Association of indoor dampness and molds with rhinitis risk: A systematic review and meta-analysis

Background: A substantial proportion of the world's population is exposed to indoor dampness-related exposures. Since the 1990s, studies have assessed the relation between indoor dampness and mold and rhinitis, but the evidence has been inconclusive. No previous meta-analysis has been reported on this topic. Objective: We conducted a systematic review and meta-analysis of studies on the relations between indoor dampness and mold and the risk of different types of rhinitis and investigated whether these relations differ according to the type of exposure. Methods: A systematic search of the Ovid MEDLINE and EMBASE databases was conducted (1950 through August 2012), and reference lists of relevant articles were reviewed. Cross-sectional, case-control, and cohort studies in children or adults were selected according to a priori criteria and evaluated by 3 authors independently. Results: Thirty-one studies on rhinitis, allergic rhinitis (AR), or rhinoconjunctivitis were included. In meta-analyses the largest risk was observed in relation to mold odor (rhinitis: 2.18 [95% CI, 1.76-2.71]; AR: 1.87 [95% CI, 0.95-3.68]). The risk related to visible mold was also consistently increased (rhinitis: 1.82 [95% CI, 1.56-2.12]; AR: 1.51 [95% CI, 1.39-1.64]; rhinoconjunctivitis: 1.66 [95% CI, 1.27-2.18]). In addition, exposure to dampness was related to increased risk of all types of rhinitis. Conclusion: This meta-analysis provides new evidence that dampness and molds at home are determinants of rhinitis and its subcategories. The associations were strongest with mold odor, suggesting the importance of microbial causal agents. Our results provide evidence that justifies prevention and remediation of indoor dampness and mold problems, and such actions are likely to reduce rhinitis.