The association between ambient air pollution and pulmonary tuberculosis: a systematic review protocol

Background: There is inconclusive evidence on the association between ambient air pollution and pulmonary tuberculosis-related hospital admission and mortality. This review aims to assess if and to what extent, selected air pollutants are associated to pulmonary tuberculosis (PTB) incidence, hospital admissions and mortality. Methods: This will be a systematic review and meta-analysis of studies published in English between January 1st, 1946 and October 31st, 2020, quantitatively assessing the association between air pollutants and PTB incidence, hospital admissions and mortality. A comprehensive search strategy will be used to search the databases: Medline, Embase, Scopus and The Cochrane Library. Retrieved studies will be screened based on the set eligibility criteria and data will be extracted from eligible studies. Extracted data will be analysed on STATA version 14.0 software. Studies included will be assessed for their quality using the respective Study Quality Assessment Tools of the National Health Institute. The quality of the evidence on the study outcomes will be graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The risk of bias will be assessed using Cochrane's Risk of Bias In Non-randomized Studies-of Interventions (ROBINS-I) tool. Study characteristics, socio-demographic and clinical characteristics across eligible studies will be summarised and presented. Pooled estimates of the measures of association between air pollutants and PTB incidence, hospital admission and mortality will be obtained through random-effect meta-analyses models and the respective I-2 test statistics will be reported. Meta-regression analyses will be done in case of significant between-study heterogeneity.