Table 4.

Prevalence ratios of hypertension by quartiles of inorganic and methylated arsenic exposure, stratified by study center.

	Model 1		Model 2		Model 4		Model 5
	PR	95% CI	PR	95% CI	PR	95% CI	PR	95% CI
Arizona
1	1.00	Referent	1.00	Referent	1.00	Referent	1.00	Referent
2	4.12	1.54, 10.97	3.66	1.39, 9.64	2.78	1.18, 6.57	3.36	1.29, 8.73
3	4.52	1.53, 13.40	3.96	1.54, 10.19	2.47	1.16, 5.29	3.81	1.50, 9.66
4	4.48	1.34, 14.95	3.71	1.41, 9.77	2.18	1.05, 4.53	3.39	1.29, 8.89
Oklahoma
1	1.00	Referent	1.00	Referent	1.00	Referent	1.00	Referent
2	1.00	0.75, 1.33	0.83	0.61, 1.12	0.87	0.68, 1.11	0.84	0.62, 1.14
3	1.02	0.73, 1.44	0.87	0.59, 1.28	0.94	0.70, 1.26	0.89	0.59, 1.33
4	1.06	0.74, 1.53	0.85	0.59, 1.23	0.95	0.69, 1.29	0.88	0.60, 1.29
North and South Dakota
1	1.00	Referent	1.00	Referent	1.00	Referent	1.00	Referent
2	0.66	0.43, 1.02	0.72	0.45, 1.15	0.73	0.47, 1.12	0.71	0.44, 1.14
3	0.69	0.46, 1.06	0.70	0.47, 1.05	0.77	0.53, 1.10	0.70	0.47, 1.04
4	1.16	0.71, 1.91	1.54	0.87, 2.72	1.70	1.09, 2.66	1.52	0.87, 2.64

Models are generalized estimating equation Poisson models for prevalent hypertension defined as (defined as SBP≥140 mm Hg, DBP≥90 mm Hg, or taking hypertension medication), with exchangeable covariance conditional on family membership.

Model 1: Adjusted only for arsenobetaine and log urine creatinine

Model 2: Further adjusted for age, sex, education, drinking status, smoking status, BMI, kidney function, diabetes status, physical activity, diet index, total daily caloric intake

Model 4: Model 2, without adjustment for urine creatinine

Model 5: Model 2, without adjustment for arsenobetaine