+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Occupational risk for Legionella infection among dental healthcare workers: meta-analysis in occupational epidemiology


      BMJ Open

      BMJ Publishing Group

      Legionella, dentist, occupational and industrial medicine, dental healthcare setting

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.



          The occupational risk for Legionella infection among dental healthcare workers (DHCWs) is conjectured because of the risk of routine inhalation of potentially contaminated aerosols produced by the dental instruments. Nevertheless, occupational epidemiology studies are contrasting. This meta-analysis assessed the level of scientific evidence regarding the relative occupational risk for Legionella infection among DHCWs.


          Literature search was performed without time and language restrictions, using broad data banks (PubMed, Scopus, Web of Science, GOOGLE Scholar) and generic keywords (‘legionella’ AND ‘dent*’). Analytical cross-sectional studies comparing prevalence of high serum Legionella antibody levels in DHCWs and occupationally unexposed individuals were considered. The relative occupational risk was assessed through prevalence ratio (PR) with 95% CI. Between-study heterogeneity was assessed (Cochran’s Q test) and was used to choose the meta-analytic method. Study quality (modified Newcastle-Ottawa Scale) and publication bias (Begg and Mazumdar’s test, Egger and colleagues’ test, trim and fill R 0 method) were assessed formally and considered for the sensitivity analysis. Sensitivity analysis to study inclusion, subgroup analyses (dental staff categories; publication year, before vs after 1998, ie, 5 years after the release by the Centers for Disease Control and Prevention of the infection control guidelines in dental healthcare setting) were performed.


          Seven studies were included (2232 DHCWs, 1172 occupationally unexposed individuals). No evidence of publication bias was detected. The pooled PR estimate was statistically non-significant at 95% level (1.7; 95% CI 0.8 to 3.2), study-quality adjustment did not change the PR considerably (PR, 1.5; 95% CI 0.5 to 4.1). PR was statistically significant before 1998 and no longer significant after 1998. Subgroup analysis according to DHCW categories was inconclusive.


          There is no scientific evidence that DHCWs are at high occupational risk. The differences between former and recent studies could be due to different characteristics of municipal water systems and the infection control guideline dissemination.

          Related collections

          Most cited references 66

          • Record: found
          • Abstract: found
          • Article: not found

          Performance of the trim and fill method in the presence of publication bias and between-study heterogeneity.

          The trim and fill method allows estimation of an adjusted meta-analysis estimate in the presence of publication bias. To date, the performance of the trim and fill method has had little assessment. In this paper, we provide a more comprehensive examination of different versions of the trim and fill method in a number of simulated meta-analysis scenarios, comparing results with those from usual unadjusted meta-analysis models and two simple alternatives, namely use of the estimate from: (i) the largest; or (ii) the most precise study in the meta-analysis. Findings suggest a great deal of variability in the performance of the different approaches. When there is large between-study heterogeneity the trim and fill method can underestimate the true positive effect when there is no publication bias. However, when publication bias is present the trim and fill method can give estimates that are less biased than the usual meta-analysis models. Although results suggest that the use of the estimate from the largest or most precise study seems a reasonable approach in the presence of publication bias, when between-study heterogeneity exists our simulations show that these estimates are quite biased. We conclude that in the presence of publication bias use of the trim and fill method can help to reduce the bias in pooled estimates, even though the performance of this method is not ideal. However, because we do not know whether funnel plot asymmetry is truly caused by publication bias, and because there is great variability in the performance of different trim and fill estimators and models in various meta-analysis scenarios, we recommend use of the trim and fill method as a form of sensitivity analysis as intended by the authors of the method. Copyright 2007 John Wiley & Sons, Ltd.
            • Record: found
            • Abstract: not found
            • Article: not found

            Spurious precision? Meta-analysis of observational studies.

              • Record: found
              • Abstract: not found
              • Article: not found

              Probable Person-to-Person Transmission of Legionnaires' Disease.


                Author and article information

                BMJ Open
                BMJ Open
                BMJ Open
                BMJ Publishing Group (BMA House, Tavistock Square, London, WC1H 9JR )
                13 July 2017
                : 7
                : 7
                departmentDepartment of Public Health and Infectious Diseases , Sapienza University of Rome , Rome, Italy
                Author notes
                [Correspondence to ] Dr Stefano Petti; stefano.petti@
                © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

                This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:

                Occupational and Environmental Medicine
                Custom metadata


                legionella, dental healthcare setting, occupational and industrial medicine, dentist


                Comment on this article