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Article

Identification of Occupational Cancer Risks in British Columbia, Canada: A Population-Based Case—Control Study of 1,155 Cases of Colon Cancer

by
Raymond Fang
1,2,*,
Nhu Le
2 and
Pierre Band
2,3
1
American Academy of Physician Assistants, Suite 1300, 2318 Mill Road, Alexandria, VA 22314, USA
2
Cancer Control Research, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, BC V5Z 1L3, Canada
3
Health Canada, 50 Columbine Drive, Tunney’s Pasture, Ottawa, ON K1A 0K9, Canada
*
Author to whom correspondence should be addressed.
Int. J. Environ. Res. Public Health 2011, 8(10), 3821-3843; https://0-doi-org.brum.beds.ac.uk/10.3390/ijerph8103821
Submission received: 8 August 2011 / Revised: 2 September 2011 / Accepted: 19 September 2011 / Published: 26 September 2011
(This article belongs to the Special Issue Occupational Cancer)
Versions Notes

Abstract

:

Objective

Cancer has been recognized to have environmental origin, but occupational cancer risk studies have not been fully documented. The objective of this paper was to identify occupations and industries with elevated colon cancer risk based on lifetime occupational histories collected from 15,463 incident cancer cases.

Method

A group matched case-control design was used. All cases were diagnosed with histologically proven colon cancers, with cancer controls being all other cancer sites, excluding rectum, lung and unknown primary, diagnosed at the same period of time from the British Columbia Cancer Registry. Data analyses were done on all 597 Canadian standard occupation titles and 1,104 standard industry titles using conditional logistic regression for matched data sets and the likelihood ratio test.

Results

Excess colon cancer risks was observed in a number of occupations and industries, particularly those with low physical activity and those involving exposure to asbestos, wood dusts, engine exhaust and diesel engine emissions, and ammonia.

Discussion

The results of our study are in line with those from the literature and further suggest that exposure to wood dusts and to ammonia may carry an increased occupational risk of colon cancer.

1. Introduction

Colon cancer is one of the leading cancer causes of death. In Canada, colon cancer is the third most common form of cancer (after prostate cancer and lung cancer in men and breast cancer and lung cancer in women) and the third leading cancer cause of death (after lung cancer and prostate cancer in men and lung cancer and breast cancer in women) [1].
Despite the common occurrence of colon cancer, its etiology is not well established; age, family history [2], lifestyle factors [3–6] including daily alcohol use, low-fiber diets, a high consumption of animal fat and red meat, physical inactivity [7–10], obesity [11–13] and smoking [14] are reported risk factors. The evidence regarding occupational exposures related to the occurrence of colon cancer is generally limited and/or not consistent [15]. Exposures to asbestos [16,17], dyes in textile industry [18], hydrazine in rocket fuels [19], pesticides in agriculture [20], engine exhaust and diesel engine emissions [21] and occupations as managers [22], male farmers [23], painters, police, guards and firemen, motor transport workers and clerks as well as exposures in non-metallic mineral products, leather goods, meat, poultry, and fish products industries [24] have been reported to be associated with a higher risk of colon cancer. A consistent relationship, however, has primarily been found for physically inactive occupations [25–29].
We have, as part of a program aimed at detecting occupational risk factors in British Columbia, Canada, collected lifetime occupational histories from 15,463 incident cancer cases, of which 1,155 had a diagnosis of colon cancer. Occupational risks for this group of patients are presented in this article by assessing risk difference in comparison with internal controls consisting of all other cancer patients excluding lung and rectum cancer and cancer of unknown primary sites.

2. Materials and Methods

2.1. General Methodology

The general methodology of the study has been described in detail in a previous article [30]. Briefly, male cancer patients aged 20 years and older ascertained by the population-based British Columbia Cancer Registry (BCCR) for the years 1983 to 1990 inclusively, received a self-administered questionnaire requesting lifetime job descriptions, occupation and industry titles, and duration and period of work, as well as information on ethnic origin, education, and lifetime smoking habits. Questions about lifetime consumption of alcoholic beverages, which were initially omitted, were added to the questionnaire during the first year of the study. In the event of a patient’s death, information was requested from the spouse or closest living relative. For the first two years, questionnaires were sent to all cases. Data collection continued until 1,000 completed questionnaires were accrued for each tumor site, or until 31 December 1990, whichever occurred first. The distribution of patients’ usual occupations and usual industries as well as assessments of response bias and of questionnaire validation and reliability was conducted and previously reported [30]. The anatomic site and pathology of the primary tumor were coded using the 9th revision of the International Classification of Diseases [31] and the International Classification of Diseases for Oncology [32], respectively. Occupations and industries were coded according to the Canadian Standard Occupational Classification (SOC) and the Canadian Standard Industrial Classification (SIC), respectively [33,34]. In the SOC, occupations are coded according to two-digit major group codes, three-digit minor group codes, and four-digit unit group codes. In the SIC, industries are coded according to two-digit major group codes, three-digit group codes, and four-digit class codes. During the data-collection period, questionnaires were sent to all 25,726 eligible male cancer cases ascertained by the BCCR and 15,463 (60.1%) were returned. Histological confirmation of diagnosis was obtained in all cases. For colon cancer, questionnaires were sent to 1,768 eligible cases, of which 1,156 (65.4%) were returned.

