Kidney Cancer

Background
What is kidney cancer?

Kidney cancer rates have increased over time, which is attributable to changes in medical imaging for disease detection as well as changes in the prevalence of lifestyle and behavioural risk factors [1]. Tobacco smoking is the largest well-known risk factor for kidney cancer and increases the risk of disease by 50% [2].

 

Known Occupational Risk Factors
  • X- and gamma radiation [3]
  • Trichloroethylene (TCE) [3]

 

Possible Occupational Risk Factors
  • Arsenic and inorganic arsenic compounds [3]
  • Cadmium and cadmium compounds [3]
  • Perfluorooctanoic acid (PFOA) [3]
  • Printing processes [3]
  • Welding fumes [3]
  • Gasoline and diesel exhaust [4]
Key Findings

Increased risks of kidney cancer were detected among groups potentially exposed to TCE, one of the few well-established occupational risk factors for kidney cancer, including metal manufacturing, several metalworking occupations, and certain transportation equipment manufacturing industries. There was also a strong elevated risk among firefighting occupations, who may be exposed to many different chemicals [5,6]. No excess risk was observed among workers in printing-related occupations or industries or among welders and flame cutters.

 
Metal Work

Workers in metal manufacturing, including metalworkers, may be exposed to TCE, which is used for metal degreasing. These workers tend to be the most heavily exposed [7]. Metal machine tool operators are among the largest occupational groups exposed to TCE [8]. Workers in metal-related occupations may also be exposed to cadmium. Groups working with minerals containing copper and iron, which showed increases risks in the ODSS, may also be exposed to arsenic [9].

    • Moulding, coremaking, and metal casting occupations: 1.41 times the risk
    • Occupations in labouring and other elemental work, metal processing: 1.37 times the risk
    • Metal machine tool operating occupations: 1.34 times the risk
    • Primary metal manufacturing industries: 1.23 times the risk
      • Iron foundries: 1.58 times the risk
      • Copper and copper alloy rolling, casting and extruding: 1.57 times the risk
      • Iron and steel mills: 1.21 times the risk

 

Transportation Equipment Manufacturing

TCE may be used to degrease metal parts in motor vehicle manufacturing. Cadmium batteries are used in the railroad industry as a source of emergency power and for starting engines [10].

    • Aircraft fabricating and assembling occupations, not elsewhere classified: 1.39 times the risk
    • Motor vehicle manufacturers industry: 1.17 times the risk
    • Railroad rolling stock manufacturing industry: 1.56 times the risk

 

Fire-Fighting Occupations

Firefighters are exposed to potentially harmful substances and work-related circumstances including shiftwork, flame retardants, and diesel engine exhaust, and when fighting fires where they can be exposed to various mixtures of particulates, gases and fumes [11]. More recent studies [12–14] and meta-analyses [11,15–17] have generally not found consistent evidence of an increased risk of kidney cancer associated with firefighting.

    • Fire-fighting occupations: 1.55 times the risk

 

Truck Drivers

Truck drivers showed increased risks of kidney cancer, which may relate to high smoking prevalence. Emerging research has also linked occupational gasoline and diesel exhaust with increased risk of kidney cancer [4].

    • Truck drivers: 1.29 times the risk

 

Other Findings

Elevated risks of kidney cancer were also observed for several additional groups with potential exposure to TCE and PFOA. Launderers and dry cleaners, a group that may work with PFOA and TCE to remove stains, showed an increased risk of disease that was based on a relatively small number of cases. Other groups with potential exposure to TCE, including groups within textile fabricating, assembling and repair (e.g., sewing machine operators) had small or no cases of kidney cancer, or too few cases to generate precise estimates. Occupational risks for kidney cancer among baking occupations are unclear.

Certain nursing subgroups showed elevated rates of kidney cancer, but this was not consistently observed. For instance, nurses and orderlies are among the occupation groups with the largest number of workers exposed to ionizing radiation [18]. Nurses showed decreased rates of kidney cancer, but orderlies and other groups within nursing showed increased rates.

