Occupational allergy: respiratory hazards in healthcare workers

Cleaning products: Their chemistry, effects on indoor air quality, and implications for human health

The use of cleaning and disinfecting products both at work and at home increased during the COVID-19 pandemic. Those products often include surfactants, acids/bases, carcinogens such as chloroform, and endocrine-disrupting chemicals, such as cyclosiloxanes, phthalates, and synthetic fragrances, which may cause harmful health effects among professional cleaners as well as among people exposed at home or in their workplaces. The aim of this study was to synthesize the effects of the commonly used chemical, surface cleaning and disinfecting products on indoor air quality, focusing on chemical and particulate matter pollutants, exposure, and human health in residential and public buildings. We also provide a summary of recommendations to avoid harmful exposure and suggest future research directions. PubMed, Google Scholar, Scopus, and Web of Science (WoS) were used to search the literature. Analysis of the literature revealed that the use of cleaning products and disinfectants increase occupants' exposure to a variety of harmful chemical air contaminants and to particulate matter. Occupational exposure to cleaning and disinfectant products has been linked to an increased risk of asthma and rhinitis. Residential exposure to cleaning products has been shown to have an adverse effect on respiratory health, particularly on asthma onset, and on the occurrence of asthma(-like) symptoms among children and adults. Efforts to reduce occupants' exposure to cleaning chemicals will require lowering the content of hazardous substances in cleaning products and improving ventilation during and after cleaning. Experimentally examined, best cleaning practices as well as careful selection of cleaning products can minimize the burden of harmful air pollutant exposure indoors. In addition, indirect ways to reduce exposure include increasing people's awareness of the harmfulness of cleaning chemicals and of safe cleaning practices, as well as clear labelling of cleaning and disinfecting products.

Occupational use of high-level disinfectants and asthma incidence in early- to mid-career female nurses: a prospective cohort study

OBJECTIVES

Occupational use of disinfectants among healthcare workers has been associated with asthma. However, most studies are cross-sectional, and longitudinal studies are not entirely consistent. To limit the healthy worker effect, it is important to conduct studies among early- to mid-career workers. We investigated the prospective association between use of disinfectants and asthma incidence in a large cohort of early- to mid-career female nurses.

METHODS

The Nurses' Health Study 3 is an ongoing, prospective, internet-based cohort of female nurses in the USA and Canada (2010-present). Analyses included 17 280 participants without a history of asthma at study entry (mean age: 34 years) and who had completed ≥1 follow-up questionnaire (sent every 6 months). Occupational use of high-level disinfectants (HLDs) was evaluated by questionnaire. We examined the association between HLD use and asthma development, adjusted for age, race, ethnicity, smoking status and body mass index.

RESULTS

During 67 392 person-years of follow-up, 391 nurses reported incident clinician-diagnosed asthma. Compared with nurses who reported ≤5 years of HLD use (89%), those with >5 years of HLD use (11%) had increased risk of incident asthma (adjusted HR (95% CI), 1.39 (1.04 to 1.86)). The risk of incident asthma was elevated but not statistically significant in those reporting >5 years of HLD use and current use of ≥2 products (1.72 (0.88 to 3.34)); asthma risk was significantly elevated in women with >5 years of HLD use but no current use (1.46 (1.00 to 2.12)).

CONCLUSIONS

Occupational use of HLDs was prospectively associated with increased asthma incidence in early- to mid-career nurses.

Chemicals inhaled from spray cleaning and disinfection products and their respiratory effects. A comprehensive review

Spray cleaning and disinfection products have been associated with adverse respiratory effects in professional cleaners and among residents doing domestic cleaning. This review combines information about use of spray products from epidemiological and clinical studies, in vivo and in vitro toxicological studies of cleaning chemicals, as well as human and field exposure studies. The most frequent chemicals in spray cleaning and disinfection products were compiled, based on registrations in the Danish Product Registry. The chemicals were divided into acids, bases, disinfectants, fragrances, organic solvents, propellants, and tensides. In addition, an assessment of selected cleaning and disinfectant chemicals in spray products was carried out. Chemicals of concern regarding respiratory effects (e.g. asthma) are corrosive chemicals such as strong acids and bases (including ammonia and hypochlorite) and quaternary ammonium compounds (QACs). However, the evidence for respiratory effects after inhalation of QACs is ambiguous. Common fragrances are generally not considered to be of concern following inhalation. Solvents including glycols and glycol ethers as well as propellants are generally weak airway irritants and not expected to induce sensitization in the airways. Mixing of certain cleaning products can produce corrosive airborne chemicals. We discuss different hypotheses for the mechanisms behind the development of respiratory effects of inhalation of chemicals in cleaning agents. An integrative assessment is needed to understand how these chemicals can cause the various respiratory effects.