2.2. Statistical Methodology

A group matched case-control design was used. Cases comprised all 1,156 colon cancer patients. Controls comprised internal controls with all other cancer sites, excluding lung cancer (n = 2,998), rectum cancer (n = 1,095) and cancers of unknown primary site (n = 708), matched to the cases on exact age and year of diagnosis. These were based on a few methodological considerations. First, using other cancers as controls has a few advantages over population controls with regard to recall and interviewer bias when using general population controls, a mixture of live and deceased controls can be expected when selecting other cancer patients as controls and there are logistical and cost advantages in using other cancer patients as controls. Thus the study design using cancers as controls is likely to be used increasingly in the future, particularly in cancer registry settings [35]. Next, since lung cancer is mainly caused by smoking, excluding it from the control group would avoid potential bias of having too many smokers in controls. In addition, matching on age and year of diagnosis is a way to control for major confounders. Including year of diagnosis is a control of time when rapid changes in population structure were happened from 1960s through 1990s.
Data were analyzed using conditional logistic regression for matched sets and the likelihood ratio test [36,37] in a two-step procedure. In step 1, the effect of the following non-occupational confounding variables was assessed: marital status; education (less than 8 years; 8 to 11 years; high school; post-secondary); smoking (starting age at smoking, average number of cigarettes, pipe or cigars smoked per day, total years smoked); alcohol consumption (starting age at consuming alcohol; average of number of bottles of beer, glasses of wine, ounces of spirits consumed per day; total years of consuming alcohol); and person who filled out the questionnaire (self or proxy). Variables were selected in a forward fashion each being examined separately; Potentially important confounders (P < 0.2) were then included in the model and the remaining ones were examined; the process was repeated until no factor with P < 0.2 was identified. In step 2, each occupation and industry was assessed separately using conditional logistic regression in which all significant confounding variables identified in step 1 were taken into account. The cut point of 0.20 was chosen in step 1 to ensure that the process has sufficient power to identify potentially important confounders.
Matched case-control analyses were carried out using PECAN software [38], test of significance of the adjusted odds ratios (ORs), p-values and 95% confidence intervals were calculated and presented. Analyses were performed for the following two different estimates of occupational exposures: ever occupation/industry (whether a job was ever held in a given occupation/industry under consideration) versus never, and usual occupation/industry (job with the longest held lifetime employment in a given occupation/industry). People in either ever or usual occupation/industry categories were always compared to their counterparts who were never in such occupation/industry. Due to all 597 occupation titles and 1,104 industry titles were analyzed and small numbers of cases in many occupation/industry categories, we intended to maximally present results of the analyses in this article with occupations and industries as long as their number of cases is five and over.

3. Results

Matching resulted in 1,155 colon cancer cases having at least one matching control and 7,552 controls, leaving an overall control to case ratio of 6.5:1. Site distribution of controls is listed in Table 1.
The characteristics of cases and controls are shown in Table 2.
Statistically significant ORs were noted for the following variables: smoking duration and education level as shown in Table 3; the latter was mainly due to the unknown category.
Odds ratios by ever and usual occupation and industry categories are shown in Tables 4 and 5, respectively. In the ever occupation/industry categories and for most major groups, a number of occupations/industries had significantly elevated ORs. In many instances, the corresponding ORs in the usual occupations/industries categories were either non-significant or had fewer than five cases. Concordance for statistically significantly increased ORs between ever and usual categories at least at significant level P = 0.10 with a minimum of five cases in each category is shown in italics below.

3.1. Usual Occupation (Table 4)

In the usual occupation category, significant excess risk in the major occupation groups (two-digit codes) was only observed at P = 0.10 for occupations in social sciences and related (SOC 23). Excess risks for minor groups (three-digit codes) were significant at P = 0.05 for occupations in fabricating, assembling and repairing wood products (SOC 854) and at P = 0.10 for occupations in other managers and administrators (SOC 113/114), bookkeeping and account-recording (SOC 413), and lodging and other accommodation services (SOC 613). Several unit occupations (four-digit codes) had significantly increased ORs at P = 0.05 for: insurance sales jobs (SOC 5171), rail transport equipment mechanics and repairers (SOC 8583), brick and stone masons-tile setters (SOC 8782), ship engineering officers (SOC 9153), and at P = 0.10 for: administrators in teaching and related fields (SOC 1133), financial management (SOC 1135), livestock farm workers (SOC 7183), sawmill sawyers and related (SOC 8231), cabinet and wood furniture makers (SOC 8541), and taxi drivers and chauffeurs (SOC 9173); the ORs were significantly low at P = 0.10 for sales clerks and salespersons in commodities, not else classified (SOC 5135) and welding and flame cutting (SOC 8335).

3.2. Usual Industry (Table 5)

In the usual industry category, a significant excess risk in the major industry group was noted at P = 0.05 for motor vehicle, parts and accessories, wholesale (SIC 55) and insurance and real estate agencies (SIC 76) and at P = 0.10 for beverage (SIC 11), federal government services (SIC 81) and membership organizations (SIC 98); ORs for printing, publishing and allied (SIC 28) industry was low at P = 0.10. Excess risks were significant at P = 0.05 for the following minor industry groups (three-digit codes): brewery products (SIC 113), defense services (SIC 811), and human resource administration (SIC 826) and at P = 0.10 for livestock farms (except animal specialties) (SIC 011), and dairy products (SIC 104). Odds ratio was significantly low at P = 0.10 for interior and finishing work (SIC 427). Several industry classes (four-digit codes) had significantly increased ORs at P = 0.05 for poultry and egg farms (SIC 0114), construction, mining machinery, materials handling (SIC 3192), exterior close-in: masonry work (SIC 4231), used goods moving and storage (SIC 4562), and specialty food stores (SIC 6012). ORs were significantly low at P = 0.10 for general freight trucking (SIC 4561), motor vehicle repair garages (general repairs) (SIC 6351) and general hospitals (SIC 8611).
In the validation study of the questionnaire, company job records of 81 individuals who reported having been employed in one of two large companies in BC were compared with information from their questionnaire; and the interclass correlation was 0.996 for starting year of employment and 0.971 for duration of employment.

