Lung Health HazardsOf FirefightingMichael Pysklywec, MD MSc CCFP(EM) DOHS FCBOMOccupational Health Clinics for Ontario Workers McMaster University, Department of Clinical Epidemiology and Biostatistics

objectives

• Review pathophysiology of various lung diseases

• Understand the relative occurrence/burden of these lung diseases amongst firefighters

Importance of respirology issues in firefighting

• The lungs are prime route of exposure for many circumstances

• Firefighting involves a broad range of potential inhalation toxins

• Respiratory pathology is a likely consequence

• Work-relatedness of lung issues may not be recognized due to latency, varied etiologies, etc.

Respirology basics

Asthma

Fibrotic lung disease(interstitial lung disease, pneumoconiosis)

Lung cancer

mesothelioma

Acute pneumonitisInhalation exposures

Irritant reactions

Pleural plaques

COPD

rhinitis

Infectious disease

Etiology of diseases in the workplace• Deterministic: the higher the exposure, the worse the

disease

• direct effects from radiation

• hearing loss

• pneumonitis

• Stochastic: the higher the exposure, the higher the probability of disease

• Lung cancer

• Predilective: demonstrates predilection +/- dose-dependency

• Allergic conditions (asthma, dermatitis, rhinitis)

How to establish causation

• Link between Disease and Exposure

• Medical literature: often lacking

• Bradford Hill Criteria: Plausibility, animal experiment, strength, analogy,

consistency, coherence, temporality

• Literature on humans is often lacking

• Studies are difficult to do

• Typically on worker cohorts with ongoing exposures

• Difficult to predict firefighter issues

WORK-RELATED ASTHMA

What is asthma?• Chronic lung disease affecting over 3 million Canadians

• Three hallmarks:

• Reversible

• Airway inflammation (swelling)

• Airway constriction (tightening)

• Brought on and aggravated by certain triggers (family history, allergy, allergens, infections, smoking, etc.)

Epidemiology

Work-related asthma is not uncommon (10-15%) but often under-recognized

• Declining lung function amongst firefighters has been observed, but it is not consistent (Crawford, 2012)

• Association: symptoms (Ribeiro, 2009); PFT abnormality (Betchley, 1997; Miedinger, 2007; Mustajbegovic, 2001; Serra, 1996; Peters 1974)

• No association: PFTs normal (Musk, 1982; Burgess, 2004; Sparrow, 1982); respiratory mortality (Rosenstock, 1990)

• Thus, there is evidence of respiratory impairment, but results vary, with considerable variance in exposures, protective practice, etc.

Airway disease in firefighters

Asthma in firefighters

• Ribeiro et al (2009)

• Prevalence of adult-onset asthma was 9.3% amongst firefighters (20% more likely than police officers)

• Miedinger et al (2007)

• Hyperreactivity to methacholine was more than twice as common in firefighters (OR = 2.24, 95% CI = 1.12-4.48)

• Respiratory symptoms (e.g. cough, dypsnea, rhinorrhea) were consistently more common in firefighters

Spirometry

• Miedinger et al (2007)

• Studied 107 firefighters in Switzerland

• 6 had previously-diagnosed asthma

• A further 8 were found to have asthma based on symptom response and methacholine challenge testing

Asthma in Firefighters

• Reinisch et al (2001)

• Examined asthma reporting system in California

• Firefighters had the second highest reporting rates of asthma, after only cleaners

Classification

Work-related asthma (WRA)

OccupationalAsthma

Work-exacerbatedAsthma (WEA)

Sensitizer-induced(allergic)

Irritant-induced(reactive airways

dysfunction syndrome: RADS)

Work-related asthma (WRA)

OccupationalAsthma

Work-exacerbatedAsthma (WEA)

Sensitizer-induced(allergic)

Irritant-induced(reactive airways

dysfunction syndrome: RADS)

• Represents the majority of occupational asthma (>90%)

