Chronic obstructive pulmonary disease (COPD), is an umbrella term for progressive, long-latency lung disorders, namely emphysema, chronic bronchitis and asthma (as long as there is some degree of chronic airway obstruction).
[Source: Wikimedia Commons – National Heart Lung and Blood Institute (12 November 2013): ‘Figure A shows the location of the lungs and airways in the body. The inset image shows a detailed cross-section of the bronchioles and alveoli. Figure B shows lungs damaged by COPD. The inset image shows a detailed cross-section of the damaged bronchioles and alveolar walls’.]
The latest statistics on COPD, collated by the Health and Safety Executive (HSE), suggest that around 15% of fatal cases (around 4,000 per year), in the UK, are caused by occupational exposure to dusts (cotton, grain, endotoxin, flour, man-made vitreous fibres, silica, wood), welding fumes and chemicals (isocyanates, cadmium, vanadium, and polycyclic aromatic hydrocarbons).
Cigarette smoking, environmental pollution and genetic predisposition are the suspected cause of the residual 85% of cases.
In respect of occupational disease risk in the UK, COPD incidence rates have been found to be significantly higher (by at least 50%), compared to the national workforce as a whole, among:
- Seafarers (and other boat operatives);
- Coal mine operatives;
- Industrial cleaners;
- Packers/bottlers/canners/fillers; and
Physical contact with causative substances need not only involve primary exposure, however.
Take the National Health Service (NHS) and private medical sector, for instance, which may be putting practitioners (e.g. nurses) at risk of secondary exposure to chemical agents, used by domestic cleaners (in wards), as well as primary exposure to disinfectants when sterilising medical instruments.
We reported on the link between disinfectant exposure and COPD incidence, among 55,185 American nurses, in edition 201 of BC Disease News (here).
Dumas et al. (2017) found that those who used chemical agents to clean surfaces ‘regularly’ (at least once a week) had a 22% increased risk of developing COPD.
When results were divulged at the 2017 European Respiratory Society International Congress, study authors emphasised the need to ‘investigate the impact on COPD of lifetime occupational exposure to chemicals and clarify the role of each specific disinfectant’.
Earlier this month, lead author, Dr. Orianne Dumas, of the French Institute of Health and Medical Research (Inserm), published a supplementary study in the Journal of the American Medical Association – this is believed to be the ‘largest’ of its kind to-date.
Relevant data was pooled from the same prospective cohort of 116,429 registered nurses (The Nurses’ Health Study II), of which 73,262 were included in the present analysis.
Of these 73,262 participants, 22.9% (16,786) reported ‘regular’ (weekly) use of disinfectants to clean surfaces, while 19.0% (13,899) reported ‘regular’ use of disinfectants to clean medical instruments.
After 6 years of follow-up, between 2009 and 2015, 582 nurses had been diagnosed with COPD. Between 40% and 70% of these workers had a maximum life expectancy of 5-years post-diagnosis.
Ultimately, findings demonstrated that weekly-use of disinfectants for cleaning surfaces and medical instruments increased the risk of COPD by 38% and 31%, respectively.
Evolving from previous investigations, researchers from the University de Versailles and Harvard University, on this occasion, also monitored ‘exposure to specific chemicals’ in disinfectants, called volatile organic compounds (VOC).
Superveniently, it was identified that exposure to glutaraldehyde (commonly used for high-level disinfection), hypochlorite (chlorine-based) bleach, hydrogen peroxide, alcohol and quaternary ammonium compounds (commonly used for low-level disinfection), all of which have been described as ‘airway irritants’, were adversely associated with a 25% (glutaraldehyde) to 36% (hypochlorite bleach) increase in risk of COPD.
What is more, combined VOC exposure (specifically bleach or hydrogen peroxide exposure, in addition to aldehyde exposure) further increased COPD risk.
It was therefore concluded that:
‘… there is a biological plausibility that long-term exposure to irritant disinfectants and cleaning agents could contribute to persistent airway damage and COPD pathogenesis’.
Oxidative stress (cellular damage that can cause inflammation) is ‘now recognised’ as having an important role in the development of COPD and since most COPD patients present with neutrophilic (immune cell) inflammation, a possible metabolic pathway has been identified, which requires further investigation to better establish a ‘causal link’.
Interestingly, exposure to enzymatic cleaners, which contain ‘good’ bacteria and are principally used to clean fat and oil, as well as to eliminate unpleasant odours (e.g. urine), were not associated with COPD. There was also no statistically significant association between formaldehyde exposure and COPD incidence. The results of this investigation appeared to contravene previous studies that associated exposure with asthma outcomes.
In respect of subsequent investigations, Dr. Dumas has put forward an expanded list of VOC exposure, encompassing less common cleaning products (e.g. ortho-phthalaldehyde, peracetic acid, acetic acid, ammonia, phenolics, ethylene oxide and chloramine-T). Do these also carry a heightened risk of COPD? If so, can emerging non-chemical disinfectant technologies (e.g. steam and ultraviolet light) and ‘green cleaning’ provide the answer to this emerging occupational and public health risk?
 Hutchings S et al., 410 Estimating the Burden of occupational Chronic Obstructive Disease (COPD) in the UK. Occup Environ Med. 2017; 70:A141 <https://oem.bmj.com/content/oemed/70/Suppl_1/A141.1.full.pdf> accessed 29 October 2019.
 MRC Institute for Environment and Health (2005). Review of literature on chronic bronchitis and
emphysema and occupational exposure. Leicester, UK
 De Matteis S et al., Occupations associated with COPD risk in the large population-based UK biobank cohort study. Occup Environ Med. 2016 Jun;73(6):378-84 <https://oem.bmj.com/content/73/6/378.long> accessed 29 October 2019.
Svanes Ø et al., Respiratory health in cleaners in Northern Europe: is susceptibility established in early life? PLoS One. 2015;10(7):e0131959. <https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0131959&type=printable> accessed 1 November 2019.
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 Natalie Rahhal, ‘Cleaning supplies may raise risks for lung diseases by up to 38%, suggests study of nurses who suffer higher rates of COPD’ (18 October 2019 The Daily Mail) <https://www.dailymail.co.uk/health/article-7588647/Cleaning-supplies-raise-risks-lung-diseases-38-study-suggests.html> accessed 29 October 2019.
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 Quinot C et al., Development of a job-task-exposure matrix to assess occupational exposure to disinfectants among US nurses. Occup Environ Med. 2017;74(2):130-137. <https://oem.bmj.com/content/74/2/130.long#> accessed 1 November 2019.