4. Discussion

Significant associations between colon cancer and a number of occupations and industries were observed in our study. Several sedentary occupations in management, administration, bookkeeping and recording, financial management, insurance and real estate, and lodging and accommodation showed significantly increased risk of colon cancer either at P = 0.05 or at P = 0.10, which are consistent with findings from the previous studies [25–29].
In this study, we found some occupations and industries with significantly elevated risks of colon cancer in both ever and usual employment categories: workers working in occupations or industries with low physical activity, including insurance sales, human resource administration and membership organizations; rail transport equipment mechanics and repairers who were exposed to asbestos that has been reported to be associated with a higher risk of colon cancer; taxi drivers/chauffeurs who were exposed to engine exhaust and diesel engine emissions, a known carcinogen for colon cancer [21]; workers working in brewery products with exposure to chemicals such as ammonia refrigerant. Ammonia, potentially toxic to cells, shortens cell life span and alters DNA synthesis in various tissues including the ileum and colon [39] and is also thought to promote colon carcinogenesis in rats [40].
Elevated colon risks were also found in usual employment categories for occupations in wood products fabricating, assembling and repairing with exposure to wood dusts, a controversial agent without sufficient evidence of the association by the International Agency of Research on Cancer by far; industries of poultry and egg farms with exposure to gaseous agents such as ammonia from litter, carbon monoxide from poorly ventilated gas-fired heaters and hydrogen sulphide from liquid manure. Also, particles of organic or agricultural dust are aerosolized from poultry house litter; livestock farms (except animal specialties) and dairy products and relevant occupations with exposure to noxious gases such as hydrogen sulfide, and ammonia and methane in the ambient barn air; sawmill sawyers and workers working in motor vehicle parts and accessory wholesale and truck transportation on used goods, with exposure to engine exhaust and diesel engine emissions [21]; workers in construction, mining machinery material handling, brick and stone masons-tile setters as well as exterior close-in masonry work, with exposure to asbestos, which was widely used prior to 1978 in many building projects to increase the strength of concrete; ship engineering officers who were exposed to exhaust gases, engine emissions and asbestos; and workers in beverage industry with exposure to chemicals in gases and vapors typically involving chemical-handling activities related to cleaning operations, disinfection of process areas and use of preservatives in long-term food storage, in addition to thermal oils in the maintenance of heating and ammonia in cooling systems.
The strengths of this study are several folds. It is population-based with ascertainment of pathology confirmed cancer incident cases and includes lifetime occupational history with the ability to control for potential confounding factors and effect modifiers. Our study has revealed a number of occupational risk factors for colon cancer. Interpretation of those findings is limited by the lack of information on occupational exposures and the possibility that statistically significant results may have occurred by chance because of multiple comparisons; also, especially for many usual occupations and industries, numbers are few. In addition, other cancer cases used as controls may not be representative of the general population. Particularly, other cancers may also have some occupational risks that are common to those of colon cancer cases; in such situation, the corresponding estimated OR’s noted in this study would underestimate the true risks. A missing value category was used in the analysis to avoid reducing the study sample size and that may yield biased results. However, since the proportion of missing data is small and it is unlikely that missing information on education and smoking is correlated with job classification, the biases if any should be relatively small. Some of the confounding factors such as measures of body-mass index and physical activities were not collected for this study. Nevertheless, our validation study demonstrates that self-reported employment history bear little recall errors in out study.
Some of the risks observed may not apply to current workers because of a potential decrease in industrial exposures. However, the results of our study are in line such as elevated colon cancer risk by exposure to asbestos and to engine exhaust and diesel engine emissions from the literature and further suggest that exposure to wood dusts and to ammonia may carry an increased risk of colon cancer. More specific studies using population controls are needed to investigate associations between occupation and exposures to chemical substances, taking into account changes in concentration levels over time.

Acknowledgements

The research was partially supported by grants from the Workers’ Compensation of British Columbia and the National Health Research and Development Program, Health Canada. We gratefully acknowledge the invaluable contribution of the research assistants, Ms. Donna Kan and Ms. Barbara Jamieson. Finally, the authors would like to thank two anonymous reviewers and a guest editor who provided thoughtful and insightful comments that helped to improve this article.

