Table 1.

Characteristics of the group, Cu concentration in test waters, Cu intake in waters, and test water consumption.

	Groups by Cu concentration in water (mg/L)
	0 (n = 343)	2 (n = 327)	4 (n = 355)	6 (n = 340)
Age (years; mean ± SD)	37.4 ± 14.5	36.9 ± 13.8	37.0 ± 15.0	38.5 ± 15.3
Female [n (%)]	184 (53.6)	161 (49.2)	166 (46.8)	162 (47.6)
Out of home (%)a	73.8	70.3	71.0	71.5
Schooling < 8 years (%)b	46.7	45.0	46.5	45.6
[Cu] (mg/L; mean ± SD)c	0.05 ± 0.16	2.02 ± 0.25	3.71 ± 0.8	5.77 ± 1.0
Cu intake (mg/day; mean ± SD)d	0.08 ± 0.31	3.6 ± 1.4	6.9 ± 2.8	11.0 ± 4.4
Fluid intake [L/day; median (25th percentile–75th percentile)]e
Total	1.7 (1.3–2.3)	1.7 (1.4–2.2)	1.7 (1.3–2.2)	1.8 (1.4–2.3)
Mixed water	1.3 (1.0–1.7)	1.4 (1.1–1.7)	1.3 (1.0–1.7)	1.4 (1.1–1.8)
Plain water	0.4 (0.1–0.7)	0.4 (0.1–0.6)	0.35 (0.1–0.6)	0.41 (0.2–0.7)

There were no statistically significant differences in the general characteristic among groups.

^aPercentage of subjects ≤ 8 hr out of home, obtained from the median of hours absent from home per individual per weekdays.

^bPercentage of subjects with < 8 years of schooling (eight years of education represents a complete basic school education in the Chilean educational system).

^cCu concentration in water prepared at home.

^dCu intake from water prepared at home.

^eFluid intake was calculated from average daily fluid consumption for each start–stop period (counting-process analysis).