Extra-auditory effects of noise exposure in school workers and preventive measures: a systematic review

Noise is still today one of the main causes of occupational diseases; in fact, in Italy in the three-year period 2019-2022, hearing loss represented 15% of all occupational diseases recognized by the National Institute for Insurance against Accidents at Work. The extra-auditory effects related to noise exposure also require particular attention, because they can interfere with mental activities that require concentration, memory and ability to deal with complex problems, causing sleep and learning disorders. For this reason, acoustic comfort is considered a fundamental requirement for obtaining an optimal degree of well-being in closed environments. In schools, a high degree of noise pollution not only makes it difficult for students to listen and learn, but also affects school workers. The aim of this study was to perform a systematic review of international literature and analysis of the preventive measures of extra-auditory effects among school workers.

The presentation of this systematic review is in accordance with the PRISMA statement. The methodological quality of the selected studies was assessed with specific rating tools (INSA, Newcastle Ottawa Scale, JADAD, JBI scale and AMSTAR). Only publications in English were selected. No restrictions were applied for the publication type. We excluded articles not concerned with the extra-auditory effects of noise exposure in school workers and preventive measures, findings of less academic significance, editorial articles, individual contributions, and purely descriptive studies published in scientific conferences.

Online research indicated 4,363 references: PubMed (2,319), Scopus (1,615) and Cochrane Library (429) have been consulted; 30 studies were included in this review (5 narrative or systematic reviews and 25 original articles). Regarding the scores of narrative reviews, the INSA score showed an average and a median value of 6.5, thus indicating an intermediate/high quality of the studies. Regarding the scores of systematic reviews, the AMSTAR score showed an average of 6.7 and a median and a modal value of 6, thus indicating a high quality of the studies. The scores assigned to the original articles have an average and median value of 7 and a modal value of 6 and this demonstrates an intermediate/high quality of the studies.

We can assume that, as it is highlighted by this study, to date these consequences are not considered at the legislative level for the protection of exposed workers. The extra-auditory effects impacting health afterward environmental noise exposure are many and widespread. Therefore, there is a need for interventions to be carried out by institutions and that the physician of the schools, during health surveillance, investigates the effects and clinical manifestations, in order to prevent disorders and deficits highlighted by our study.