Table 9.

Analysis of additive interactions between occupational hazards on HUA in steelworkers

Variable	RERI (95% CI)	AP (95% CI)	SI (95% CI)
Shift worka × heat exposure	-0.170(-0.192–1.152)	-0.061(-0.533–0.410)	0.912(0.467–1.783)
Shift worka × dust exposure	-0.464(-2.122–1.194)	-0.170(-0.773–0.432)	0.788(0.372–1.670)
Heat exposure × dust exposure	1.464(0.677–2.251)	0.558 (0.362–0.754)	10.250(0.394–266.490)

^aDichotomous variables were used for the analysis. Ever shifts and current shifts were combined as shifts. The shift work was divided into never-shifts and shifts