    • Bonding and cementing occupations, rubber, plastic and related products: 1.84 times the risk
    • Nursing, therapy and related assisting occupations, nec*: 1.51 times the risk
    • Materials handling equipment operators nec: 1.42 times the risk
    • Launderers and dry cleaners: 1.41 times the risk
    • Bakers and confectionery makers: 1.37 times the risk
    • Stationary engine and utilities equipment operating and related occupations nec: 1.35 times the risk
    • Textile processing occupations: 1.30 times the risk
    • Nursing aides and orderlies: 1.21 times the risk

 

*Nursing therapy and related assisting occupations, nec, include workers who provide support in diagnostic and therapeutic procedures

Relative Risk by Industry and Occupation

Figure 1. Risk of kidney cancer diagnosis among workers employed in each industry group relative to all others, Occupational Disease Surveillance System (ODSS), 1999-2016

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 kidney cancer diagnosis among workers employed in each occupation group relative to all others, Occupational Disease Surveillance System (ODSS), 1999-2016 

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 Kidney Cancer: 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 81 35011 0.85 (0.68-1.06)
2/3 Forestry, Fishing and
Trapping
42 10698 0.94 (0.69-1.27)
4 Mines, Quarries and
Oil Wells
110 23207 0.97 (0.80-1.17)
5 Manufacturing 2608 693516 1.01 (0.97-1.07)
6 Construction 748 210968 1.01 (0.93-1.09)
7 Transportation, Communication
and Other Utilities
776 197177 1.11 (1.03-1.20)**
8 Trade 1194 429242 1.01 (0.95-1.08)
9 Finance, Insurance and
Real Estate
103 23986 1.20 (0.99-1.46)
10 Community, Business and
Personal Service
1501 599525 1.00 (0.94-1.06)
11 Public Administration and
Defense
758 190853 1.14 (1.06-1.23)***
         
         
* SIC: Standard Industrial Classification (1970)    
† Hazard rate in each group relative to all others    

 

Table 2. Surveillance of Kidney Cancer: 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
88 30986 1.00 (0.81-1.24)
21 Natural sciences, engineering
and mathematics
80 26338 0.92 (0.74-1.15)
23 Social sciences and
related fields
60 30710 1.06 (0.82-1.37)
25 Religion   128
27 Teaching and related 95 48478 0.78 (0.64-0.96)*
31 Medicine and health 329 135333 1.10 (0.98-1.23)
33 Artistic, literary,
recreational and related
30 14994 0.94 (0.66-1.35)
41 Clerical and related 570 197314 1.04 (0.95-1.13)
51 Sales 314 148106 0.95 (0.85-1.07)
61 Service 1072 370832 1.03 (0.96-1.10)
71 Farming, horticultural
and animal husbandry
113 50140 0.83 (0.69-1.00)
73 Fishing, hunting,
trapping and related
<5 557
75 Forestry and logging 37 10683 0.87 (0.63-1.20)
77 Mining and quarrying,
including oil and gas field
64 13043 1.03 (0.81-1.32)
81 Processing
(mineral, metal, chemical)
271 79234 1.01 (0.90-1.14)
82 Processing
(food, wood, textile)
355 99234 1.15 (1.04-1.28)**
83 Machining and related 735 189407 1.01 (0.93-1.09)
85 Product fabricating,
assembling and repairing 
1223 328276 0.99 (0.93-1.06)
87 Construction trades 849 215587 1.02 (0.94-1.09)
91 Transport equipment
operating
775 168070 1.25 (1.16-1.35)***
93 Materials handling and related,
not elsewhere classified
522 153047 1.06 (0.97-1.16)
95 Other crafts and
equipment operating
113 28301 1.04 (0.86-1.25)
99 Other occupations not elsewhere classified 696 215234 1.01 (0.93-1.09)
         
         
* 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

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