Table 4.

Sensitivity of regression estimates of the excess relative rate (ERR) of lung cancer mortality per 100 working level months (WLMs) to restrictions based on attained age, cumulative exposure, or exposure rate. Pooled Uranium Miners Analysis (PUMA) of uranium miners in Canada, Czech Republic, France, Germany, and the United States, male miners hired in 1960 or later.

Person-time and events restricted to:	Attained age $<75$ ya		$\le 50$ WLMb		$<1$ WLc
	Estimate	(95% CI)	Estimate	(95% CI)	Estimate	(95% CI)
ERR/100 WLM	7.82	(2.95, 17.99)	7.97	(2.43, 16.25)	7.56	(2.58, 22.62)
Age at exposure (y)
$\ge 35$	1	—	1	—	1	—
$<35$	0.61	(0.31, 1.29)	0.59	(0.26, 1.40)	0.62	(0.24, 1.66)
Attained age (y)
$<55$	1	—	1	—	1	—
55–64	0.55	(0.24, 1.29)	0.83	(0.30, 2.72)	0.75	(0.24, 2.64)
65–74	0.20	(0.06, 0.54)	0.19	(0.04, 0.86)	0.12	(0.01, 0.63)
$\ge 75$	—		0.12	(0.00, 1.22)	0.43	(0.06, 2.44)
Exposure rate (WL)
$<0.5$	1	—	1	—	1	—
0.5–$<1$	1.26	(0.49, 2.88)	0.97	(0.17, 2.59)	0.79	(0.04, 2.37)
$\ge 1$	0.37	(0.15, 0.85)	0.30	($–0.17$, 1.14)	—	—
Lung cancer deaths ($n$)	1,143	—	1,000	—	962	—
Person-years ($\times {10}^5$)	18.75	—	17.93	—	17.43	—

Note: Adjusted for attained age, calendar period, study cohort, and duration of employment as a uranium miner. —, not applicable; WL, working level.

^a Restricted to person-time and events for which attained age $<75\mathrm{y}$.

^b Restricted to person-time and events for which cumulative exposure, lagged 5 y, $\le 50$ WLM.

^c Restricted to person-time and events for which annual exposure rate $<1$ WL.