Methodological evaluation of human research on asthmagenicity and occupational cleaning: a case study of quaternary ammonium compounds ("quats")

In this paper, we review methodological approaches used in studies that evaluated the association between occupational exposure to quaternary ammonium compounds (quats) and occupational asthma. This association is of interest because quats are a common active ingredient of disinfectants and have been linked to work-related asthma in some circumstances. However, any evidence-based assessment of an exposure-outcome association needs to consider both strengths and limitations of the literature. We focus on publications cited by various US and international organizations. Eighteen investigations included in the review fall into two broad categories: case reports and challenge studies of individual patients and population studies that examined the association between quats and asthma occurrence in groups of subjects. We evaluated these studies guided by questions that address whether: exposure data on specific quat(s) and other agents that may cause asthma were included, new asthma cases were differentiated from asthma exacerbation, and information on respiratory sensitivity versus irritation was given. We also assessed consistency across studies. Studies of individual patients, particularly those that provided detailed information on challenge test results, document cases of asthma induced by exposure to quats. By contrast, studies of occupational groups with the highest potential for quats exposure (e.g., cleaners and farmers) do not consistently report increased incidence of asthma due specifically to quats. The unresolved methodological issues include: poor understanding of exposure pathways considering that quats are non-volatile, lack of quantitative data allowing for identification of an asthmagenicity threshold, insufficient information on whether quats are sensitizers or act via dose-dependent irritation or some other mechanism, and inability to quantify risk of new-onset asthma attributable to quats. Another important area of uncertainty is the lack of information on the specific quats being used. There is also a lack of data capable of distinguishing the effects of quats from those of other chemical and biological workplace exposures. The current state-of-the-science does not allow a proper assessment of the potential link between quats and occupational asthma.

Association of Occupational Exposure to Disinfectants With Incidence of Chronic Obstructive Pulmonary Disease Among US Female Nurses

IMPORTANCE

Exposure to disinfectants in health care workers has been associated with respiratory health outcomes, including asthma. Despite the biological plausibility of an association between disinfectants (irritant chemicals) and risk of chronic obstructive pulmonary disease (COPD), available data are sparse.

OBJECTIVE

To investigate the association between exposure to disinfectants and COPD incidence in a large cohort of US female nurses.

DESIGN, SETTING, AND PARTICIPANTS

The Nurses' Health Study II is a US prospective cohort study of 116 429 female registered nurses from 14 US states who were enrolled in 1989 and followed up through questionnaires every 2 years since. The present study included women who were still in a nursing job and had no history of COPD in 2009, and used data from the 2009 through 2015 questionnaires. Clean and complete data used for this analysis were available in July 2018, and analyses were conducted from September 2018 through August 2019.

EXPOSURES

Occupational exposure to disinfectants, evaluated by questionnaire and a job-task-exposure matrix (JTEM).

MAIN OUTCOMES AND MEASURES

Incident physician-diagnosed COPD evaluated by questionnaire.

RESULTS

Among the 73 262 women included in the analyses, mean (SD) age at baseline was 54.7 (4.6) years and 70 311 (96.0%) were white, 1235 (1.7%) black, and 1716 (2.3%) other; and 1345 (1.8%) Hispanic, and 71 917 (98.2%) non-Hispanic. Based on 368 145 person-years of follow-up, 582 nurses reported incident physician-diagnosed COPD. Weekly use of disinfectants to clean surfaces only (16 786 [22.9%] of participants exposed) and to clean medical instruments (13 899 [19.0%] exposed) was associated with COPD incidence, with adjusted hazard ratios of 1.38 (95% CI, 1.13-1.68) for cleaning surfaces only and 1.31 (95% CI, 1.07-1.61) for cleaning medical instruments after adjustment for age, smoking (pack-years), race, ethnicity, and body mass index. High-level exposure, evaluated by the JTEM, to several specific disinfectants (ie, glutaraldehyde, bleach, hydrogen peroxide, alcohol, and quaternary ammonium compounds) was significantly associated with COPD incidence, with adjusted hazard ratios ranging from 1.25 (95% CI, 1.04-1.51) to 1.36 (95% CI, 1.13-1.64). Associations were not modified by smoking or asthma status (P for interaction > .15).

