Chronic Obstructive Pulmonary Disease

Background

What is COPD?

Chronic obstructive pulmonary disease (COPD) is a respiratory condition that causes breathing problems, including coughing, wheezing, shortness of breath, and mucus production. It is one of the most common chronic respiratory diseases in Canada (1), and was the third leading cause of death worldwide in 2016 (2). Smoking is the most common cause of COPD. 


Possible occupational risk factors
    • Dusts and fibres (e.g. silica, asbestos, wood, cotton, coal, grain) (3,4)
    • Fumes (e.g. welding fumes, diesel engine exhaust, asphalt fumes) (3,5)
    • Second-hand smoke (6)
    • Pesticides (7)
Key Findings

Results shown here are for working-age COPD diagnoses, which are more likely to be related to exposures at work.


Farming and food processing

Workers in these groups may be exposed to dusts (including grain dusts, and mixtures of plant, animal and microbial dusts) and pesticides, which may cause COPD. Farm workers may also be exposed to diesel engine exhaust while driving diesel-powered tractors and using other diesel-powered equipment.

    • Farm workers: 1.3 times the risk

    • Nursery and related occupations: 1.3 times the risk

    • Field crop and field crop combination farms: 1.4 times the risk

    • Other crop and livestock combination farms: 1.5 times the risk

    • Baking, confectionary making and related occupations: 1.3 times the risk

    • Feed industry: 1.4 times the risk

Textiles

The textile industry includes establishments that make yarn, cloth, cord, carpet and other textiles. Workers in these groups may be exposed to dusts (including cotton and man-made fibre dusts) which may increase the risk of COPD.

    • Textile processing occupations: 1.3 times the risk

    • Cotton yarn and cloth mills: 1.8 times the risk

    • Man-made fibre, yarn and cloth mills: 1.5 times the risk

    • Cordage and twine industries: 1.8 times the risk

    • Automobile fabric accessories industry: 1.7 times the risk

Occupations associated with exposure to wood dust

Exposure to wood dust is a possible risk factor for COPD. Workers in forestry, pulp and papermaking, and wood machining occupations may be exposed to wood dust during tasks such as cutting timber, chipping wood, processing pulp, and making wood products.

    • Timber cutting and related occupations: 1.5 times the risk

    • Labouring and other elemental work in pulp and papermaking occupations: 1.8 times the risk

    • Wood sawing and related occupations, except sawmills: 1.5 times the risk

    • Labouring and other elemental occupations in fabricating, assembling and repairing wood products: 1.5 times the risk

    • Wooden box factories: 1.9 times the risk
Construction

Workers in construction trades are exposed to several possible risk factors for COPD, including many different dusts and fibres (e.g. asbestos, silica, cement, concrete and wood dusts) and fumes (e.g. diesel exhaust, asphalt, and welding fumes). 

    • Labouring and other elemental work in excavating, grading and paving occupations: 1.8 times the risk

    • Concrete finishing and related occupations: 1.4 times the risk

    • Painters, paperhangers and related occupations: 1.6 times the risk

    • Insulating occupations: 1.8 times the risk

    • Roofing, waterproofing and related occupations: 1.6 times the risk
    • Labouring and other elemental occupations in construction trades: 1.5 times the risk

Mining

Workers in this group perform a variety of tasks including drilling and blasting, and cutting, handling and loading minerals, waste and other materials. They may be exposed to a variety of possible risk factors for COPD, including silica and diesel engine exhaust.

    • Cutting, handling and loading occupations: 1.2 times the risk

    • Labouring and other elemental occupations: 1.4 times the risk

    • Other services incidental to mining: 1.6 times the risk

    • Stone quarries: 1.8 times the risk

    • Sand pits or quarries: 1.7 times the risk
Metal processing

Metal processing workers can be exposed to metal fumes and dusts when performing tasks such as melting, heat-treating, rolling, moulding, casting, extruding, and plating metal. 

    • Metal smelting, converting and refining furnacemen: 1.3 times the risk

    • Metal rolling occupations: 1.5 times the risk

    • Moulding, coremaking and metal casting occupations: 1.3 times the risk

    • Labouring and other elemental work in metal processing occupations: 1.5 times the risk

    • Welding and flame cutting occupations: 1.2 times the risk

    • Iron foundries: 1.7 times the risk

    • Copper and copper alloy rolling, casting and extruding industries: 1.6 times the risk

Miscellaneous materials processing and manufacturing work

Workers in these occupations and industries may be exposed to several risk factors, including dusts and chemical fumes from the production of rubber or plastics, which may increase the risk of COPD.  

    • Mixing and blending occupations, chemicals and related materials: 1.6 times the risk

    • Labouring and other elemental work in chemicals, petroleum, rubber, plastic and related materials processing occupations: 1.3 times the risk

    • Bonding and cementing occupations, rubber, plastic and related products: 1.3 times the risk

    • Manufacturers of plastics and synthetic resins: 1.7 times the risk

    • Miscellaneous petroleum and coal products industries: 2 times the risk

Relative Risk by Industry and Occupation

Figure 1. Risk of COPD diagnosis among workers employed in each industry group relative to all others, Occupational Disease Surveillance System (ODSS), 2006-2016

The hazard ratio is an estimate of the average time to diagnosis among workers in each industry/occupation group divided by that in all others during the study period. Hazard ratios above 1.00 indicate a greater risk of disease in a given group compared to all others. Estimates are adjusted for birth year and sex. The width of the 95% Confidence Interval (CI) is based on the number of cases in each group (more cases narrows the interval).