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Table
Table 1. Cancer site distribution of 7,552 controls.
Table 1. Cancer site distribution of 7,552 controls.
SiteControlsPercent
lip991.3%
oral cavity3905.2%
esophagus1742.3%
stomach3434.5%
liver380.5%
pancreas1361.8%
larynx2803.7%
soft tissue sarcoma1011.3%
melanoma4586.1%
non-melanoma skin1,05013.9%
prostate1,36618.1%
testis821.1%
bladder97212.9%
kidney3144.2%
brain1592.1%
Hodgkin’s Disease520.7%
non-Hodgkin’s lymphoma4175.5%
multiple myeloma1181.6%
leukemia1842.4%
other sites3264.3%
multiple sites4936.5%
Total7,552100.0%
Table
Table 2. Characteristics of cases and controls.
Table 2. Characteristics of cases and controls.
Colon Cancer CharacteristicsCases (n = 1,155)Controls (n = 7,552)
No. (%)No. (%)
Year of diagnosis
1983218(18.9)2,674(35.4)
1984254(22.0)1,660(22.0)
1985259(22.4)1,302(17.2)
1986246(21.3)1,010(13.4)
1987178(15.4)906(12.0)
Marital Status
Single56(4.8)352(4.7)
Married/common law958(82.9)6,269(83.0)
Widowed74(6.4)463(6.1)
Separated/divorced54(4.7)405(5.4)
Not answered13(1.1)63(0.8)
Education
≤7 years136(11.8)842(11.1)
8–11 years511(44.2)3,336(44.2)
High school138(11.9)830(11.0)
Post-secondary329(28.5)2,144(28.4)
Not answered41(3.5)400(5.3)
Alcohol consumption status
Never drinker137(11.9)738(9.8)
Ever drinker890(77.1)5,456(72.2)
Not answered128(11.1)1,358(18.0)
Smoking duration, years
0282(24.4)1,501(19.9)
1–29379(32.8)2,026(26.8)
30–44284(24.6)2,216(29.3)
45+196(17.0)1,682(22.3)
Not answered14(1.2)127(1.7)
Cigarette Pack-Years
0282(24.4)1,501(19.9)
1–24348(30.1)2,039(27.0)
25–49271(23.5)2,012(26.6)
≥50200(17.3)1,582(20.9)
Unknown54(4.7)418(5.5)
Pipe smoking status
Non-Pipe Smoker1,098(95.1)7,053(93.4)
Pipe Smoker57(4.9)499(6.6)
Respondent to questionnaire
Patient930(80.5)5,955(78.9)
Proxy199(17.2)1,403(18.6)
Unknown26(2.3)194(2.6)
Table
Table 3. Odds Ratios (OR) for potentially important confounding variables/effect modifiers.
Table 3. Odds Ratios (OR) for potentially important confounding variables/effect modifiers.
Confounding VariableCasesControlsORP-value95% Confidence Interval (95% CI)
Smoking duration, years
02821,5041.00
1–293792,0261.050.600.87–1.26
30–442842,2200.69<0.010.57–0.83
45+1961,6840.57<0.010.46–0.70
Not answered141180.580.060.33–1.02
Education
≤7 years1368431.00
8–11 years5113,3390.990.920.79–1.24
High school1388301.050.720.80–1.37
Post-secondary3292,1460.980.860.78–1.23
Not answered413940.650.030.44–0.96
Table
Table 4. Odds Ratios for ever and usual occupations.
Table 4. Odds Ratios for ever and usual occupations.
CodeOccupation TitleEverUsual
CaseORP value95% CICaseORP value95% CI
11Managerial, Administrative and Related3091.120.1630.961.311731.170.1220.961.43
111Officials and Administrators Unique to Government401.190.3430.831.71171.180.5480.692.03
1113Administrators111.350.3900.682.6851.370.5390.503.74
1116Inspectors and Regulatory Officers211.170.5240.721.90111.330.4020.682.59
113/114Other Managers and Administrators1571.130.2180.931.37841.240.0990.971.58
1130General Managers and Other Senior Officials621.260.1300.931.70281.300.2260.851.99
1131Management, Natural Sciences Engineering70.750.4860.331.6961.270.6160.503.23
1133Administrators in Teaching and Related Fields171.320.3250.762.29101.960.0760.934.12
1135Financial Management271.330.1900.872.04171.590.0990.932.73
1137Sales and Advertising Management540.920.5970.681.25200.790.3310.491.29
1143Production Management310.940.7640.631.41110.960.9040.491.86
1145Management, Construction Operations90.570.1090.291.1360.930.8730.382.27
1147Management, Transport, Communication Operations251.430.1200.912.2491.050.8950.512.17
1149Other Managers and Administrators, NEC481.260.1780.901.76171.410.2080.832.41
117Occupations Related to Management/Administration681.100.5040.831.46250.870.5380.561.36
1171Accountants, Auditors and Other Financial Officers461.150.4100.831.60231.020.9340.641.63
21Natural Sciences, Engineering and Mathematics840.940.6320.731.21350.790.2100.551.14
214/215Architects, Engineers and Community Planners250.900.6420.581.40130.950.8690.521.75
216Other Occupations in Architecture and Engineering401.110.5550.791.57110.910.7810.471.77
23Social Sciences and Related191.230.4290.742.05141.740.0770.943.21
234Law and Jurisprudence101.470.2980.713.0481.560.2820.693.51
2343Lawyers and Notaries101.880.0950.903.9471.720.2210.724.10
25Religion111.050.8860.542.0591.300.5050.602.81
2511Ministers of Religion111.100.7850.562.1891.300.5050.602.81
27Teaching and Related520.880.4410.641.22240.790.3080.501.24
271University Teaching and Related121.050.8790.561.9781.080.8470.492.36
2711University Teachers100.990.9770.501.9581.180.6800.542.59
273Elementary and Secondary School Teaching280.780.2420.511.18130.700.2510.381.29
2733Secondary School Teachers140.810.4730.461.4460.690.4080.291.66
