ABSTRACT
Introduction: Olfactory symptoms have been reported as particular in COVID-19 patients. Objective: To synthesize and analyze the existing evidence on the monitoring loss of sense of smell and taste in COVID-19 patients, and for how long symptoms persist after the virus is no longer active in the organism. Methods: A search was implemented in PubMed, Embase, Scopus, Science Direct, and Web of Science databases. This systematic review and meta-analysis were conducted according to PRISMA, and the risk of bias was assessed through the Newcastle-Ottawa Scale. The review protocol is registered in PROSPERO. Results: Our systematic review included data from 14 articles with a total of 2143 participants. The most reported sensory symptom of COVID-19 was anosmia, which was detected in 1499 patients, being the only symptom to appear in all studies. Ageusia was detected in 595 patients, dysgeusia in 514 patients, and hyposmia in 209 patients. The studies provided the number of 729 patients with sensory symptoms during the acute COVID-19 infection of 15 days, and 1020 patients with lasting sensory symptoms, presenting sensory dysfunctions after the average latent period of 15 days of the acute COVID-19 infection. Conclusion: Evidence points to the loss or dysfunction of taste and smell as one of the symptoms of COVID-19 persisting for an average time of 15 days, with 44% of COVID-19 patients with persistent symptoms for more than 15 days. Nevertheless, most studies do not perform a follow-up with those patients. Therefore, further research on sensory symptoms and their follow-up is required.
ABSTRACT
BACKGROUND: Telomere length is a common biomarker for the cumulative effect of environmental factors on aging-related diseases, therefore an association has been hypothesized between occupational exposure to pesticides and shorter telomere length. OBJECTIVE: This study is a systematic review and meta-analysis aiming to examine the association between telomere length and occupational exposure to pesticides. METHODS: We systematically searched in SciELO, PubMed, Scopus, Embase, Cochrane, Lilacs, Science Direct, and Web of Science databases for all observational studies containing measurements of telomere length on groups occupationally exposed to pesticides. Data were synthesized through qualitative synthesis and meta-analysis. We estimated the associations between exposed and non-exposed groups by using the natural log of the response ratio (lnRR). Heterogeneity was quantified using the Cochran Q test and I2 statistics. RESULTS: Six studies were included in the qualitative synthesis and meta-analysis, with a total of 480 participants exposed to pesticides. The time of exposure evaluated 391 participants that had a range of 5 to >30 years of occupational exposure. Most studies presented shorter telomere length in the occupationally exposed group. From the six studies included in the meta-analysis, three presented telomere length measurement as a single copy gene (T/S), and three presented telomere length measurement as base pairs (bp). The statistical analysis pooled estimates (log ratio of means) of the telomere length in both measurements (T/S and bp) showed a shortening of telomere length in the exposed group when compared with the non-exposed (control) group. Two of six studies reported longer telomere length in the group exposed to pesticides. DISCUSSION: Our findings suggest an association between occupational exposure to pesticides and shorter telomere length. However, we found a small number of studies to include in our meta-analysis, being required more high-quality studies to strengthen our findings and conclusions.