• Clinical features:• fulfils the classic criteria for an allergic response:

asthma usually occurs in a minority of those exposed asthma develops only after an initial symptom-free

period of exposure• latency period of sensitization may be weeks to many

years• Symptoms worsen at work or shortly after work• Symptoms improve when away from work (initially – if

exposure continues, improvement away may not happen)

Sensitizer-induced occupational asthma

Sensitizers• There are over 300 known sensitizers, with more every year

• high molecular weight – generally proteins e.g. latex, flour, animal dander more likely to act as antigens through an IgE

mechanism• low molecular weight – generally chemicals

e.g. isocyanates, metals pathophysiology of mechanism is not well understood

• at particular risk are those with general risk factors for asthma:• Atopy, co-existing infections

Potential sensitizers in firefighting

Difficult to typify• Formaldehyde • Metals (Cr, Ni, Pt)• Anhydrides• Isocyanates• VOC’s• ? Firehall exposures:

mold

Think about where the fire occurs – asthma causing agents in everyindustry sector

• Painting (isocyanates)

• Adhesives

• Pharmaceuticals

• Pesticides

• Bakeries (grain, flour)

• Agriculture (mushrooms, poultry, livestock)

• Polymers

21

Work-related asthma (WRA)

OccupationalAsthma

Work-exacerbatedAsthma (WEA)

Sensitizer-induced(allergic)

Irritant-induced(reactive airways

dysfunction syndrome: RADS)

Irritant-induced occupational asthma• Represents a small fraction of OA (approx. 6%)• Onset typically occurs within 24 hours of exposure to a

large quantity of a respiratory irritant. That is, unlike sensitizer-induced OA, there is typically no latency period.

• Most will recover after a toxic inhalation injury; some do not

• There is persistence of symptoms beyond 12 weeks, possibly lasting years

• Pulmonary testing shows objective evidence of asthma

• There is some evidence to suggest that chronic, low-level exposure to irritants (dusts, gases, mists, fumes, smoke) that are irritating to the respiratory tract may cause asthma (Balmes 2002)

IIA and firefighters

• Pulmonary disease and the World Trade Cener (Guidotti et al, 2011)

• Significant airway reactivity (bronchodilator response and methacholine challenge) after WTC incident

• Presumably IIA due to acute exposure

• Those arriving that day were 7.8x more likely to have hyperreactivity than those arriving at a later date

• 20% of highly exposed and 8% of moderately exposed developed persistent asthma

IIA and firefighters

• Wisnivesky et al (2011) did a cohort study on incidence of various illnesses in 9/11 rescue and recovery workers (n=27 449)

Disease 9 year incidence

Asthma 27.6%

Sinusitis 42.3%

Spirometric abnormalities 41.8%

PTSD 31.9%

• IIA is quite rare and clearly under recognized

• Firefighting theoretically should be one of the most prevalent occupations with this condition

• Be vigilant about recognizing and reporting this condition

Work-related asthma (WRA)

OccupationalAsthma

Work- exacerbated / aggravated Asthma

(WEA)

Sensitizer-induced(allergic)

Irritant-induced(reactive airways

dysfunction syndrome: RADS)

CAUSESWork-Exacerbated Asthma

(also called work-aggravated asthma)

Exposure to workplace irritants or exertion at work may aggravate pre-existing or concurrent asthma, particularly in patient who have moderate or severe asthma, or who are uncontrolled, because they are not receiving optimal treatment.

Work-exacerbated asthma represented approximately half of work-related asthma seen in a Canadian clinic studies (Tarlo, 2000).

