (95% CI 1.2-2.7), 1.66 (95% CI 1.32-2.07) respectively (p<0.05). Fish consumption, unsaturated fat consumption and literacy were considered as protective factors with an odds ratio: 0.516 (95% CI 0.35-0.69), 0.514 (95% CI 0.36-0.72), 0.28 (95% CI 0.17-0.45) respectively (p<0.01).
Conclusions: The findings of this study highlight to plan appropriate health promotion programmes by health policy makers.
M Gholami Fesharaki , A Kazemnejad, F Zayeri, J Sanati, H Akbari,
Volume 8, Issue 4 (3-2013)
Abstract
Background and Objectives: Since there is inconsistency reports in relationship between shift work (SW) and blood pressure (BP), therefore we aimed to show any association between SW and BP by using of Bayesian Multilevel Modeling, which is a reliable method for this type of analysis.
Methods: The profiles of 4145 workers in Polydactyl Iran Corporation were examined in historical cohort between 1996 until 2008. All relevant analysis was performed by Win Bugs software.
Results: Approximately 98 percent of study population was male. Of total 1886 (45.5%), 307(7.4%), 1952 (47.1%) of participation were day worker, two rotation shift worker and three rotation shift worker respectively. After controlling confounding factors, there was no significant relationship with Systolic BP (P=0.911) and Diastolic BP (P=0.278).
Conclusion: In general, the results of our historical cohort study do not support a relationship between SW and BP. We suggest multi center and prospective cohort studies with controlling more confounding factors in this area.
N Vahabi, F Zayeri, E Fazeli Moghadam , M Safari, F Ebrahimzadeh,
Volume 11, Issue 3 (11-2015)
Abstract
Background and Objectives: Disorders of height and weight growth are the most important health disorders affecting children younger than two in developing societies. Failure to treat these disorders can lead to the increased mortality and mental, emotional or physical disability. The objective of this study was to investigate the growth trends of children and the factors affecting it.
Methods: This retrospective cohort study was conducted on 2030 children younger than two in Khorramabad, Iran who were selected using stratified and cluster sampling. Based on household records, the weight growth trend was recorded as a four-level variable (decline, stagnation, slowness and desirable) and the the height growth trend was recorded as a three-level variable (stagnation, slowness and desirable); finally, the data were modeled using a longitudinal marginal model and the SAS software version 9.2.
Results: The incidence of at least one decline in the weight growth curve and one stagnation in the height growth curve was 14.2% and 10.4%, respectively. The child’s age and the maternal educational level had a significant effect on the growth trends. However, the sex, parity and the exclusive breastfeeding during the first six months had no significant relationship with the growth trends.
Conclusion: Given the results and the relatively high prevalence of growth disorders among children, it seems that increasing the awareness of low literate women about feeding of the children is the most important approach to manage growth disorders. Additionally, health-care professionals should mostly focus on monitoring the growth of children older than 12 months.
S Abbaszadeh, Mr Baneshi, F Zolala, Y Jahani, H Sharifi,
Volume 13, Issue 3 (12-2017)
Abstract
Background and Objectives: We may sometimes measure the joint effect of correlated independent variables on several dependent variablesThe present study aimed to evaluate the performance of multivariate analysis of variance (MANOVA) and structural equation modeling (SEM) on complex relationships between variables.
Methods: The present study evaluated the knowledge and attitude of 15-18 year-old individuals towards narcotics (glass, ecstasy). The effect of independent variables on two latent variables of knowledge and attitudes was studied using SEM and MANOVA modelingThe mean square error of methods were compared.
Results: The direction of associations was similar in both methods but their coefficients and p-values were different. only the effect of gender (P-value= 0.007) on knowledge in both methods was significant. Nevertheless, gender (P-value < 0.001) and marital status (P-value< 0.001) were significantly associated with attitude in both methods. The mean square error of multivariate analysis of variance and structural equation modeling was 0.98 and 0.002 respectively.
Conclusion: In the current studythe performance of SEM was better than MANOVA. Therefore, it is suggested that SEM to be used to study the multifactorial relationship between variables. In addition, only gender was effective on knowledge in both methods, while gender and marital status were effective on attitude in both methods.
A Maghzi Najafabadi , A Hajizadeh, Sm Taghavi Shahri , Y Hajizadeh, B Mahaki,
Volume 14, Issue 2 (9-2018)
Abstract
Background and Objectives: Annually about 7 million premature deaths occur due to air pollution in the world. Nitrogen oxides are among major air pollutants. Although many foreign exposure assessment studies have been carried out, Iranian studies are limited to primary analyses. Hence, in this research, we studied spatial variation of nitrogen oxides using spatiotemporal modeling in Tehran 2014.
Methods: The concentration of nitrogen oxides was obtained from 21 air pollution monitoring stations in Tehran. There were 8760 records for each pollutant in each station. Holidays and land elevation were the predictors implemented in the spatiotemporal model. The D-STEM software was used for analyses and mapping.
Results: Nitrogen monoxide significantly decreased (P<0.001) over holidays and with an increase in land elevation (coefficient: -0.070 and -0.169, respectively). Moreover, the concentration of nitrogen dioxides decreased in holidays (coefficient: -0.630) but increased with with an increase in land elevation (coefficient: 0.155) (P<0.001).
Conclusion: Spatiotemporal exposure assessment of nitrogen oxide pollutants was done for residents of Tehran for the first time in this study. The results of this study, which are estimation maps for daily nitrogen oxides, could benefit future epidemiological studies in evaluation of the effect of air pollutions on health of Tehran citizens.
M Amini, A Kazemnejad, F Zayeri, A Amirian, N Kariman,
Volume 16, Issue 1 (6-2020)
Abstract
Background and Objectives: Gestational diabetes mellitus (GDM) is a medical problem in pregnancy, and its late diagnosis can cause adverse effects in the mother and fetus. The purpose of this research was to estimate the accuracy parameters of a biomarker for early prediction of gestational diabetes in the absence of a perfect reference standard test.
Methods: This study was conducted in 523 pregnant women who presented to Mahdieh Hospital and Taleghani Hospital affiliated with Shahid Beheshti University of Medical Sciences, Tehran, Iran 2017-2018. As a predictor for detecting GDM, beta- human chorionic gonadotropin (β-hCG) measurements were recorded during 14-17th weeks’ gestation in a checklist. The Bayesian latent variable model was used to estimate the sensitivity, specificity, and area under receiver operating characteristic curve (AUC). Bayesian parameter estimation was calculated using the R2OpenBUGS package in R version 3.5.3.
Results: The median gestational age was 33 years. In the absence of a perfect reference test, the applied model had a sensitivity, specificity, and AUC of 78% (95% credible interval (CrI): 0.66-0.83), 83% (95% CrI: 0.74-0.89), and 0.72 (95% CrI: 0.64-0.88) for β-hCG, respectively.
Conclusion: According to the results of this study, β-hCG may be an acceptable biomarker for early diagnosis of diabetes in pregnant women in the absence of a perfect reference test.
Mohammad Sasanipour, Saeedeh Shahbazin,
Volume 19, Issue 1 (6-2023)
Abstract
Background and Objectives: This research aims to investigate the components of Rowe and Kahn's successful aging model, encompassing the absence of disease and disability, high cognitive and physical performance, and active participation in life among the elderly population in Tehran in 2020, considering both genders.
Methods: This study utilized a survey approach, involving a sample of 637 individuals aged 60 years and above in Tehran. The sample was selected using a multi-stage cluster sampling method from 22 districts of Tehran, considering the elderly population in each district. Confirmatory structural equation modeling (SEM) was employed to assess whether Rowe and Kahn's model aligns with the collected data.
Results: The study's findings demonstrated that Rowe and Kahn's model exhibited a strong statistical fit (p<0.01). Factor loadings in the overall population model and among the two genders were statistically significant and varied. Across the three dimensions of successful aging (avoiding disease and disability, maintaining physical and cognitive functioning, and continuing engagement with life), avoiding disease and disability was the most strongly associated with successful aging, regardless of gender. However, in the other two dimensions, the significance and strength of participation in life and physical and cognitive function varied based on gender.
Conclusion: Programs to support the physical health of the elderly, especially in chronic diseases resulting from lifestyle choice should be developed, and increasing active participation should be a priority, which requires interventions in youth and middle age.
