Arsenic, lead, mercury and cadmium exposure and glycemic and lipid profile markers: protocol for a systematic review and meta-analysis
Toxic elements; Glycemic Control; Disorders of Lipid Metabolism
Contamination by toxic elements, including arsenic (As), lead (Pb), mercury (Hg), and cadmium (Cd), presents a global issue associated with adverse effects on human health, potentially leading to metabolic changes. However, understanding the impact of toxic element exposure on glycemic and lipid profiles remains incomplete. Given the existing controversies, the development of a systematic review is a strategy to analyze secondary data concerning the relationship between exposure to As, Pb, Hg, and Cd and the regulation of glycemic and lipid profiles. Therefore, we have devised a protocol following the PRISMA-P guidelines and registered it with PROSPERO (CRD42023393681) to evaluate environmental exposure to As, Pb, Hg, and Cd in individuals and elucidate their association with glycemic markers, such as fasting plasma glucose and glycated hemoglobin, as well as lipid parameters, including total cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein. Observational studies involving individuals aged 10 years or older will be included, with fasting blood glucose and low-density lipoprotein levels as primary outcomes. Secondary outcomes encompass oral glucose tolerance tests, insulin resistance markers, glycated hemoglobin, total cholesterol, high-density lipoprotein cholesterol, and triglycerides. Articles published in MEDLINE (PubMed), EMBASE, Web of Science, LILACS, and Google Scholar up to march 2024, and without language restrictions, will be considered. Two reviewers will independently conduct the search and selection of articles, data extraction, and quality analysis. The risk of bias and methodological quality of the included studies will be assessed using the modified Newcastle–Ottawa scale (NOS). The results will be presented as a narrative synthesis. Additionally, if a sufficient number of studies or data are collected, a meta-analysis will be performed.