CONCLUSIONS AND RELEVANCE

These longitudinal results suggest that regular use of chemical disinfectants among nurses may be a risk factor for developing COPD. If future studies confirm these results, exposure-reduction strategies that are compatible with infection control in health care settings should be developed.

Exposures to Volatile Organic Compounds among Healthcare Workers: Modeling the Effects of Cleaning Tasks and Product Use

Objectives

Use of cleaning and disinfecting products is associated with work-related asthma among healthcare workers, but the specific levels and factors that affect exposures remain unclear. The objective of this study was to evaluate the determinants of selected volatile organic compound (VOC) exposures in healthcare settings.

Methods

Personal and mobile-area air measurements (n = 143) from 100 healthcare workers at four hospitals were used to model the determinants of ethanol, acetone, 2-propanol, d-limonene, α-pinene, and chloroform exposures. Hierarchical cluster analysis was conducted to partition workers into groups with similar cleaning task/product-use profiles. Linear mixed-effect regression models using log-transformed VOC measurements were applied to evaluate the association of individual VOCs with clusters of task/product use, industrial hygienists' grouping (IH) of tasks, grouping of product application, chemical ingredients of the cleaning products used, amount of product use, and ventilation.

Results

Cluster analysis identified eight task/product-use clusters that were distributed across multiple occupations and hospital units, with the exception of clusters consisting of housekeepers and floor strippers/waxers. Results of the mixed-effect models showed significant associations between selected VOC exposures and several clusters, combinations of IH-generated task groups and chemical ingredients, and product application groups. The patient/personal cleaning task using products containing chlorine was associated with elevated levels of personal chloroform and α-pinene exposures. Tasks associated with instrument sterilizing and disinfecting were significantly associated with personal d-limonene and 2-propanol exposures. Surface and floor cleaning and stripping tasks were predominated by housekeepers and floor strippers/waxers, and use of chlorine-, alcohol-, ethanolamine-, and quaternary ammonium compounds-based products was associated with exposures to chloroform, α-pinene, acetone, 2-propanol, or d-limonene.

Conclusions

Healthcare workers are exposed to a variety of chemicals that vary with tasks and ingredients of products used during cleaning and disinfecting. The combination of product ingredients with cleaning and disinfecting tasks were associated with specific VOCs. Exposure modules for questionnaires used in epidemiologic studies might benefit from seeking information on products used within a task context.

Clustering asthma symptoms and cleaning and disinfecting activities and evaluating their associations among healthcare workers

Asthma is a heterogeneous disease with varying severity and subtypes. Recent reviews of epidemiologic studies have identified cleaning and disinfecting activities (CDAs) as important risk factors for asthma-related outcomes among healthcare workers. However, the complexity of CDAs in healthcare settings has rarely been examined. This study utilized a complex survey dataset and data reduction approaches to identify and group healthcare workers with similar patterns of asthma symptoms, and then explored their associations with groups of participants with similar patterns of CDAs. Self-reported information on asthma symptoms/care, CDAs, demographics, smoking status, allergic status, and other characteristics were collected from 2030 healthcare workers within nine selected occupations in New York City. Hierarchical clustering was conducted to systematically group participants based on similarity of patterns of the 27 asthma symptom/care variables, and 14 product applications during CDAs, separately. Word clouds were used to visualize the complex information on the resulting clusters. The associations of asthma health clusters (HCs) with exposure clusters (ECs) were evaluated using multinomial logistic regression. Five HCs were identified (HC-1 to HC-5), labelled based on predominant features as: "no symptoms", "winter cough/phlegm", "mild asthma symptoms", "undiagnosed/untreated asthma", and "asthma attacks/exacerbations". For CDAs, five ECs were identified (EC-1 to EC-5), labelled as: "no products", "housekeeping/chlorine", "patient care", "general cleaning/laboratory", and "disinfection products". Using HC-1 and EC-1 as the reference groups, EC-2 was associated with HC-4 (odds ratio (OR) = 3.11, 95% confidence interval (95% CI) = 1.46-6.63) and HC-5 (OR = 2.71, 95% CI = 1.25-5.86). EC-3 was associated with HC-5 (OR = 2.34, 95% CI = 1.16-4.72). EC-4 was associated with HC-5 (OR = 2.35, 95% CI = 1.07-5.13). EC-5 was associated with HC-3 (OR = 1.81, 95% CI = 1.09-2.99) and HC-4 (OR = 3.42, 95% CI = 1.24-9.39). Various combinations of product applications like using alcohols, bleach, high-level disinfectants, and enzymes to disinfect instruments and clean surfaces captured by the ECs were identified as risk factors for the different asthma symptoms clusters, indicating that prevention efforts may require targeting multiple products. The associations of HCs with EC can be used to better inform prevention strategies and treatment options to avoid disease progression. This study demonstrated hierarchical clustering and word clouds were useful techniques for analyzing and visualizing a complex dataset with a large number of potentially correlated variables to generate practical information that can inform prevention activities.

