Background and purpose: Hashimoto thyroiditis (HT) is the most common inflammatory autoimmune thyroid disease and also the most common cause of hypothyroidism in developed countries. There is evidence of the role of HT in developing thyroid cancers (TCs). This study investigated the association between HT and different types of TCs. Methods: Results of a comprehensive search in three major databases, as well as hand searching, were screened in title/abstract and full-text stages and the relevant data were extracted from the studies that met the inclusion criteria. Risk of bias (RoB) was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools and the meta-analysis was conducted with Comprehensive Meta-Analysis software. Results: Out of 4785 records, 50 studies were included in the systematic review, and 27 of them met the criteria for quantitative synthesis. The results indicated a significant role for HT in developing papillary TC (OR: 1.65; 95% CI: 1.04 to 2.61), medullary TC (OR: 2.70; 95% CI: 1.20 to 6.07) and lymphoma (OR:12.92; 95% CI: 2.15 to 77.63); but not anaplastic TC (OR: 1.92; 95% CI: 0.29 to 1.90) and follicular TC (OR: 0.73; 95% CI: 0.41 to 1.27). Also, this study found a significant association between HT and thyroid malignancies (OR: 1.36; 95% CI: 1.05 to 1.77). Conclusion: Although we found a significant association between HT and some types of TCs, High RoB studies, high level of heterogeneity, and the limited number of well-designed prospective studies, suggested the need for more studies to reach more reliable evidence.

Metformin is a biguanide, evolved as one of the most widely used medicines. The applications of this component include but are not limited to reducing blood glucose, weight loss, and polycystic ovary syndrome. Studies about other probable indications have emerged, indicating that this agent can also be utilized for other purposes. In this review, applications of metformin are noticed based on the current evidence. Metformin commonly is used as an off-label drug in non-alcoholic fatty liver disease (NAFLD), but it worsens inflammation and should not be used for this purpose, according to the latest research. Metformin decreased the risk of death in patients with liver cirrhosis. It is an effective agent in the prevention and improvement of survival in patients suffering hepatocellular carcinoma. There is evidence of the beneficial effects of metformin in colorectal cancer, early-stage prostate cancer, breast cancer, urothelial cancer, blood cancer, melanoma, and bone cancer, suggesting metformin as a potent anti-tumor agent. Metformin shows neuroprotective effects and provides a potential therapeutic benefit for mild cognitive impairment and Alzheimer’s disease (AD). It also has been shown to improve mental function and reduce the incidence of dementia. Another condition that metformin has been shown to slow the progression of is Duchenne muscular dystrophy. Regarding infectious diseases, tuberculosis (TB) and coronavirus disease (COVID-19) are among the conditions suggested to be affected by metformin. The beneficial effects of metformin in cardiovascular diseases were also reported in the literature. Concerning renal function, studies showed that daily oral administration of metformin could ameliorate kidney fibrosis and normalize kidney structure and function. This study reviewed the clinical and preclinical evidence about the possible benefits of metformin based on recent studies. Numerous questions like whether these probable indications of metformin can be observed in non-diabetics, need to be described by future basic experiments and clinical studies.

Attention, as it is now defined as a process matching data from the environment to the needs of the organism, is one of the main aspects of human cognitive processes. There are several aspects to attention including tonic alertness (a process of intrinsic arousal that varies by minutes to hours), phasic alertness (a process that causes a quick change in attention as a result of a brief stimulus), selective attention (a process differentiating multiple stimuli), and sustained attention (a process maintaining persistence of response and continuous effort over an extended period). Attention dysfunction is associated with multiple disorders; therefore, there has been much effort in assessing attention and its domains, resulting in a battery of tests evaluating one or several attentional domains; instances of which are the Stroop color-word test, Test of Everyday Attention, Wisconsin Card Sorting Test, and Cambridge Neuropsychological Test Automated Battery. These tests vary in terms of utilities, range of age, and domains. The role of attention in human life and the importance of assessing it merits an inclusive review of the efforts made to assess attention and the resulting tests; Here we highlight all the necessary data regarding neurophysiological tests which assess human attentive function and investigates the evolution of attention tests over time. Also, the ways of assessing the attention in untestable patients who have difficulty in reading or using a computer, along with the lack of ability to comprehend verbal instructions and executive tasks, are discussed. This review can be of help as a platform for designing new studies to researchers who are interested in working on attention and conditions causing deficits in this aspect of body function, by collecting and organizing information on its assessment.