Table 4

Incidence RRs of Alzheimer’s disease, ‘Alzheimer’s and other dementias’, Parkinson’s disease, and parkinsonism among workers in mining industries or occupations compared to workers in non-mining industries or occupations in subcohorts for each outcome

Alzheimer’s disease
(2006–2016)
‘Alzheimer’s and other dementias’ (1999–2016)Parkinson’s disease
(2006–2016)
Parkinsonism
(1999–2016)
CasesRR (95% CI)CasesRR (95% CI)CasesRR (95% CI)CasesRR (95% CI)
By mining industry classification (SIC code)
Workers in non-mining industries36961.00 (–)36 1861.00 (–)35721.00 (–)81301.00 (–)
Workers in industry of mines (including milling), quarries and oil wells (04)880.99 (0.80 to 1.23)8140.95 (0.89 to 1.02)871.06 (0.86 to 1.32)1740.95 (0.81 to 1.10)
Major industry groups
 Workers of metal mines (09)691.00 (0.79 to 1.27)6140.95 (0.87 to 1.03)671.08 (0.85 to 1.38)1270.93 (0.78 to 1.10)
 Workers of non-metal mines (10)* 51.27 (0.53 to 3.04)441.17 (0.87 to 1.57)61.62 (0.73 to 3.61)161.95 (1.19 to 3.18)
 Workers of quarries and sand pits (12)90.98 (0.51 to 1.89)810.83 (0.67 to 1.04)80.86 (0.43 to 1.73)160.73 (0.45 to 1.19)
 Workers of services incidental to mining (13)50.66 (0.28 to 1.60)810.98 (0.78 to 1.21)70.89 (0.42 to 1.86)150.78 (0.47 to 1.30)
Minor industry groups under metal mines
 Workers of gold mines (051 and 052)141.49 (0.88 to 2.52)1061.10 (0.91 to 1.33)91.09 (0.57 to 2.10)190.95 (0.60 to 1.49)
 Workers of uranium mines (057)<5580.97 (0.75 to 1.25)50.85 (0.35 to 2.04)120.81 (0.46 to 1.43)
 Workers of miscellaneous metal mines (059)††500.93 (0.71 to 1.24)4420.91 (0.83 to 1.00)521.10 (0.83 to 1.44)970.95 (0.78 to 1.16)
By Mining Occupation Classification (CCDO code)
Workers in non-mining occupations37271.00 (–)36 5751.00 (–)36131.00 (–)82171.00 (–)
Workers in mining and quarrying including oil and gas field occupations (77)571.28 (0.98 to 1.66)4260.95 (0.87 to 1.05)461.08 (0.81 to 1.44)880.90 (0.73 to 1.12)
Minor occupation groups
 Foremen (7710)71.18 (0.56 to 2.48)500.93 (0.70 to 1.23)<560.56 (0.25 to 1.25)
 Workers in rock and soil drilling occupations (7713)171.20 (0.74 to 1.93)1360.98 (0.83 to 1.16)211.60 (1.04 to 2.45)311.04 (0.73 to 1.48)
 Workers in cutting, handling and loading occupations (7717)221.28 (0.84 to 1.95)1660.94 (0.80 to 1.09)160.93 (0.57 to 1.53)340.86 (0.61 to 1.21)
 Workers in labouring and other elemental work (7718)81.39 (0.69 to 2.78)580.98 (0.75 to 1.26)<590.65 (0.34 to 1.25)
 Workers in other occupations (7719)101.42 (0.76 to 2.64)610.75 (0.58 to 0.96)81.00 (0.50 to 2.00)201.02 (0.66 to 1.59)
Both Mining Industry and Occupation Classification (SIC and CCDO codes)
Workers in non-mining industries36961.00 (–)36 1861.00 (–)35721.00 (–)81301.00 (–)
Workers in industry of mines and occupations of mining and quarrying (SIC 04 and CCDO 77)501.20 (0.91 to 1.59)3830.93 (0.84 to 1.03)421.08 (0.80 to 1.46)790.90 (0.72 to 1.12)
Workers in metal mines and occupations of mining and quarrying
(SIC 09 and CCDO 77)
471.26 (0.94 to 1.68)3390.94 (0.84 to 1.04)371.08 (0.78 to 1.49)670.87 (0.69 to 1.11)
Workers in non-metal mines and occupations of mining and quarrying (SIC 10 and CCDO 77)<591.10 (0.57 to 2.11)<5<5
Workers in gold mines and occupations of mining and quarrying
(SIC (051 and 052) and CCDO 77)
81.26 (0.63 to 2.52)691.05 (0.83 to 1.32)81.43 (0.72 to 2.86)171.25 (0.78 to 2.01)
Workers in uranium mines and occupations of mining and quarrying (SIC 057 and CCDO 77)<5331.02 (0.72 to 1.43)<550.59 (0.25 to 1.42)
Workers in miscellaneous metal mines and occupations of mining and quarrying (SIC 059 and CCDO 77)361.27 (0.92 to 1.77)2350.89 (0.78 to 1.01)261.01 (0.69 to 1.49)470.84 (0.63 to 1.12)
  • Follow-up was censored at age 100 years old. All models were adjusted by mean age, age2 and birth year. Results for workers in rotary well-drilling and related occupations (CCDO 7711) and blasting occupations (CCDO 7715) were not presented due to the total number of workers under 500 and small case counts (<5) for most neurodegenerative outcomes.

  • Alzheimer’s disease: at least one record with one diagnostic code (ICD-10: G30) in any diagnostic field in DAD or NACRS.

  • Alzheimer’s and other dementias: At least one record with one diagnostic code (ICD-10 F00, F01, F02, F03, G30) in any diagnostic field in DAD or NACRS or at least two physician encounters with at least one diagnostic code in OHIP (OHIP code 290, 331) within 12 months.

  • Parkinson’s disease: at least one record with one diagnostic code (ICD10: G20) in any diagnostic field in DAD or NACRS.

  • Parkinsonism: at least one record with one diagnostic code ICD-10 G20, G21.0-0.4, G21.8-9, G22, F02.3) in any diagnostic field in DAD or NACRS or at least two physician encounters with at least one diagnostic code in OHIP (OHIP code 332) within 12 months.

  • *Workers in non-metal minesinclude those ever employed in Coal Mines, Crude Petroleum and Natural GasIndustry, Asbestos Mines, Peat Extraction, Gypsum Mines and MiscellaneousNon-metal Mine which consists of 66% of saltmines.

  • †Miscellaneous metal mines consist ofnickel (78%) and zinc mines (13%), and others (9%) in the ODSS cohort.

  • CCDO, Canadian Classification Dictionary of Occupations; DAD, Hospital Discharge Abstract Database; NACRS, National Ambulatory Care Reporting System; OHIP, Ontario Health Insurance Plan Claims Database; RR, rate ratio; SIC, Standard Industrial Classification.