RESUMO
BACKGROUND: Unlike cigarette smoking, environmental tobacco smoke (ETS) has not been as well described as an environmental risk for Multiple sclerosis (MS) nor as a risk factor for disease progression. OBJECTIVE: We systematically reviewed the association between ETS and the risk of onset and/or progression of MS. METHODS: We systematically screened MedLine/PubMed, Science Direct, LILACs, and SciELO searching for publications between January 1st, 2010, and July 5, 2021, with the following keywords: "multiple sclerosis and smoking"; "multiple sclerosis and passive smoking"; "multiple sclerosis and secondhand smoking". RESULTS: Fifteen articles were included in this review, which consisted of systematic reviews with meta-analysis (N = 2), systematic reviews (N = 2), and observational studies (N = 11). Both meta-analyses reported an impact of ETS on MS onset among secondhand smokers. One of the systematic reviews selected two observational studies showing the association between ETS and MS development, and one study that did not find a significant association between ETS and the risk of MS development. The other systematic review identified selected eight articles showing a relationship between ETS and MS. Seven observational studies reported higher odds of MS onset when associated with ETS. Four observational studies did not show a relationship between ETS and MS onset or progression. CONCLUSION: Most articles showed a positive association between ETS exposure and the risk of developing MS. On the other hand, an association between ETS and a higher risk for MS progression could not be established.
ANTECEDENTES: Ao contrário do tabagismo ativo, o fumo passivo (FP) não é tão bem estabelecido como risco para o desenvolvimento de esclerose múltipla (EM) nem como um fator de risco para a progressão da doença. OBJETIVO: Revisamos sistematicamente a associação entre FP e o risco de aparecimento e/ou progressão da EM. MéTODOS: Fizemos uma triagem sistemática nas bases de dados MedLine/PubMed, Science Direct, LILACs e SciELO em busca de publicações entre 1° de janeiro de 2010 e 5 de julho de 2021 com as seguintes palavras-chave: "multiple sclerosis and smoking"; "multiple sclerosis and passive smoking"; "multiple sclerosis and secondhand smoking". RESULTADOS: Quinze artigos foram incluídos nesta revisão, que consistiu em revisões sistemáticas com metanálise (N = 2), revisões sistemáticas (N = 2) e estudos observacionais (N = 11). As metanálises relataram um impacto do FP no surgimento da EM entre fumantes passivos. Um revisão sistemática selecionou dois estudos observacionais mostrando a associação entre FP e desenvolvimento de EM, e um estudo que não encontrou associação significativa entre FP e o risco de desenvolvimento de EM. Outra revisão sistemática identificou oito artigos selecionados mostrando uma relação entre FP e EM. Sete estudos observacionais relataram maiores chances de aparecimento de EM quando associados a FP. Quatro estudos observacionais não mostraram uma relação entre FP e o desenvolvimento ou progressão da EM. CONCLUSãO: A maioria dos artigos mostrou uma associação positiva entre a exposição ao FP e o risco de desenvolver EM. Por outro lado, não foi possível estabelecer uma associação entre FP e maior risco de progressão da EM.
Assuntos
Esclerose Múltipla , Poluição por Fumaça de Tabaco , Humanos , Poluição por Fumaça de Tabaco/efeitos adversos , Revisões Sistemáticas como Assunto , Esclerose Múltipla/etiologia , Fatores de Risco , Exposição Ambiental , Estudos Observacionais como AssuntoRESUMO
The recently emerged coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, is the newest threat to human health. It has already infected more than 54.5 million people worldwide, currently leading to more than 1.3 million deaths. Although it causes a mild flu-like disease in most patients, lethality may increase to more than 20% in elderly subjects, especially in those with comorbidities, like hypertension, diabetes, or lung and cardiac disease, and the mechanisms are still elusive. Common symptoms at the onset of illness are fever, cough, myalgia or fatigue, headache, and diarrhea or constipation. Interestingly, respiratory viruses have also placed themselves as relevant agents for central nervous system (CNS) pathologies. Conversely, SARS-CoV-2 has already been detected in the cerebrospinal fluid. Here, we discuss several clinical features related to CNS infection during COVID-19. Patients may progress from headaches and migraines to encephalitis, stroke, and seizures with leptomeningitis. However, the pathway used by the virus to reach the brain is still unknown. It may infect the olfactory bulb by retrograde neuronal transportation from olfactory epithelium, or it could be transported by the blood. Either way, neurological complications of COVID-19 add greatly to the complex pathophysiology of the disease. Neurological signs and symptoms must alert physicians not only to worst outcomes but also to future possible degenerative diseases.
