Table 2

Mortality studies carried out in a cohort of workers from the hard metal industry

Reference	Type of plant	Size of the cohort Follow up (y)	Results: lung cancer	Confounders
Hogstedt and Alexandersson, 1990³³		Hard metal industry, Sweden		n=3163 men	SMR 1.34, 95% CI 0.77 to 2.13	Tobacco smoking: no individual information
				1951–82				Increase of the SMR with exposure duration and latency time
								No increase of the SMR with intensity of exposure
Lasfargueset al, 1994³⁴		Hard metal industry, France		n=709 men	SMR 2.13, 95% CI 1.02 to 3.93 (whole cohort)	Tobacco smoking considered
				1956–89				No significant increase of the SMR with increasing duration of exposure and latency time
								Significant increase of SMR in the high exposure group
Moulin et al, 1998³²		Hard metal industry, France		n=7459 men and women (separate men and women)		SMR 1.30, 95% CI 1.00 to 1.66	Tobacco smoking considered
						Significant increase of SMR with intensity and duration of exposure

1968–91