31Medicine and Health310.810.2990.541.21220.830.4360.521.33
311Health Diagnosing and Treating161.190.5350.692.06161.240.4580.702,19
3111Physicians and Surgeons121.410.2970.742.69121.190.2860.861.64
33Artistic, Literary, Recreational and Related361.020.9160.711.47151.360.2940.772.42
331Fine and Commercial Art, Photography and Related90.800.5390.391.6381.530.2900.703.36
41Clerical and Related1951.000.9120.851.21540.990.9480.731.34
413Bookkeeping, Account-recording651.080.5970.811.44201.660.0521.002.77
4130Supervisors101.090.8070.552.1852.330.1250.796.87
4131Bookkeepers and Accounting Clerks421.190.3250.841.6850.860.7610.332.28
415Material Recording, Scheduling and Distributing610.780.0750.590.03110.670.2230.351.28
4155Stock Clerks220.640.0650.401.0360.950.9100.392.31
417Reception, Information, Mail, Message Distribution280.900.6110.601.3580.720.3980.341.54
419Other Clerical and Related731.250.1001.001.61130.970.9200.541.75
51Sales2791.090.2640.941.271040.940.5850.751.17
513/514Sales, Commodities1960.980.8150.831.16700.810.1150.621.05
5130Supervisors850.850.1690.671.07350.850.3970.581.24
5133Commercial Travellers491.250.1810.901.73151.300.3740.732.32
5135Sales Clerks and Salespersons, Commodities, NEC890.860.1960.681.08170.640.0990.381.09
517Sales, Services721.390.0211.051.84241.290.2730.822.04
5171Insurance Sales311.810.0061.192.7692.220.0431.024.81
5172Real Estate Sales261.130.5740.741.7391.650.1900.783.49
519Other Sales260.880.5480.581.3481.190.6690.542.64
5193Route Drivers201.020.9360.631.6561.210.6840.483.03
61Services3650.960.5810.831.11790.950.6880.741.22
611Protective Services2600.980.8150.831.16350.890.5420.611.29
6111Firefighters90.950.8890.402.2571.140.7560.502.60
6112Police Officers and Detectives, Government161.030.9130.611.7560.790.5960.331.89
6116Commissioned Officers, Armed Forces440.880.4650.631.2480.940.8760.432.04
6117Other Ranks, Armed Forces1951.060.5300.881.2770.760.4990.3491.68
612Food and Beverage Preparation and Related550.910.5320.681.22110.670.2020.361.24
6121Chefs and Cooks241.060.7970.681.6550.700.4540.281.78
613Lodging and Other Accommodation Services280.820.3460.541.2482.000.0990.894.56
6130Supervisors230.810.3710.511.2981.900.1280.834.34
619Other Service631.120.4400.841.49181.090.7490.641.85
6190Supervisors132.010.0371.043.8752.050.1800.725.85
6191Janitors, Charworkers and Cleaners461.090.6030.791.51110.810.5240.421.55
71Farming, Horticultural and Animal Husbandry3080.920.2820.791.07951.060.6470.831.36
711Farmers1821.000.9190.831.22791.130.3530.871.46
7113Livestock Farmers461.220.2470.871.71191.300.3230.772.19
7115Crop Farmers461.090.6190.781.53160.960.8860.551.68
718/719Other Farming, Horticulture and Animal Husbandry630.840.2340.631.1261.020.9650.432.44
7183Livestock Farm Workers311.000.9610.681.5152.580.0770.907.36
7195Nursery and Related Workers211.190.4850.731.9461.470.4200.583.75
7199Other Farming, Horticulture and Animal Husbandry, NEC800.860.2280.671.1070.880.7540.401.96
73Fishing, Trapping and Related471.200.2780.861.67130.930.8140.511.70
7313Net, Trap and Line Fishing441.250.1980.891.76120.910.7660.491.70
75Forestry and Logging1211.010.9240.821.24311.300.1980.871.94
7510Foremen/women211.090.7240.681.7661.140.7780.462.84
7513Timber Cutting and Related641.070.6460.801.43131.390.2940.752.57
77Mining and Quarrying710.880.3270.681.14161.360.2940.772.42
7717Mineral Cutting, Handling and Loading340.790.2350.541.1781.400.4050.633.09
81/82Materials Processing540.780.0960.581.05741.020.8810.791.32
813/814Metal Processing and Related180.820.4350.501.3550.960.9330.372.50
821/822Food, Beverage and Related Processing471.310.1130.941.83121.030.9260.551.92
8215Slaughtering, Meat Cutting, Canning, Curing, Packing251.290.2590.832.01111.550.2210.773.13
823Wood Processing (Non-Pulp and Paper Production)1321.130.2470.921.39411.280.1730.901.83
8231Sawmill Sawyers and Related431.190.3060.851.66161.770.0530.993.15
8238Labouring511.110.5200.811.5370.930.8610.412.10
8239Wood Processing, Non-Pulp and Paper, NEC401.230.2410.871.7481.500.3270.673.37
825Pulp and Paper Production and Related210.850.5040.531.3750.740.5240.291.87
83Machining and Related1171.050.6500.851.30310.730.1060.501.07
831Metal Machining511.270.1450.921.75151.090.7710.611.95
8313Machinist and Machine Tool Setting-up371.140.4970.781.6660.580.2190.241.38
833Metal Shaping and Forming, Except Machining621.080.5970.811.44150.710.2170.411.22
8335Welding and Flame Cutting360.990.9570.691.4270.490.0810.221.09
85Product Fabricating, Assembling and Repairing2741.050.5080.911.211141.080.4870.871.34
853Electrical, Electronic Equipment561.360.5061.001.85130.690.2190.381.25
8533Electrical Equipment Installing, Repairing, NEC331.380.1110.932.0580.800.5540.381.68
854Fabricating, Assembling and Repairing: Wood Products231.300.2690.822.0792.290.0451.025.15
