Arsenic in Drinking Water and Lung Cancer Mortality in the United States: An Analysis Based on US Counties and 30 Years of Observation (1950–1979)

Table 2

Stratified analysis of male and female lung cancer mortality by median groundwater arsenic level (µg/L).

As Median	County Wt Males	Counties Males	Cases Males	SMR; Males	95% CI; Males	RR; Males	County Wt Females	Counties Females	Cases Females	SMR; Females	95% CI; Females	RR; Females
3.0	3.0	49	12,595	0.89	(0.84–0.94)	1.00	3.0	42	3,026	0.89	(0.81–0.96)	1.00
3.1–3.9	3.5	15	1,947	0.91	(0.82–0.99)	1.02	3.5	13	455	0.90	(0.77–1.03)	1.02
4.0–4.9	4.1	25	11,199	0.88	(0.82–0.94)	0.97	4.1	21	2,907	0.89	(0.81–0.96)	0.99
5.0–5.9	5.0	18	1,251	0.92	(0.81–1.04)	1.05	5.0	11	235	0.87	(0.73–1.02)	0.98
6.0–6.9	6.1	16	1,317	0.91	(0.79–1.02)	0.98	6.1	11	251	0.93	(0.82–1.05)	1.07
7.0–7.9	7.1	11	369	0.86	(0.70–1.01)	0.94	7.2	6	61	1.05	(0.80–1.30)	1.13
8.0–9.9	8.3	15	1,413	0.94	(0.85–1.03)	1.10	8.4	10	223	0.75	(0.58–0.92)	0.71
10.0–14.9	11.2	12	1,952	0.84	(0.73–0.94)	0.89	11.3	10	385	0.87	(0.72–1.02)	1.16
15.0–24.9	20.1	7	868	0.95	(0.78–1.12)	1.13	20.4	5	170	0.84	(0.57–1.10)	0.97
25.0–59.9	39.7	3	123	0.83	(0.53–1.13)	0.88	41.2	3	31	0.82	(0.67–0.97)	0.98
3.0	3.0	49	12,595	0.89	(0.84–0.94)	1.00	3.0	49	3,026	0.877	(0.81–0.96)	1.00
3.1–9.9	5.4	100	17,496	0.90	(0.82–0.99)	1.01	5.3	72	4,132	0.890	(0.84–0.94)	1.01
10.0–59.9	17.9	22	2,943	0.87	(0.82–0.94)	0.98	18.8	18	586	0.853	(0.76–0.95)	0.97

County Wt: county weighted, SMR: standardized mortality ratio, CI: confidence interval, RR: relative risk.