Occupational exposure to disinfectants and asthma control in US nurses

Disinfectant use has been associated with adverse respiratory effects among healthcare workers. However, the specific harmful agents have not been elucidated. We examined the association between occupational exposure to disinfectants and asthma control in the Nurses' Health Study II, a large cohort of female nurses.Nurses with asthma were invited in 2014 to complete two questionnaires on their current occupation and asthma (response rate 80%). Asthma control was defined by the Asthma Control Test (ACT). Exposure to major disinfectants was evaluated by a job-task-exposure matrix (JTEM).Analyses included 4102 nurses with asthma (mean age 58 years). Asthma control was poor (ACT score 16-19) in 12% of nurses and very poor (ACT score ≤15) in 6% of nurses. Use of disinfectants to clean medical instruments (19% exposed) was associated with poorly (OR 1.37; 95% CI 1.05-1.79) and very poorly (OR 1.88, 95% CI 1.38-2.56) controlled asthma (p_trend=0.004, after adjustment for potential confounders). Using JTEM estimates, exposure to formaldehyde, glutaraldehyde, hypochlorite bleach, hydrogen peroxide and enzymatic cleaners was associated with poor asthma control (all p_trend<0.05); exposure to quaternary ammonium compounds and alcohol was not.Use of several disinfectants was associated with poor asthma control. Our findings suggest targets for future efforts to prevent worsening of asthma control in healthcare workers.

Occupational Respiratory Allergic Diseases in Healthcare Workers

Healthcare workers (HCWs) are exposed to a range of high and low molecular weight agents that are allergic sensitizers or irritants including cleaners and disinfectants, natural rubber latex, and various medications. Studies have shown that exposed HCWs are at risk for work-related rhinitis and asthma (WRA). Work-related rhinitis may precede development of WRA and should be considered as an early marker of WRA. Avoidance of causative exposures through control strategies such as elimination, substitution, engineering controls, and process modification is the preferred primary prevention strategy for preventing development of work-related allergic diseases. There is limited evidence for the effectiveness of respirators in preventing occupational asthma. If sensitizer-induced WRA is diagnosed, it is important to avoid further exposure to the causative agent, preferably by more rigorous application of exposure control strategies to the workplace. This review focuses on allergic occupational respiratory diseases in HCWs.

Work-related asthma among professional cleaning women

The job of cleaning has developed dynamically as a working service, and women constitute the majority of all professional cleaning workers. Cleaners are at an increased risk of work-related asthma (WRA). This study characterizes work-related respiratory symptoms reported by female cleaners, evaluates any associated factors of WRA, and shows diagnostic management of medical certification. The study group comprised 50 professional cleaning women referred to our Occupational Diseases Department due to suspicion of occupational asthma (OA). A questionnaire, skin prick tests, serum specific IgE antibodies, and specific inhalant challenge were performed in all of the participants. Work-related asthma was recognized in 46% of symptomatic cleaners, of whom 15 were considered as having work-exacerbated asthma (WEA) and 8 as having OA. Sensitization to latex and disinfectants played an important role as a causative agent in OA of cleaners.