8541Cabinet and Wood Furniture Makers151.480.1950.822.6862.510.0630.956.64
858Mechanics and Repairers, NEC1591.100.3190.911.33691.110.4370.851.44
8581Motor Vehicle Mechanics and Repairers631.080.5970.811.44200.870.5720.541.41
8582Aircraft Mechanics and Repairers241.350.2110.842.1651.150.7830.433.10
8583Rail Transport Equipment Mechanics and Repairers113.84<0.0011.828.1166.060.0012.0418.00
8584Other Industrial Equipment Repairers640.960.7740.731.27281.030.8880.681.55
8589Other Mechanics and Repairers, NEC130.980.9480.541.7962.020.1470.785.22
859Other Product Fabrication, Assembling, Repairing490.930.6580.671.28111.170.6430.602.27
8592Marine Craft Fabricating, Assembling, Repairing361.010.9580.701.4691.650.1980.773.54
87Construction Trades2730.900.1840.771.051100.850.1370.691.05
871Excavating, Grading, Paving630.940.6710.711.25150.660.1300.391.13
8711Excavating, Grading and Related311.020.9220.691.5290.800.5390.391.63
873Electrical, Wire Communications Installing/Repair421.030.8670.731.46181.000.9990.601.71
8733Electricians and Repairers241.070.7710.681.69121.370.3360.722.60
878/879Other Construction Trade1120.840.1160.681.04500.850.3190.621.17
8780Foremen/women200.920.7280.581.4760.960.9270.402.31
8781Carpenters and Related700.860.2600.661.12270.800.3030.521.22
8782Brick and Stone Masons, Tile Setters91.290.4930.622.6772.970.0181.207.34
8791Pipefitting, Plumbing and Related270.990.9640.641.52171.200.4990.712.04
8798Labouring440.940.7170.671.3150.750.5500.291.93
8799Other Construction Trade, NEC100.800.5070.411.5551.790.2560.664.89
91Transport Equipment Operating2461.150.0770.991.34861.150.2790.891.48
911Air Transport241.510.0840.952.41101.390.3590.692.81
9111Air Pilots, Navigators and Flight Engineers161.290.3680.742.2571.240.6180.532.89
913Railway Transport231.140.5700.731.79121.290.4400.682.46
9131Locomotive Operating80.710.3870.331.5461.400.4800.553.56
9133Conductors and Brake Workers, Railway131.790.0730.953.3862.050.1460.785.40
915Water Transport511.170.3250.861.60161.170.5730.682.02
9151Deck Officers130.880.6780.481.6160.940.8900.392.26
9153Engineering Officers, Ship101.560.2190.773.1774.800.0021.8112.71
917Motor Transport, Other Transport Equipment1571.100.3190.911.33461.010.9520.731.40
9171Bus Drivers200.840.4790.521.3670.800.5930.361.77
9173Taxi Drivers and Chauffeurs301.540.0451.012.2562.250.0880.895.71
9175Truck Drivers1241.080.4600.881.33320.930.7160.631.38
93Material Handling and Related, NEC1011.040.7340.831.30260.990.9630.641.52
9313Longshore Workers, Stevedores and Freight Handlers481.130.4620.821.57161.330.3200.762.33
9315Material Handling Equipment Operators, NEC210.930.7590.591.4850.940.8960.372.39
95Other Crafts and Equipment Operating681.110.4600.841.46291.020.9250.671.55
953Stationary Engine, Utilities Equipment Operating371.160.4320.80
5		1.68161.220.4770.712.11
9539Stationary Engine, Utility Equipment, NEC251.030.8920.671.58121.180.6120.622.24
955Electronic Communications Equipment, NEC191.460.1580.862.4791.750.1590.803.82
Table
Table 5. Odds Ratios for ever and usual industries.
Table 5. Odds Ratios for ever and usual industries.
CodeIndustry TitleEverUsual
CaseORP value95% CICaseORP value95% CI
01Agriculture2960.900.1840.771.05871.000.9990.781.31
011Livestock Farms (except Animal Specialities)721.130.3770.861.48221.530.0850.942.48
0111Dairy Farms491.390.0461.011.9281.130.7570.522.45
0112Cattle Farms130.880.6780.481.6161.330.5560.523.43
0114Poultry and Egg Farms171.560.1160.902.7263.520.0161.269.81
013Field Crop Farms490.960.8060.691.3390.980.9580.462.09
0131Wheat Farms340.950.7920.651.3960.920.8610.362.34
015Fruit and Other Vegetable Farms351.040.8370.721.5190.950.8890.461.95
0151Fruit Farms321.040.8440.711.5491.070.8560.522.22
017Livestock, Field Crop, Horticultural Combination Farms1790.870.1570.721.06450.930.6740.661.31
03Fishing and Trapping491.080.6310.791.48140.900.7250.501.62
031Fishing461.150.4100.831.60130.910.7580.501.66
0311Salt Water Fishing421.140.4630.801.61120.870.6560.471.61
04Logging1350.990.9200.811.20381.130.5150.781.63
06Mining950.870.2600.681.11210.890.6270.561.42
061Metal Mines710.830.1810.631.09170.900.6930.531.52
0614Silver-Lead-Zinc Mines231.100.6820.701.7450.950.9200.352.59
0631Bituminous Coal Mines281.080.7190.711.6451.250.6620.463.40
10Food861.080.5370.851.38220.960.8630.601.53
101Meat and Poultry Products180.920.7480.551.5350.730.5140.281.88
1011Meat and Meat Products (Except Poultry)181.010.9700.601.7150.770.5990.292.04
104Dairy Products211.340.2390.822.1882.020.0910.904.56
1041Fluid Milk131.450.2420.782.7052.080.1730.735.96
11Beverage131.240.4820.682.2662.250.0840.905.64
113Brewery Products81.990.0900.904.4153.710.0151.2910.66
25Wood1891.070.4610.891.28671.100.5040.831.46