People with pre-existing asthma are still susceptible to sensitizers in the workplace

THIS IS COMPENSABLE IN ONTARIO

Diagnosis: a multi-step process

1. DIAGNOSE ASTHMA2. SUSPECT WORK-RELATEDNESS3. DETERMINE WORK-RELATEDNESS

Spirometry 101

• Measure of airflow and volume of lungs

• Most commonly consider FEV1 and FVC

Management of WRA

The three main components of the management of WRA are:1. Treat the asthma as per the usual guidelines2. Address issues of workplace exposure3. Initiate compensation claim, if applicable

Management of WRA• OA (sensitizer-induced)

• Remove from exposure: Longer duration of exposure leads to increased risk of

permanence and increased severity of disease Workers can react to very small amounts of exposure

• Irritant induced asthma (RADS)

• Remove from work until symptoms resolve

• Return to work should be considered a trial – may react to exposures for long period (some cases up to 2 years)

• Work Exacerbated Asthma (WEA):

• Control exposure - engineering efforts, modified work

• Respirator is not a solution

Management of WRA

• Initiate a compensation claim

• Sentinel health event: consider that others may be similarly affected

• All workers need education and information about managing their asthma, recognition of triggers and what to do about them + + + support.

• Employers and workplace parties also need this information as well as support in determining how they will manage the worker and address exposure issues

COPD

COPD (chronic obstructive pulmonary disease)

• Also called emphysema, chronic bronchitis

• Similar to asthma but irreversible

• Often caused by smoking: occupational relationship is often ignored/unrecognized

• Compensated in smokers: attenuate compensation based on smoking

COPD and firefighting

• Cumulative dust exposure may cause COPD

• COPD was reported in FDNY after 9/11 (Niles 2013)

• COPD has been reported in firefighter cohorts (Almeida 2007; Guidotti 1993)

RHINITIS

Rhinitis

• Upper respiratory tract (nasal congestion, etc.)

• May be irritant or allergic

• Similar etiology as occupational asthma: may be allergy from persistent allergen exposure

• High rates of rhinitis in firefighting (Ribeiro, 2009)

• Difficult to treat: tends to be persistent, affected by many variables (seasonal, allergies, environment)

• Perhaps similar etiology to irritant-induced asthma: may be single acute exposure to high level of irritant

• RUDS: reactive upper airways dysfunction syndrome

INTERSTITIAL LUNG DISEASE

Interstitial lung disease

• Scarring of lungs (interstitium)

• Also called pneumoconiosis, pulmonary fibrosis, restrictive lung disease

• Classic work-related lung diseases: asbestosis, silicosis,

• Any adult presenting with ILD should be asked about occupational exposures

• Usually strong dose-response: higher the exposure, the more chance of disease

Interstitial lung disease and the World Trade Cener (Guidotti et al, 2011)

• Interstitial disease after WTC was rare• Little asbestos used in building• Some exposure to silica, MMVF• ? Perhaps latent period has not been reached• 4 firefighters had diffuse pulmonary fibrosis

with 2 requiring lung transplants

Sarcoidosis

• Granulomatous disease often causing lung lesions, including fibrosis, as well as other organ involvement

• Unlike other ILD, onset maybe more rapid

• Cause is unknown:

? Infectious

? Autoimmune

? beryllium

Firefighters and sarcoidosis

• Kern et al (1993): identified cluster of sarcoid patients amongst FF

• Prezant et al (1999): 21 new cases and 4 previous cases of NY FF

• Izbicki et al (2007): • after WTC, 26 NYFD developed sarcoidosis;

• 13 of these developed it within 1 year of exposure

Asbestosis

• Thought to occur from all subtypes of asbestos: fairly ubiquitous material

• Industries: construction (industrial, commercial, residential), heavy industry, trades, insulation

• Long latency (20 to 40 years)

• Typically requires persistent asbestos exposure over a long period

Other interstitial lung disease

• Hypersensitivity pneumonitis (HP)

• fibrotic lung disease from persistent organic exposure

• May be seen in agricultural workers, animal handlers, those exposed to organic waste

• Unlikely to be caused by acute, high level exposures

• Eosinophillic pneumonia

• Rom et al (2002): case report from WTC

LUNG CANCER

Lung cancer

• Attributable fraction to work: 6-29%

• Only a fraction of these are being reported in Ontario: 250 to 1200 new cases per year; 152 submitted in 2003

• Many causes: asbestos, silica, PAH’s, diesel, chromium, nickel, radon, arsenic, nitrosamines

Lung cancer and firefighting

• To be added to presumptive legislation for firefighters

• Increased rates of lung cancer in this profession: Pukkala (2014), Daniels (2014)

• Potential exposures are myriad and often hard to characterize on an individual basis

• PAHs, asbestos, diesel, silica, heavy metals, arsenic, acid mist, pesticides, etc.