Occupational health risks associated with the use of germicides in health care

Environmental surfaces have been clearly linked to transmission of key pathogens in health care facilities, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, Clostridium difficile, norovirus, and multidrug-resistant gram-negative bacilli. For this reason, routine disinfection of environmental surfaces in patient rooms is recommended. In addition, decontamination of shared medical devices between use by different patients is also recommended. Environmental surfaces and noncritical shared medical devices are decontaminated by low-level disinfectants, most commonly phenolics, quaternary ammonium compounds, improved hydrogen peroxides, and hypochlorites. Concern has been raised that the use of germicides by health care personnel may increase the risk of these persons for developing respiratory illnesses (principally asthma) and contact dermatitis. Our data demonstrate that dermatitis and respiratory symptoms (eg, asthma) as a result of chemical exposures, including low-level disinfectants, are exceedingly rare. Unprotected exposures to high-level disinfectants may cause dermatitis and respiratory symptoms. Engineering controls (eg, closed containers, adequate ventilation) and the use of personal protective equipment (eg, gloves) should be used to minimize exposure to high-level disinfectants. The scientific evidence does not support that the use of low-level disinfectants by health care personnel is an important risk for the development of asthma or contact dermatitis.

Thresholds in chemical respiratory sensitisation

There is a continuing interest in determining whether it is possible to identify thresholds for chemical allergy. Here allergic sensitisation of the respiratory tract by chemicals is considered in this context. This is an important occupational health problem, being associated with rhinitis and asthma, and in addition provides toxicologists and risk assessors with a number of challenges. In common with all forms of allergic disease chemical respiratory allergy develops in two phases. In the first (induction) phase exposure to a chemical allergen (by an appropriate route of exposure) causes immunological priming and sensitisation of the respiratory tract. The second (elicitation) phase is triggered if a sensitised subject is exposed subsequently to the same chemical allergen via inhalation. A secondary immune response will be provoked in the respiratory tract resulting in inflammation and the signs and symptoms of a respiratory hypersensitivity reaction. In this article attention has focused on the identification of threshold values during the acquisition of sensitisation. Current mechanistic understanding of allergy is such that it can be assumed that the development of sensitisation (and also the elicitation of an allergic reaction) is a threshold phenomenon; there will be levels of exposure below which sensitisation will not be acquired. That is, all immune responses, including allergic sensitisation, have threshold requirement for the availability of antigen/allergen, below which a response will fail to develop. The issue addressed here is whether there are methods available or clinical/epidemiological data that permit the identification of such thresholds. This document reviews briefly relevant human studies of occupational asthma, and experimental models that have been developed (or are being developed) for the identification and characterisation of chemical respiratory allergens. The main conclusion drawn is that although there is evidence that the acquisition of sensitisation to chemical respiratory allergens is a dose-related phenomenon, and that thresholds exist, it is frequently difficult to define accurate numerical values for threshold exposure levels. Nevertheless, based on occupational exposure data it may sometimes be possible to derive levels of exposure in the workplace, which are safe. An additional observation is the lack currently of suitable experimental methods for both routine hazard characterisation and the measurement of thresholds, and that such methods are still some way off. Given the current trajectory of toxicology, and the move towards the use of non-animal in vitro and/or in silico) methods, there is a need to consider the development of alternative approaches for the identification and characterisation of respiratory sensitisation hazards, and for risk assessment.

Is the incidence of aliphatic amine-induced occupational rhinitis and asthma underestimated?

BACKGROUND

Amines, some of which are known to cause asthma, are frequently present in the work environment, but are rarely identified as being responsible for occupational rhinitis (OR) or asthma (OA). However, amine-induced OR/OA may be underreported. To discuss this hypothesis, we report a series of patients with positive amine-specific nasal provocation test (NPT).

METHODS

Review of the medical charts of 37 patients with OR (alone or associated with asthma), submitted to a NPT with an aliphatic or alicyclic amine (except for EDTA) present in a product used at work.

RESULTS

Most patients worked in the healthcare sector or for a cleaning company. Amines were mostly present in cleaning products. Seven patients had a positive NPT. NPTs were positive for the following amines: bis(aminopropyl)laurylamine, C12-C18 alkyldimethylamine oxides, bis(2-hydroxyethyl)tallowamine oxides, 3-dimethylaminopropylamine, 2,2'-dimethyl-4,4'-methylene-bis(cyclohexylamine), lauryldimethylamine oxide. NPTs were negative for the following amines: monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, triethylamine, triethylenetetramine, aminopropyltriethoxysilane, alkylpropylenediamineguanidine acetate.

CONCLUSIONS

The frequency of amine-induced OR/OA may be underestimated, particularly when cleaning products are incriminated. Comprehensive investigation of all cases is mandatory to ensure an efficient prevention policy and consequently a good clinical and socio-occupational prognosis of occupational respiratory disease.