Table 3

Distribution of cohort members (n=8933) by categories of exposure to nitrosamines and date of hire

Date of start of employment		Exposure category 1				Exposure category 2
Date of start of employment		n	%			n	%
1950–9:
High	1363	30.6		945	21.2
Medium	1176	26.4		1645	36.9
Low	1683	37.8		1629	36.6
Missing	231	5.2		234	5.3
1960–9:
High	899	28.4		586	18.5
Medium	787	24.8		1145	36.1
Low	1359	42.9		1312	41.4
Missing	123	3.9		125	3.9
1970–80:
High	189	14.4		36	2.7
Medium	274	20.9		477	36.4
Low	738	56.3		714	54.4
Missing	111	8.5		85	6.5
Overall:
High	2451	27.4		1567	17.5
Medium	2237	25.0		3267	36.6
Low	3780	42.3		3655	40.9
Missing	465	5.2		444	5.0