Face masks to prevent transmission of respiratory infections: Systematic review and meta-analysis of randomized controlled trials on face mask use

ObjectivesTo examine the use of face mask intervention in mitigating the risk of spreading respiratory infections and whether the effect of face mask intervention differs in different exposure settings and age groups.DesignSystematic review and meta-analysis. We evaluated the risk of bias using the Cochrane Risk of Bias 2 tool (ROB2).Data sourcesWe searched PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science were searched for randomized controlled trials investigating the effect of face masks on respiratory infections published between 1981 and February 9, 2022. We followed the PRISMA 2020 guidelines.Eligibility criteria for selecting studiesWe included randomized controlled trials investigating the use of face mask intervention in mitigating the risk of spreading respiratory infections across different exposure settings.ResultsWe identified 2,400 articles for screening. 18 articles passed the inclusion criteria for both evidence synthesis and meta-analysis. There were N = 189,145 individuals in the face mask intervention arm and N = 173,536 in the control arm, and the follow-up times ranged from 4 days to 19 months. Our results showed between-study heterogeneity (p < 0.0001). While there was no statistically significant association over all studies when the covariate unadjusted intervention effect estimates were used (RR = 0.977 [0.858–1.113], p = 0.728), our subgroup analyses revealed that a face mask intervention reduced respiratory infections in the adult subgroup (RR = 0.8795 [0.7861–0.9839], p = 0.0249) and in a community setting (RR = 0.890 [0.812–0.975], p = 0.0125). Furthermore, our leave-one-out analysis found that one study biased the results towards a null effect. Consequently, when using covariate adjusted odds ratio estimates to have a more precise effect estimates of the intervention effect to account for differences at the baseline, the results showed that a face mask intervention did reduce respiratory infections when the biasing study was excluded from the analysis (OR = 0.8892 [0.8061–0.9810], p = 0.0192).ConclusionOur findings support the use of face masks particularly in a community setting and for adults. We also observed substantial between-study heterogeneity and varying adherence to protocol. Notably, many studies were subject to contamination bias thus affecting the efficacy of the intervention, that is when also some controls used masks or when the intervention group did not comply with mask use leading to a downward biased effect of treatment receipt and efficacy

Essays on Empirical Political Economics

This dissertation consists of three empirical essays each focusing on a different aspect of political behavior in Finnish municipalities. The second and the third essay utilize a novel data set, namely the voting advice application data from the municipal elections. In the first paper, I investigate whether establishing an asylum center for refugees in a municipality is associated with voting result changes. My contribution is to document political reactions at immigrants at a very early stage of an immigration process. With the caveat that the statistical power is low due to the small number of asylum centers, the tentative conclusion is that there seems to be no impact on voting shares of the anti-immigration party on the municipality level or on the sub-municipality level. The results for the pro-immigrant party are less conclusive. I do not find evidence on the heterogeneous effects related to the cultural homogeneity. In the second paper, I study whether a change in the local unemployment rate is associated with changes in candidate positioning in Finnish municipal elections. I find that when the unemployment rate is higher, politicians become more willing to prioritize employment over environmental protection, which is consistent with the existence of an environmental business cycle. The results are robust to different definitions of unemployment and are not driven by any single party. In the third paper, I investigate whether there is an incumbency effect with respect to policy positions regarding the degree of redistribution or the public sector size in an regression discontinuity design set-up. I also study if tenure makes politicians choose more moderate policy positions or approach national party position averages, general regional position averages or regional party position averages. The results suggest that being in office does not change politicians' policy positions

Improved Calibration for the Analysis of Emerging Contaminants in Wastewater Using Ultra High Performance Liquid Chromatography and Time-of-Flight Mass Spectrometry

The focus of this paper is to present techniques to overcome certain difficulties in quantitative analysis with a time-of-flight mass spectrometer (TOF-MS). The method is based on conventional solid-phase extraction, followed by reversed-phase ultra high performance liquid chromatography of the extract, and mass spectrometric analysis. The target compounds included atenolol, atrazine, caffeine, carbamazepine, diclofenac, estrone, ibuprofen, naproxen, simazine, sucralose, sulfamethoxazole, and triclosan. The matrix effects caused by high concentrations of organic compounds in wastewater are especially significant in electrospray ionization mass spectroscopy. Internal-standard calibration with isotopically labeled standards corrects the results for many matrix effects, but some peculiarities were observed. The problems encountered in quantitation of carbamazepine and triclosan, due to nonlinear calibration were solved by changing the internal standard and using a narrower mass window. With simazine, the use of a quadratic calibration curve was the best solution.Peer reviewe