 

Figure 2. Risk of COPD diagnosis among workers employed in each occupation group relative to all others, Occupational Disease Surveillance System (ODSS), 2006-2016 

The hazard ratio is an estimate of the average time to diagnosis among workers in each industry/occupation group divided by that in all others during the study period. Hazard ratios above 1.00 indicate a greater risk of disease in a given group compared to all others. Estimates are adjusted for birth year and sex. The width of the 95% Confidence Interval (CI) is based on the number of cases in each group (more cases narrows the interval).

Table of Results

Table 1. Surveillance of COPD: Number of cases, workers employed, and hazard ratios in each industry (SIC)

SIC Code * Industry Group Number of cases Number of workers employed Hazard Ratio
(95% CI) †
1 Agriculture 626 22,674 1.30
(1.20-1.41)
2/3 Forestry, Fishing and
Trapping
209 6,348 1.19
(1.04-1.36)
4 Mines, Quarries and
Oil Wells
523 13,645 1.24
(1.13-1.35)
5 Manufacturing 13,847 465,288 1.13
(1.10-1.15)
6 Construction 4,077 139,164

1.27
(1.23-1.31)

7 Transportation, Communication
and Other Utilities
4,189 138,551 1.14
(1.10-1.17)
8 Trade 7,319 290,583 1.10
(1.07-1.12)
9 Finance, Insurance and
Real Estate
445 15,233 1.10
(1.00-1.20)
10 Community, Business and
Personal Service
9,345 385,301 1.00
(0.97-1.02)
11 Public Administration and
Defense
3,034 128,185 0.84
(0.81-0.87)
         
* SIC: Standard Industrial Classification (1970)
† Hazard rate in each group relative to all others

 

Table 2. Surveillance of COPD: Number of cases, workers employed, and hazard ratios in each occupation (CCDO) group

CCDO Code * Occupation Group Number of cases Number of workers employed Hazard Ratio
(95% CI) †
11 Managerial, administrative
and related
395 23,072 0.65
(0.59-0.71)
21 Natural sciences, engineering
and mathematics
370 19,193 0.73
(0.65-0.80)
23 Social sciences and
related fields
473 21,638 0.95
(0.86-1.04)
25 Religion <5 85
27 Teaching and related 370 36,255 0.36
(0.32-0.40)
31 Medicine and health 1,969 91,413 0.77
(0.73-0.81)
33 Artistic, literary,
recreational and related
188 9,578 0.90
(0.78-1.04)
41 Clerical and related 3,576 135,172 1.00
(0.97-1.04)
51 Sales 2,111 95,469 1.00
(0.96-1.05)
61 Service 6,266 232,171 1.14
(1.11-1.17)
71 Farming, horticultural
and animal husbandry
848 32,220 1.25
(1.17-1.34)
73 Fishing, hunting,
trapping and related
15 361 1.62
(0.97-2.68)
75 Forestry and logging 216 6,277 1.29
(1.13-1.47)
77 Mining and quarrying,
including oil and gas field
283 7,637 1.20
(1.07-1.35)
81 Processing
(mineral, metal, chemical)
1,885 57,288 1.26
(1.21-1.32)
82 Processing
(food, wood, textile)
1,975 67,825 1.16
(1.11-1.21)
83 Machining and related 4,165 135,556 1.13
(1.09-1.17)
85 Product fabricating,
assembling and repairing
6,725 229,796 1.05
(1.02-1.08)
87 Construction trades 4,183 143,233 1.16
(1.12-1.20)
91 Transport equipment
operating
4,262 120,666 1.35
(1.31-1.39)
93 Materials handling and related,
not elsewhere classified
3,411 106,850 1.32
(1.27-1.36)
95 Other crafts and
equipment operating
642 19,408 1.13
(1.05-1.22)
99 Other occupations not elsewhere classified 4,588 147,549 1.34
(1.30-1.38)
         
* CCDO: Canadian Classification Dictionary of Occupations (1971)
† Hazard rate in each group relative to all others

Please note that ODSS results shown here may differ from those previously published or presented. This may occur due to changes in case definitions, methodological approaches, and the ongoing nature of the surveillance cohort.

References

  1. Public Health Agency of Canada. Asthma and Chronic Obstructive Pulmonary Disease (COPD) in Canada, 2018: Report from the Canadian Chronic Disease Surveillance System (2018)
  2. World Health Organization. The top 10 causes of death (2018)
  3. Bergdahl IA, Toren K, Eriksson K, Hedlund U, Nilsson T, Flodin R, Järvholm B. Increased mortality in COPD among construction workers exposed to inorganic dust. European Respiratory Journal. 2004;23(3):402-6.
  4. Omland O, Würtz ET, Aasen TB, Blanc P, Brisman JB, Miller MR, Pedersen OF, Schlünssen V, Sigsgaard T, Ulrik CS, Viskum S. Occupational chronic obstructive pulmonary disease A systematic literature review. Scand J Work Environ Health 2014;40(1):19-35.
  5. Hart JE, Eisen EA, Laden F. Occupational diesel exhaust exposure as a risk factor for chronic obstructive pulmonary disease. Curr Opin Pulm Med 2012;18(2):151-4.
  6. Public Health Agency of Canada. Chronic obstructive pulmonary disease (COPD) (2019) 
  7. Lytras T, Kogevinas M, Kromhout H, Carsin AE, Antó JM, Bentouhami H, Weyler J, Heinrich J, Nowak D, Urrutia I, Martinez-Moratalla J. Occupational exposures and 20-year incidence of COPD: the European Community Respiratory Health Survey. Thorax. 2018;73(11):1008-15.