Table 2

Statistical interactions expressed as RIRRs representing an estimate of the ratio of the individual IRRs for the defined groups (A–J) for the stated time periods as defined in the methods

IDControl of isocyanate exposure in  MVRTime periodsType of ill-healthTime periods comparedA. All workers: spray paint vs other agentB.  MVR  vs other industries (all agents)C. Motor vehicle manufacture vs other industries (all agents)
1HSE intervention (2004–2007)time1=2001–2003
SLRDtime2/time11.210.74 to 1.970.340.12 to 0.951.380.92 to 2.07
time3/time11.030.56 to 1.871.670.78 to 3.611.050.64 to 1.70
Asthmatime2/time11.260.75 to 2.090.390.14 to to 1.92
time3/time11.290.70 to 2.401.850.80 to 4.280.930.55 to 1.58
IDCraft bakeries: exposure to flour dust and enzymes in improversTime periodsType of ill-healthTime periods comparedD. All workers: flour vs other agentsE. Food industry: flour vs other agentsF. Attributed to flour in bakers: retail vs industrial
2aIntroduction of a MEL (April 2001)
Introduction of a WEL (25 April 2005)
HSE inspection pack (2006–2008)
time1=May 1999–Apr 2001
time2=May 2001–Apr 2003
time3=May 2003–Apr 2005
time4=May 2005–2008
SLRDtime2/time11.540.89 to 2.681.600.66 to 3.868.452.36 to 30.33
time3/time12.091.22 to 3.572.050.85 to 4.923.631.17 to 11.20
time4/time12.351.42 to 3.892.301.00 to 5.312.500.88 to 7.17
time5/time13.031.69 to 5.434.691.49 to 14.745.491.65 to 18.23
Asthmatime2/time11.370.76 to 2.471.370.54 to 3.487.031.85 to 26.76
time3/time11.951.11 to 3.421.900.75 to 4.773.120.95 to 10.27
time4/time12.241.33 to 3.792.320.96 to 5.602.500.83 to 7.57
time5/time12.901.55 to 5.435.361.35 to 21.235.791.56 to 21.40
2bIntroduction of a WEL (25 April 2005)
HSE inspection pack (2006–2008)
time3=May 2003–Apr 2005
time4=May 2005–2008
SLRDtime4/time31.120.73 to 1.741.130.51 to 2.480.690.30 to 1.59
time5/time31.450.86 to 2.452.290.75 to 6.961.520.55 to 4.16
time5/time41.290.79 to to 5.992.190.87 to 5.52
Asthmatime4/time31.150.72 to 1.841.220.52 to 2.880.800.33 to 1.93
time5/time31.490.83 to 2.662.830.73 to 11.031.850.60 to 5.68
time5/time41.290.75 to 2.232.320.61 to 8.792.310.82 to 6.50
IDControlling inhalation exposure to metalworking fluidsTime periodsType of ill-healthTime periods comparedG. All workers: MWF vs other agentsH. All workers: MWF vs other agents (excluding one reporter*)
3HSE inspection pack and removal of MEL without replacement with WEL (2005–2006)time1=2002–2004
SLRDtime2/time12.201.19 to 4.062.690.87 to 8.33
time3/time12.021.05 to 3.894.611.55 to 13.72
Asthmatime2/time12.201.10 to 4.431.590.39 to 6.44
time3/time11.120.47 to 2.702.060.51 to 8.37
IDControlling inhalation exposure to rosin based solder fumeTime periodsType of ill-healthTime periods comparedI. All workers: solder vs other agents
4Introduction MEL (March 1999)
Introduction of WEL (25 April 2005)
HSE inspection pack (2007–2008)
time1=Jan 1996–Mar 1999
time2=Apr 1999–May 2002
time3=Jun 2002–Apr 2005
time4=May 2005–Dec 2008
time5=Jan 2009–Dec 2010
time3/time10.640.35 to 1.16
time4/time10.450.23 to 0.88
time5/time10.690.30 to 1.57
Asthmatime2/time10.920.55 to 1.55
time3/time10.640.34 to 1.19
time4/time10.480.25 to 0.94
time5/time10.730.30 to 1.77
IDWood dust: Controlling inhalation exposureTime periodsType of ill-healthTime periods comparedJ. All workers: wood dust vs other agents
5Introduction of WEL (25 April 2005)
HSE inspection pack (2002–2007)
SLRDtime2/time10.890.42 to 1.87
time3/time11.180.56 to 2.48
Asthmatime2/time11.040.48 to 2.26
time3/time11.310.58 to 2.97
  • The RIRR can be considered an estimate of the magnitude of the difference in the change in incidence between the groups over the defined time periods.

  • *Analysis G was repeated excluding the reporter investigating the outbreak of respiratory disease related to MWF.16 ,17

  • HSE, UK Health and Safety Executive; MEL, maximum exposure limit; MWF, metalworking fluid; RIRR, ratio of incidence rate ratios or interaction term; SLRD, short latency respiratory disease (includes asthma, allergic alveolitis, rhinitis, inhalation accidents); WEL, workplace exposure limit.