Relationship between formaldehyde exposure, respiratory irritant effects and cancers: a review of reviews

Objectives: Formaldehyde is an organic compound used in the production of resins, paper, wood plywood, solvents and cleaning products. Formaldehyde is also present when tobacco is smoked. Formaldehyde has been defined as an irritant and is classified as a human carcinogen by the International Agency for Research on Cancer. The purpose of this study was to demonstrate the following two distinct correlations: (1) the association between formaldehyde exposure and development of irritant diseases affecting the respiratory tract, mainly asthma; and (2) the association between formaldehyde exposure and development of neoplastic diseases. Study design: This was an umbrella review. Methods: A search was conducted in the three main electronic databases of scientific literature: PubMed, Scopus and Web of Science. The search included systematic reviews and meta-analyses published in the previous 10 years. Initially, titles and abstracts of retrieved articles were evaluated, then full-text as-sessments of selected articles took place. Data extraction and quality assessment were performed ac-cording to Assessing the Methodological Quality of Systematic Reviews (AMSTAR) score. Results: A total of 630 articles were initially collected. Nine articles concerning the association between formaldehyde exposure and asthma were included in the present review, and the majority of these reported good association. In addition, 27 articles investigating the association between formaldehyde exposure and neoplastic diseases were included in the review. These studies showed that nasopha-ryngeal cancer and leukaemia were the most represented neoplastic diseases; however, only a weak association was reported between formaldehyde exposure and cancer. Conclusions: Although the studies included in this review did not show a strong association between exposure to formaldehyde and irritant or neoplastic diseases, the World Health Organisation recom-mends that levels of formaldehyde do not exceed the threshold value of 0.1 mg/m3 (0.08 ppm) for a period of 30 min. It is recommended that preventive measures, such as ventilation in workplaces with high exposure to formaldehyde and environmental monitoring of formaldehyde concentrations, are implemented. (c) 2023 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study aimed to investigate the correlation between formaldehyde exposure and irritant diseases (mainly asthma) and neoplastic diseases. The results showed a strong association between formaldehyde exposure and asthma, but a weak association with cancer. Although the associations were not strong, the World Health Organisation recommends limiting formaldehyde levels to 0.1 mg/m3 (0.08 ppm).