Muistitietotutkimus : Paikantumisia, eettisiä kysymyksiä ja tulevia suuntia

Peer reviewe

Rajoista ja niiden ylittämisestä : Lapsuus ja nuoruus muistelussa

Non peer reviewe

Approaching Localized Politics of European Memories

Peer reviewe

Face masks to prevent transmission of respiratory infections : Systematic review and meta-analysis of randomized controlled trials on face mask use

Funding Information: The Strategic Research Council, Academy of Finland, 340551, LL. The Strategic Research Council, Academy of Finland, 340539, HMO. Publisher Copyright: Copyright: © 2022 Ollila et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Objectives To examine the use of face mask intervention in mitigating the risk of spreading respiratory infections and whether the effect of face mask intervention differs in different exposure settings and age groups. Design Systematic review and meta-analysis. We evaluated the risk of bias using the Cochrane Risk of Bias 2 tool (ROB2). Data sources We searched PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science were searched for randomized controlled trials investigating the effect of face masks on respiratory infections published between 1981 and February 9, 2022. We followed the PRISMA 2020 guidelines. Eligibility criteria for selecting studies We included randomized controlled trials investigating the use of face mask intervention in mitigating the risk of spreading respiratory infections across different exposure settings. Results We identified 2,400 articles for screening. 18 articles passed the inclusion criteria for both evidence synthesis and meta-analysis. There were N = 189,145 individuals in the face mask intervention arm and N = 173,536 in the control arm, and the follow-up times ranged from 4 days to 19 months. Our results showed between-study heterogeneity (p < 0.0001). While there was no statistically significant association over all studies when the covariate unadjusted intervention effect estimates were used (RR = 0.977 [0.858–1.113], p = 0.728), our subgroup analyses revealed that a face mask intervention reduced respiratory infections in the adult subgroup (RR = 0.8795 [0.7861–0.9839], p = 0.0249) and in a community setting (RR = 0.890 [0.812–0.975], p = 0.0125). Furthermore, our leave-one-out analysis found that one study biased the results towards a null effect. Consequently, when using covariate adjusted odds ratio estimates to have a more precise effect estimates of the intervention effect to account for differences at the baseline, the results showed that a face mask intervention did reduce respiratory infections when the biasing study was excluded from the analysis (OR = 0.8892 [0.8061–0.9810], p = 0.0192). Conclusion Our findings support the use of face masks particularly in a community setting and for adults. We also observed substantial between-study heterogeneity and varying adherence to protocol. Notably, many studies were subject to contamination bias thus affecting the efficacy of the intervention, that is when also some controls used masks or when the intervention group did not comply with mask use leading to a downward biased effect of treatment receipt and efficacy.Peer reviewe

The effect of bone marrow microenvironment on the functional properties of the therapeutic bone marrow-derived cells in patients with acute myocardial infarction

<p>Abstract</p> <p>Background</p> <p>Treatment of acute myocardial infarction with stem cell transplantation has achieved beneficial effects in many clinical trials. The bone marrow microenvironment of ST-elevation myocardial infarction (STEMI) patients has never been studied even though myocardial infarction is known to cause an imbalance in the acid-base status of these patients. The aim of this study was to assess if the blood gas levels in the bone marrow of STEMI patients affect the characteristics of the bone marrow cells (BMCs) and, furthermore, do they influence the change in cardiac function after autologous BMC transplantation. The arterial, venous and bone marrow blood gas concentrations were also compared.</p> <p>Methods</p> <p>Blood gas analysis of the bone marrow aspirate and peripheral blood was performed for 27 STEMI patients receiving autologous stem cell therapy after percutaneous coronary intervention. Cells from the bone marrow aspirate were further cultured and the bone marrow mesenchymal stem cell (MSC) proliferation rate was determined by MTT assay and the MSC osteogenic differentiation capacity by alkaline phosphatase (ALP) activity assay. All the patients underwent a 2D-echocardiography at baseline and 4 months after STEMI.</p> <p>Results</p> <p>As expected, the levels of pO₂, pCO₂, base excess and HCO₃were similar in venous blood and bone marrow. Surprisingly, bone marrow showed significantly lower pH and Na⁺and elevated K⁺levels compared to arterial and venous blood. There was a positive correlation between the bone marrow pCO₂and HCO₃levels and MSC osteogenic differentiation capacity. In contrast, bone marrow pCO₂and HCO₃levels displayed a negative correlation with the proliferation rate of MSCs. Patients with the HCO₃level below the median value exhibited a more marked change in LVEF after BMC treatment than patients with HCO₃level above the median (11.13 ± 8.07% vs. 2.67 ± 11.89%, P = 0.014).</p> <p>Conclusions</p> <p>Low bone marrow pCO₂and HCO₃levels may represent the optimal environment for BMCs in terms of their efficacy in autologous stem cell therapy in STEMI patients.</p