251Sawmill, Planing Mill and Shingle Mill Products1531.020.8380.841.23561.150.3700.851.56
2512Sawmill, Planing Mill (Except Shingles and Shakes)1471.030.7730.841.26541.180.2950.871.61
252Veneer and Plywood221.250.3560.782.0191.180.6560.572.45
2522Softwood Veneer and Plywood201.430.1610.872.3691.550.2480.743.26
26Furniture and Fixtures161.140.6390.661.9761.520.3660.613.77
261Household Furniture141.190.5690.652.1751.460.4500.553.907
27Paper and Allied Products490.890.4510.661.21190.810.3930.501.31
271Pulp and Paper Production450.870.4070.631.21180.800.3940.481.34
2711Pulp Industry350.790.2100.551.14160.870.6170.501.50
28Printing, Publishing and Allied240.810.3480.521.2680.520.0820.251.09
281Commercial Printing100.930.8320.481.8250.890.8110.342.31
29Primary Metal480.770.1060.561.06160.780.3580.461.33
299Other Rolled, Cast, Extruded Non Ferrous Metal Products240.920.7170.591.45100.980.9540.491.95
30Fabricated Metal Products(Non Machinery, Transport)691.130.3770.861.48190.920.7480.551.53
308Machine Shops281.490.0680.972.2961.180.7150.492.87
31Machinery (except Electrical)281.630.0251.072.5081.570.2620.713.46
319Other Machinery and Equipment241.820.0121.142.9081.860.1350.834.20
3192Construction, Mining Machinery, Materials Handling71.880.1460.804.4153.660.0231.1911.22
32Transportation Equipment1150.980.8520.791.21190.930.7770.561.54
327Shipbuilding and Repairs730.950.7050.731.24121.010.9750.541.88
33Electrical and Electronic Products211.230.4010.761.9960.950.9070.402.25
36Refined Petroleum and Coal Products161.290.3680.742.2471.610.2880.673.88
361Refined Petroleum Products131.170.6150.632.1671.610.2970.663.94
3611Refined Petroleum Products(Non Lubricating Oil, Grease)131.170.6150.632.1671.610.2970.663.94
37Chemical and Chemical Products311.420.0910.952.13101.150.6950.572.31
40Building, Developing and General Contracting1300.930.4970.751.15420.940.7170.671.31
401Residential Building and Development290.930.7280.621.4081.000.9990.462.23
4011Single Family Housing261.000.9640.651.5681.250.5830.562.78
41Industrial and Heavy Construction530.780.0960.581.05150.720.2280.421.23
412Highway and Heavy Construction440.820.2430.591.14130.780.4000.441.39
4121Highways, Streets and Bridges290.930.7280.621.4090.990.9780.482.39
42Trade Contracting1090.900.3420.721.12480.900.5140.661.23
422Structural and Related Work200.900.6690.561.4660.730.4810.301.75
423Exterior Close-In Work141.180.5820.662.1381.790.1500.813.96
4231Exterior Close-In: Masonry Work51.100.8460.422.8853.020.0451.038.89
424Plumbing, Heating, Air Conditioning Mechanical231.180.4840.741.88121.070.8340.572.01
4241Plumbing130.900.7340.491.6560.750.5190.311.80
426Electrical Work231.260.3340.792.01101.480.2850.723.04
427Interior and Finishing Work210.690.1120.441.0960.440.0510.191.01
45Transportation2821.210.0111.051.401061.080.5130.861.36
451Air Transport241.260.3200.801.99121.070.8340.572.01
4511Scheduled Air Transport160.960.8820.561.65101.030.9330.522.04
453Rail Transport and Related Service781.100.4590.861.42351.170.4190.801.71
4531Railway Transport771.100.4590.861.42341.160.4490.791.70
454Water Transport541.360.0511.001.8590.700.3160.351.41
4541Freight and Passenger Water Transport421.520.0201.072.1650.680.4190.271.73
455Services Incidental to Water Transport251.460.1090.922.32111.330.4130.672.63
4551Marine Cargo Handling151.240.4580.702.19101.540.2320.763.13
456Truck Transport721.020.8810.791.32220.930.7590.591.48
4561General Freight Trucking501.010.9500.741.37110.590.0960.321.10
4562Used Goods Moving and Storage71.920.1330.824.5057.140.0022.1124.13
457Public Passenger Transit Systems260.910.6590.601.3880.830.6290.391.77
4571Urban Transit Systems160.820.4740.481.4150.780.6100.302.03
458Other Transportation281.580.0381.032.4351.900.2090.705.17
4581Taxicab261.520.0700.972.3951.900.2090.705.17
48Communications541.060.7090.781.44250.910.6730.591.41
481Telecommunication Broadcasting91.300.4860.622.7251.550.3980.564.29
4821Telecommunication Carriers261.330.2030.862.06131.160.6290.642.12
484Postal and Courier Services200.790.3540.481.3070.530.1220.241.18
4841Postal Service180.740.2530.441.2470.530.1220.241.18
49Other Utility340.950.7820.661.37181.110.6920.661.86
4911Electric Power Systems190.830.4560.511.36100.910.7890.461.61
51Petroleum Products, WH150.870.6310.491.5460.740.4920.311.75
521Food, Beverage, Drug and Tobacco, WH291.290.2300.851.9670.690.3690.311.55
55Motor Vehicle, Parts and Accessories, WH151.400.2560.782.5072.920.0191.207.13
56Metal, Hardware, Plumbing, Heating, Building Material, WH401.260.2110.881.81120.990.9750.521.87
563Lumber and Building Materials, WH251.240.3340.801.92111.440.2970.732.86
5631Lumber, Plywood and Millwork, WH151.370.2780.782.4251.230.6790.463.28
57Machinery, Equipment and Supplies, WH451.230.2230.881.72191.240.4060.752.06
