The global prevalence of ADHD in children and adolescents: a systematic review and meta-analysis.

BACKGROUND: Attention-Deficit / Hyperactivity Disorder is a developmental neurological disorder that has three basic characteristics: Attention Deficit, Hyperactivity, and impulsivity. This study aimed to investigate the prevalence of ADHD in children and adolescents. METHODS: This investigation was carried out using the meta-analysis method under PRISMA guidelines. Until October 2020, the articles were gathered by scanning PubMed, Scopus, WOS, and Science Direct databases. The second version of Comprehensive Meta-Analysis software was used to run analyses after extracting data from chosen papers. At a significance level of 0.05, the I2 test was used to analyze study heterogeneity, and the Egger test was used to assess publication bias. RESULTS: This analysis includes 61 cross-sectional research, with 53 research used to determine the prevalence of ADHD in children, 7.6% of 96,907 children aged 3 to 12 years had ADHD (95% confidence interval: 6.1-9.4%), and 5.6% of teenagers aged 12 to 18 years have ADHD (95% confidence interval: 4.8-7%). The prevalence of ADHD in children and adolescents according to the DSM-V criterion is also higher than previous diagnostic criteria, according to studies. CONCLUSION: The findings of this study based on meta-analysis show the high prevalence of attention deficit hyperactivity disorder (ADHD). The findings of this study demonstrate the importance of management and policy in the treatment and control of ADHD in children and adolescents.

The global prevalence of primary central nervous system tumors: a systematic review and meta-analysis.

BACKGROUND: Primary central nervous system (CNS) tumors are a heterogeneous group of neoplasms, including benign and malignant tumors. Since there are many heterogeneities in the prevalence reported in previous studies on this type of tumor, this study was performed to determine the overall prevalence of different primary CNS tumors. METHOD: The study was conducted as a systematic review and meta-analysis by searching international databases, including PubMed, Scopus, Science Direct, Web of science, and the Google Scholar search engine until August 2020. After transferring the studies to information management software (EndNote) and eliminating duplicate studies, the remaining studies were reviewed based on inclusion and exclusion criteria according to three stages of primary and secondary evaluation and qualitative evaluation. Comprehensive Meta-Analysis software, Begg, Mazumdar, and I2 tests were used for data analysis, publication bias analysis, and heterogeneity analysis, respectively. RESULTS: After performing the systematic review steps, 80 studies were included for final analysis. Based on 8 studies, the prevalence of brain tumors was 70.9%. Also, studies on 7 other studies showed that the prevalence of spinal tumors was 12.2%. A review of 14 studies showed that the prevalence of neuroepithelial tumors was 34.7%. The analysis of 27 studies reported a prevalence of glioma tumors of 42.8%. Analyses performed on other studies showed that the prevalence of pituitary adenomas was 12.2%, embryonal tumors 3.1%, ependymal tumors 3.2%, meningiomas 24.1%, glial tumors 0.8%, astrocytic 20.3%, oligodendroglial 3.9%, glioblastoma 17.7%, schwannoma 6.7%, medulloblastoma 7.7% and Polycystic astrocytomas 3.8%. CONCLUSION: As a result, it can be stated that brain tumors are the most common type of primary CNS tumors. It was also observed that tumors involving neuroepithelial cells are more common in patients than other types of tumors.