Is Isocyanate Exposure and Occupational Asthma Still a Major Occupational Health Concern? Systematic Literature Review

Abstract

Isocyanate, whose disease-inducing mechanism is poorly understood, with poor prognosis, is widely used. Asthma is the most frequent manifestation of prolonged exposure. We assessed the evolution of the incidence of isocyanate-induced occupational asthma over time. PubMed and Cochrane databases were systematically searched for studies published since 1990 that assessed the relationship between occupational exposure to isocyanates and asthma. We identified 39 studies: five retrospective cohort studies, seven prospective cohort studies, three of which were inception cohorts), seven observational cross-sectional studies, five literature reviews, two case series, and 13 registry studies. The incidence of occupational asthma secondary to isocyanate exposure has decreased from more than 5% in the early 1990s to 0.9% in 2017 in the United States. Despite the wide use of optimal collective and individual protection measures, the risk of occupational asthma has stabilized. Occupational asthma risk can be assessed with good sensitivity using self-questionnaires and pulmonary function tests. Occupational avoidance should be implemented as soon as possible after the first symptoms appear because the prognosis becomes increasingly poor with the persistence of exposure. It is now necessary to study specifically cutaneous sensitization to isocyanates and to define what protective equipment is effective against this mode of exposure.

Evidence of seasonal changes in airborne particulate matter concentration and occupation-specific variations in pulmonary function and haematological parameters among some workers in Enugu Southeast Nigeria: a randomized cross-sectional observational study

“…Work duration has been associated with changes in pulmonary function in woodworkers [42], automobile spray painters [43], cement workers [44] and cleaners (sweepers) [45].…”

Global patterns of asthma burden related to environmental risk factors during 1990-2019: An age-period-cohort analysis for Global Burden of Disease Study 2019

“…A review reported Scandinavian countries had higher incidence of occupational asthma than Western Europe, United States of America, South Africa, and Brazil [35]. Diisocyanates is the leading cause of occupational asthma in industrialized countries [37], and diisocyanate-related new cases of occupational asthma was estimated to be > 5000/year in the European Union [38]. We showed that people aged 60-64 years old had the highest asthma death and DALYs rate attributed to occupational asthmagens, which was similar with the previous studies [39], and asthma burden remained high after retirement, suggesting cumulative and lagged effect.…”

“…For occupational asthma death and DALYs rates, our ndings demonstrated that the period and cohort RRs showed a declining trend in all regions. Promotion of respiratory protection precautions in industry, introduction of sensitive diagnostic methods, and implementation of occupational avoidance could make conspicuous improvement, and thus lead to sharp decrease in the burden of occupational asthma [37]. In 1970, the Occupational Safety and Health Administration was introduced in the USA, and it was the rst occupational regulation.…”

“…In 1978, the European Community conducted harmonizing measures to protect workers' health, and adopted a legal framework for workplace chemicals in 1980, setting a range of indicative exposure limits [42]. These policies have also achieved some results, for example, in France, the number of cases compensated for occupational asthma fell from 142 in 1991 to 23 in 2016 [37]. Besides, Australian Aluminium Council held regular health panel meetings since 1990, educated employees about occupational asthma and conducted regular health examination to reduce asthma burden 44 .…”

Development and Characterization of Eco-Friendly Non-Isocyanate Urethane Monomer from Jatropha curcas Oil for Wood Composite Applications

“…PU is typically formed by the polycondensation reaction of di/poly-isocyanates and hydroxyl groups in di/polyol; as a result, the urethane functional group is identified in the main chain [9,10]. However, using isocyanate monomers is a non-environmentally friendly and toxic issue, causing serious environmental and human health-related problems, such as irritation of the eyes, respiratory and gastrointestinal tract, and asthma in the long term [11,12]. Therefore, the industrial interest has been shifted to the use of new biodegradable and renewable green resources as PU materials.…”