• Cancer is stochastic: based on probabilities

Mesothelioma

• Almost all are work-related (95%)

• Minimal exposure seems to be able to cause disease: even brief, intermittent exposure

• Many claims are being missed (Pichora, 2009)

Infectious disease

• Rhinitis, pharyngitis, pneumonia

• Due to medical call exposure

• Typically self-limited disease, although there is rare potential for more persistent conditions (e.g. HP, SARS)

• Little literature on the matter

Acute respiratory conditions

• Potential for acute respiratory conditions

• Thermal injury

• CO exposure

• Cyanide poisoning (polymer combustion)

• Chemical pneumonitis: HCl, SO2, benzene

• Largely prevented by SCBA

Prevention

Issue of skin exposure

• While respiratory protection will mitigate most important exposure, skin/dermal exposure may be an important alternate route of exposure

• Asthma can occur from skin exposure to allergens (Redlich, 2010; Bello 2007; Petsonk 2000)

• Skin exposures make been shown to be important in firefighting (Fent 2014; Baxter 2014), including PAH exposure

Overhaul

• There is potential for respiratory exposure during overhaul

• Phoenix study examined personal and area samples in overhaul (Bolstad-Johnson et al, 2000)

• CO, formaldehyde, glutaraldehyde, acrolein were found to exceed ceiling limits

• Benzene, NO2, SO2, exceeded STEL

• Initial 10min average CO concentrations did not predict other products: should not be used as an indicator gas

Overhaul

• Burgess et al (2001) evaluated respiratory effects during overhaul

• 25 had no respiratory protection; 26 wore cartridge respirators

• Important exposures: CO, NO2, SO2, HCN, formaldehyde, HCl

• There were decreases in FEV1 and FVC and impairment in alveolar permeability (CC16)

• Changes were not prevented by cartridge respirators

• Respiratory disease in firefighters is not rare

• Entire spectrum of disease may be seen:

• Asthma, fibrosis, cancer, COPD, rhinitis

• Etiology, recognition and presentation may be unusual in your occupational group

• Brief, high-level exposures

• Unknown and varied exposures

• Surveillance is challenging

• Early recognition is important for almost all conditions

• Prevention is clearly the most important management strategy

KEY POINTS:

References / ResourcesRecommended Reading:Diagnosis and Management of Work-related Asthma: ACCP Consensus http://chestjournal.chestpubs.org/content/134/3_suppl/1S.full.html An Official ATS Proceedings: Asthma in the Workplacehttp://www.thoracic.org/statements/resources/eoh/asthma-in-the-workplace.pdf Bernstein IL, et al. Asthma in the workplace… 2006Asthmagen? UK Health and Safety Executive. 2001

http://www.hse.gov.uk/asthma/asthmagen.pdf

Recommended Clinics:Occupational Health Clinics for Ontario Workers www.ohcow.on.ca (905) 549-2552St. Mikes Department of Occupational and Environmental Health www.stmichaelshospital.com/programs/occupationalhealth (416) 864-5074

Other Ministry of Labour Health & Safety Contact Centre www.labour.gov.on.ca 1-877-202-0008

More RESOURCES Organizations

• Ontario Lung Association (OLA)

www.on.lung.ca/work-related-asthma

• OLA Provider Education Program

www.olapep.ca/wra

• Workplace Safety and Prevention Services, a partner in Health and Safety Ontario

www.wsps.ca

• Canadian Centre for Occupational Health and Safety www.ccohs.ca

With thanks to: