Iranian Journal of

Background and Objective: This study aimed to evaluate the correlation between climatic parameters and air pollution with cardiovascular disease and its associated death during 2014 in Mashhad by time series model.
Materials and Methods: Patient data (including outpatient and hospitalization) and cardiovascular mortality were obtained from the emergency medical center and Ferdowsi organization of Mashhad. Climatic parameters such as temperature, pressure, relative humidity, wind speed, and rainfall were gathered from meteorological organization. Air pollutants data were collected from Mashhad environmental pollutants monitoring center for the statistical period of 2014-2015. In this study, Jenkins Box time series model (combined model of autoregression and moving average known as ARIMA) with significance level of 5% was used to investigate the effect of climatic parameters and air pollution values on cardiovascular disease and daily, weekly and monthly excess mortality rate. Then, the effect of various seasons on the total number of patients with cardiac issues and the resulting death was investigated by Kruskal-Wallis nonparametric test.
Results: The final model for determination of monthly correlation between climatic elements and air pollutants with the number of cardiovascular patients and its corresponding death was found to be best fitted by ARIMA (0,0,0). The monthly survey revealed that humidity (positive correlation), temperature (positive correlation), wind speed (negative correlation), and PM_2.5 (negative correlation) with average values of 16.2471, 48.1628, 122.38, and 7.3905, respectively, had significant effects on the number of people experiencing cardiovascular disease. However, the monthly survey of mortality rate due to cardiovascular disease exhibited significant correlation (p < 0.05) with pressure (positive correlation), temperature (negative correlation), and rainfall (negative correlation) with average values of 6.5904, 1.5728, and 1.1704, respectively. The results showed a significant difference between the numbers of patients experiencing cardiovascular diseases in different seasons of the year with the highest recorded number of 3778 in autumn.
Conclusion:  The results suggest moderate correlation between atmospheric elements and air pollutants with the numbers of people experiencing cardiovascular diseases in short periods; however, in the case of long-term mortality, the correlation was strong. This study showed that climatic elements and air pollutants effectively affect cardiovascular diseases, while only climatic elements played a significant role in mortality. The main challenge of the present study is that cardiovascular disease and its resulting death may be influenced by parameters other than those considered in this study, such as multiple individual and environmental confounding variables.

Background and Objective: Understanding the factors contributing to the mortality of COVID-19 patients can provide comprehensive information for preventive decisions and public health, and will help in better management of the epidemic. In this regard, the present study was conducted with the aim of identifying and introducing risk factors affecting the mortality of COVID-19 patients by modifiable and non-modifiable factors.
Materials and Methods: In this review study, according to the objectives of the study, related papers on risk factors affecting the mortality of COVID-19 patients were searched and collected in the international databases of Web of Science, Scopus, Embase, PubMed, and Google scholar. Then the results were extracted and reported by modifiable and non-modifiable factors.
Results: The results showed that almost all studies conducted in this field address non-modifiable risk factors such as age, sex, and underlying diseases including cardiovascular disease, diabetes, hypertension, respiratory diseases, cancer, self-diseases, autoimmune, and neurological diseases. Although few studies have been conducted on modifiable risk factors, lack of early admission or long waiting for hospital admission, occupancy of hospital beds and ICUs, as well as lack of equipment in hospitals were associated with increased mortality in these studies.
Conclusion: Regarding the situation of different countries in this epidemic, improving the control of the COVID-19 epidemic and reduce the mortality rate is possible by considering modifiable factors and taking appropriate measures. According to the results of studies, allocating sufficient financial, personnel and equipment resources can be effective in reducing COVID-19 mortality. However, controlling the COVID-19 epidemic to reduce morbidity and mortality as well as its economic and social consequences is possible by integrated management in the country. Also, using the experiences and guidance of the World Health Organization and successful countries, and stability in measures with a comprehensive approach should be considered.

Background and Objective: In this research, considering the importance of the adverse effects of the Covid-19 disease and identifying the environmental factors involved in its outbreak, the effects of environmental factors and compliance with health guidelines on outbreak and mortality of Covid-19 have been evaluated.
Materials and Methods: This research was a descriptive-analytical study on confirmed patients with Covid-19 in Alborz province in 2019. In this study, outbreak rate and death due to Covid-19, compliance with health guidelines, air pollutants concentrations, air pollution indicators, and the meteorological conditions of Alborz province were daily collected for 2019. All data were analyzed in IBM SPSS Statistics v26 software with Pearson, Spearman, Kruskal-Wallis, one-way variance ANOVA analysis tests, and negative binomial regression statistical models.
Results: The results of the regression model showed that in the mortality rate due to Covid-19, the variables of average temperature(p=0.042), humidity(p=0.048), rate of Covid-19 infection(p=0.001), and compliance with health guidelines(p=0.007) are significant. However, in the model of the rate of infection with Covid-19, only compliance with health guidelines(p=0.001) was significant. Pearson's and Spearman's correlation coefficients for infection rate, compliance with health guidelines, wind speed, and concentrations of carbon monoxide, PM_2.5, and SO₂ with the death rate due to corona, were 0.575, -0.411, -0.206, 0.211, 0.114 and -0.158.
Conclusion: The results showed that in addition to compliance with health guidelines, some atmospheric factors and air pollutants also impact the rate of infection and mortality caused by Covid-19.