Table 2.

HRs^* for respiratory symptoms by levels of baseline water and urinary arsenic concentrations^†

	Chronic cough HR (95% CI) n=859	Breathing problem HR (95% CI) n=1169	Blood in sputum HR (95% CI) n=238
Water arsenic (μg/l)
≤7	1.0	1.0	1.0
7–40	1.19 (0.95 to 1.50)	1.44 (1.20 to 1.74)	1.15 (0.75 to 1.76)
40–90	1.40 (1.11 to 1.75)	1.52 (1.25 to 1.84)	1.09 (1.69 to 1.70)
90–178	1.57 (1.25 to 1.97)	1.42 (1.16 to 1.73)	1.66 (1.10 to 2.51)
>178	1.60 (1.27 to 2.01)	1.41 (1.56 to 1.72)	1.51 (0.98 to 2.32)
Urinary arsenic (μg/g creatinine)
≤90	1.0	1.0	1.0
90–160	0.98 (0.78 to 1.23)	1.14 (0.95 to 1.38)	1.16 (0.77 to 1.74)
160–246	1.14 (0.91 to 1.42)	1.16 (0.96 to 1.40)	1.05 (0.69 to 1.60)
246–406	1.52 (1.23 to 1.88)	1.28 (1.06 to 1.54)	1.03 (0.67 to 1.58)
>406	1.51 (1.21 to 1.87)	1.27 (1.05 to 1.53)	1.33 (0.89 to 1.99)

Adjusted for age, gender, body mass index, smoking, education, skin lesion and well switching status.

^*Estimated from Cox proportional hazard models.

^†Cut-off points were determined on the quintiles of the overall study population.