Relationship between heavy metal concentrations and Chronic kidney disease in population of Hoveyzeh cohort study: A cross-sectional study in Iran.

BACKGROUND: Chronic kidney disease (CKD) is a multifactorial disease whose prevalence is increasing worldwide. CKD affects 700 million to 1 billion people worldwide, with a prevalence of 9.1% to 13.4%. In Iran, the reported prevalence of CKD is 15.14%, even higher than the global prevalence. Some studies introduced heavy metals as possible risk factors of CKD. We conducted the first study in Iran to examine the relationship between 10 selected urinary heavy metals and CKD in the Hovayzeh cohort study population. METHODS: In this cross-sectional study, urine samples were collected from two groups of ca ses (suffering from CKD) and controls (without CKD) with equal size (47 people each). Analysis of the 10 sellected heavy metals in the samples was conducted using inductively coupled plasma emission spectroscopy. Basic Information was obtained from the Howayizeh Cohort Study Center. The data was analyzed using SPSS-26 and Excel-2016 software. RESULTS: There were no significant differences between urinary heavy metal concentrations of case and control groups (P < 0.05). While, the concentration of As, Cr, Cu, Mn, and Ni exceeded the reference limits of Germany, Canada, England, and Belgium. Se and Cd also surpassed the reference limits of England. After adjusting for confounding variables for each µg/l increase in urinary Cd, Ni, Pb, and Se the OR of CKD increased by 20.2%, 4.8%, 3.1%, and 2.6%, respectively. Although, these relationships were not statistically significant. In addition, two groups of heavy metals had a positive and significant correlation: (1) Se, Zn, As, Cu, and Cr; (2) Pb, Cd, and As; and (3) Cd and Ni. CONCLUSION: we found no significant relationship between urinary heavy metal and CKD. However, there was significant positive correlation in some of urinary heavy metals may indicate their shared resources. Furthermore, the concentration of most heavy metals in the urine of the participants was higher than the reference limits of these metals in the urine of healthy people from other countries. Thus, the elevated levels of these metals could still pose a risk to human health. Therefore, it is necessary to conduct prospective studies with a larger sample size in this area.

The impact of COVID-19 pandemic lockdowns on air quality index: a systematic review.

During the outbreak of the novel coronavirus disease 2019 (COVID-19), many countries implemented lockdown policies to control its transmission. These restrictions provided an opportunity to rest and recover the environment. This systematic review (SR) aimed to evaluate the impact of COVID-19 lockdowns on the Air Quality Index (AQI) in countries worldwide. ScienceDirect and PubMed were searched using relevant keywords to identify studies published until March 2020. Overall, 20 studies were included in the SR based on the eligibility criteria. The results show that COVID-19-related lockdown policies positively affect AQI by restricting air-polluting activities, such as transportation, industry, and construction. However, it is important to note that these policies are ineffective in controlling sources of natural air pollution and local dust. The findings of this study emphasize the need for policymakers to approve legislation limiting the sources of air pollutants.