Table 2.

Drinking water nitrate from public water supplies and measured and modeled private wells and the risk of bladder cancer among New England Bladder Cancer Study participants with a nitrate estimate for >=70% of exposure-years from 1970 to diagnosis/reference date (987 cases and 1180 controls)^a

Average nitrate concentration (mg/L NO₃-N)^b	Cases	Controls	OR (95% CI)^c	p-trend^d

≤0.21 mg/L	259	293	1.0 Ref.
>0.21-0.37 mg/L	212	294	0.81 (0.61-1.1)
>0.37-0.68 mg/L	229	294	0.89 (0.68-1.2)
>0.68-2.07 mg/L	221	241	1.0 (0.79-1.4)
>2.07 mg/L	66	58	1.5 (0.97-2.3)
p-trend^d				0.01

Average daily nitrate intake (mg NO₃-N)^b	Cases	Controls	OR (95% CI)^c

≤0.30 mg	214	295	1.0 Ref.
>0.30-0.62 mg	227	295	1.1 (0.87-1.5)
>0.62-1.29 mg	244	295	1.1 (0.86-1.5)
>1.29-4.59 mg	243	236	1.5 (1.1-1.9)
>4.59 mg	59	59	1.4 (0.89-2.2)
				0.06

Both residential and workplace measures were included where available, as well as measured and modeled private well values; participants with missing water intake were excluded

Exposure categories represent quartiles, with the top category reflecting an additional cut at 95th percentile

Adjusted for age, gender, smoking status, high-risk occupation, race, ethnicity, state, and average TTHM concentration for all models, as well as total water intake (L/d) for average nitrate concentration model

Based on median values for quantiles of drinking water nitrate entered into the model as a continuous variable; median for top 95th percentile average nitrate was 3.64 mg/L

CI indicates confidence interval, OR odds ratio.