Table 2

Overall and zone specific rate ratio estimates for mesothelioma by years of employment in taconite

CasesControlsRR*95% CI
Taconite years571841.031.00 to 1.06
Haematite years†482120.990.94 to 1.04
High vs low employment‡
 <6.74 years26921.00
 ≥6.74 years31921.230.67 to 2.28
 Haematite only231310.590.30 to 1.14
Years employment tertiles§
 <1.65 years (REF)13611.00
 ≥1.65<12.91 years23611.900.86 to 4.20
 ≥12.91 years21621.620.73 to 3.58
 Haematite only231310.780.36 to 1.72
Employment by geological zone¶
 Zone 1 taconite years18741.051.00 to 1.11
 Zone 2 taconite years31581.061.02 to 1.09
 Zone 4 taconite years12660.970.92 to 1.03
  • *Rate ratio; adjusted for age, and years of employment in haematite.

  • †Years in haematite include those employed in haematite only and in both taconite and haematite.

  • ‡High group represents workers with employment duration greater than the control median duration.

  • §Based on lower, middle, and upper third of control employment duration distribution.

  • ¶Results adjusted for age, employment in haematite, and employment in other zones. Cases and controls may have worked in more than one zone.

  • REF, referent comparison group.