Table 2.

Unadjusted and multivariable adjusted associations between residential drinking water arsenic exposure and anemia.

Average arsenic concentration (μg/L)	Anemia	Unadjusted estimates		Multivariable model 1 a, b		Multivariable model 2 c
	(Yes/No)	PPR	95% CI	PPR	95% CI	PPR	95% CI
Any anemia
0 μg/L	8/92	1.00	Referent	1.00	Referent	1.00	Referent
>0 μg/L	17/100	1.82	0.82-4.03	1.71	0.75-3.88	1.62	0.70-3.76
>0-5 μg/L	13/72	1.91	0.83-4.39	1.81	0.77-4.26	1.71	0.71-4.15
>5 μg/L	4/28	1.56	0.50-4.85	1.41	0.44-4.47	1.39	0.46-4.22
P for trend	-	0.214	-	0.328	-	0.368	-
Pregnancy anemia
0 μg/L	2/92	1.00	Referent	1.00	Referent	1.00	Referent
>0 μg/L	8/100	3.48	0.76-15.99	2.87	0.62-13.26	2.44	0.50-11.87
>0-5 μg/L	7/72	4.16	0.89-19.48	3.44	0.74-16.08	2.86	0.57-14.42
>5 μg/L	1/28	1.62	0.15-17.23	1.25	0.12-12.94	1.26	0.13-12.04
P for trend	-	0.174	-	0.402	-	0.478	-
Non-pregnancy anemia
0 μg/L	6/92	1.00	Referent	1.00	Referent	1.00	Referent
>0 μg/L	9/100	1.35	0.50-3.65	1.31	0.47-3.65	1.34	0.48-3.75
>0-5 μg/L	6/72	1.26	0.42-3.74	1.26	0.41-3.84	1.29	0.42-3.97
>5 μg/L	3/28	1.58	0.42-5.95	1.44	0.38-5.50	1.45	0.38-5.43
P for trend	-	0.489	-	0.568	-	0.550	-

^aAdjusted for education (less than high school, high school, university degree) and cigarette smoking (never, ever).

^bAdditional adjustment for continuous maternal pre-pregnancy body mass index did not meaningfully impact the effect estimates.

^cAdjusted for education (less than high school, high school, university degree), cigarette smoking (never, ever), and self-reported history of physician diagnosed kidney disease (no, yes).

CI, confidence interval; PPR, prevalence proportion ratio.