Table 2

Proportional hazards model results for exposed workers including rate ratios and 95% CI by cumulative exposure levels versus an internal comparison group and evaluation of linear trends

Cause	Cumulative Exposure Categories					Continuous Model
	Rate Ratio (95% CI)*				P values Linear Trend†	Continuous Model
	0–75 ppt/month (referent)	75.1–450.0 ppt-month	450.1–2000 ppt-month	2,000.1+ppt month	P values Linear Trend†	Exposure Coefficient‡ (SE)	P values§
All deaths	1.00	1.17 (0.83 to 1.66)	1.46 (1.02 to 2.07)	1.20 (0.81 to 1.76)	0.90	0.01462 (0.02643)	0.58
All cancers	1.00	1.53 (0.82 to 2.84)	1.46 (0.75 to 2.82)	1.54 (0.78 to 3.05)	0.98	0.03912 (0.04737)	0.41
Lung cancer	1.00	1.26 (0.30 to 5.24)	0.39 (0.04 to 3.60)	3.03 (0.72 to 11.73)	0.17	0.12696 (0.11372)	0.26
Non-Hodgkin lymphoma	1.00	0.00 (0.00-∞)	2.00 (0.12 to 33.36)	1.95 (0.10 to 37.03)	1.00	0.24766 (0.27255)	0.36
Diabetes mellitus	1.00	0.63 (0.10 to 3.77)	0.00 (0.00-∞)	0.39 (0.50 to 3.06)	0.67	−0.09991 (0.14776)	0.50
Ischaemic heart disease	1.00	0.89 (0.47 to 1.67)	1.11 (0.59 to 2.08)	0.70 (0.33 to 1.47)	0.51	−0.04482 (0.04831)	0.35

*The time variable was age and both models included sex, year first employed, and year of birth. Since there were no diabetes deaths among women, the model for diabetes was restricted to men.
†Tested by constructing orthogonal polynomial contrasts and computing one-degree of freedom Wald chi-square statistics and associated p values.
‡The natural log of estimated cumulative exposure.
§P value calculated by chi-square of the maximum likelihood estimator of the coefficient.