579Other Machinery, Equipment and Supplies, WH120.990.9750.531.8351.260.6390.483.31
59Other Products, WH250.870.5190.571.3360.680.3800.291.61
60Food, Beverage and Drugs, Retail550.850.2910.631.15231.010.9660.641.59
601Food Stores480.920.5970.681.25191.150.5910.691.91
6011Groceries Food Stores290.790.2600.521.1980.680.3190.321.45
6012Specialty Food Stores231.290.2880.812.06102.580.0231.145.84
62Household Furniture, Appliances, Furnishing, Retail220.980.9330.611.5750.590.2670.231.50
63Auto Vehicle, Parts, Accessories, Sale and Service860.950.6880.741.22280.810.3240.531.23
631Automobile Dealers231.170.4970.741.84111.400.3330.712.77
6311Automobile (New) Dealers231.250.3410.791.98111.520.2270.773.00
635Motor Vehicle Repair Shops480.960.8060.691.33130.720.2730.401.30
6351Motor Vehicle Repair Garages (General Repairs)420.970.8600.691.3680.500.0640.241.04
64General Retail Merchandising430.830.2660.601.15160.900.7040.521.55
641General Merchandise Stores430.830.2660.601.15160.900.7040.521.55
6411Department Stores360.910.6120.631.31141.020.9480.561.85
65Other Retail Stores360.930.7030.641.3590.640.2020.321.27
70Deposit Accepting Intermediaries190.720.1830.441.17110.980.9530.501.91
702Chartered Banks, Other Banking-Type Intermediaries140.640.1180.371.1280.920.8280.431.95
7021Chartered Banks130.660.1720.361.2070.870.7370.391.96
73Insurance Underwriters271.630.0321.042.5591.120.7590.542.31
733Property and Casualty Insurers141.460.2190.802.6771.510.3420.653.53
7339Other Property and Casualty Insurers131.380.3090.742.5761.250.6330.503.12
76Insurance and Real Estate Agencies541.260.1460.921.72261.670.0241.072.60
77Business Services791.090.5080.851.41301.030.8880.681.55
773Accounting and Bookkeeping Services100.820.5720.411.6350.980.9680.372.62
775Architectural, Engineering and Other Services371.170.4020.811.69140.970.9200.541.75
7752Offices of Engineers201.200.4730.731.9860.750.5190.311.80
7759Other Scientific and Technical Services161.140.6390.661.9761.210.6840.483.03
81Federal Government Services3481.120.1310.971.30861.240.0990.971.58
811Defence Services3161.110.1680.961.29661.410.0181.061.88
815General Administrative Service171.000.9710.591.7460.700.4170.301.66
817Economic Service Administration90.580.1320.291.1860.830.6750.351.98
82Provincial and Territorial Government Services451.110.5380.801.55201.240.4060.752.06
822Protective Services151.090.7640.621.9161.120.8030.462.73
826Human Resource Administration102.340.0241.114.8974.720.0021.7912.46
83Local Government Services330.840.3450.591.20180.960.8780.571.62
8323Police Services81.170.6920.542.5461.850.1930.734.67
8324Firefighting Services91.500.2890.712.1771.830.1680.784.32
85Educational Services881.050.7040.821.35481.010.9520.731.40
851Elementary and Secondary Education631.080.5970.811.44331.020.9190.701.50
853University Education211.170.5240.721.90111.070.8430.552.09
86Health and Social Services550.980.8960.721.33280.980.9250.651.49
861Hospitals240.750.1960.491.1690.640.2240.311.31
8611General Hospitals180.680.1240.421.1160.470.0820.201.10
865Offices: Physicians, Surgeons and Dentists, Private151.310.3680.732.36131.270.4550.682.38
8651Offices: Physicians, General Practice71.480.3710.633.4961.570.3410.623.98
91Accommodation Services480.910.5540.671.24151.390.2590.782.46
911Hotels, Motels and Tourist Courts460.950.7490.691.30131.260.4640.682.34
9111Hotels and Motor Hotels350.880.4880.611.2691.090.8120.542.22
96Amusement and Recreational Services270.970.8880.641.4860.970.9460.402.36
97Personal and Household Services190.850.5220.521.4090.930.8430.461.90
98Membership Organizations391.570.0171.082.28161.780.0580.983.23
981Religious Organizations151.170.5950.662.0981.200.6580.542.69
99Other Services270.650.0400.430.9880.690.3270.331.45

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MDPI and ACS Style

Fang, R.; Le, N.; Band, P. Identification of Occupational Cancer Risks in British Columbia, Canada: A Population-Based Case—Control Study of 1,155 Cases of Colon Cancer. Int. J. Environ. Res. Public Health 2011, 8, 3821-3843. https://0-doi-org.brum.beds.ac.uk/10.3390/ijerph8103821

AMA Style

Fang R, Le N, Band P. Identification of Occupational Cancer Risks in British Columbia, Canada: A Population-Based Case—Control Study of 1,155 Cases of Colon Cancer. International Journal of Environmental Research and Public Health. 2011; 8(10):3821-3843. https://0-doi-org.brum.beds.ac.uk/10.3390/ijerph8103821

Chicago/Turabian Style

Fang, Raymond, Nhu Le, and Pierre Band. 2011. "Identification of Occupational Cancer Risks in British Columbia, Canada: A Population-Based Case—Control Study of 1,155 Cases of Colon Cancer" International Journal of Environmental Research and Public Health 8, no. 10: 3821-3843. https://0-doi-org.brum.beds.ac.uk/10.3390/ijerph8103821

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