Table 1.
Sample, exposure and outcome characteristics
| Overall N=303 | Low As-Low Mn n=77 | Low As-High Mn n=74 | High As-Low Mn n=73 | High As-High Mn n=79 | |
|---|---|---|---|---|---|
| Mean (sd) | Mean (sd) | Mean (sd) | Mean (sd) | Mean (sd) | |
| Child age (years) | 9.64 (0.77) | 9.52 (0.80) | 9.67 (0.73) | 9.80 (0.75) | 9.56 (0.80) |
| Male [% (n)] | 49.83 (151) | 61.04 (47) | 48.65 (36) | 43.84 (32) | 45.57 (36) |
| Months attending school | 42.03 (16.27) | 43.36 (18.52) | 42.40 (14.87) | 42.58 (14.05) | 39.87 (17.18) |
| BMI | 14.06 (1.32) | 13.94 (1.03) | 14.16 (1.42) | 13.96 (1.17) | 14.17 (1.59) |
| Head circumference (cm) | 49.37 (1.42) | 49.32 (1.27) | 49.38 (1.45) | 49.08 (1.32) | 49.71 (1.75) |
| Mother's age (years) | 35.30 (6.02) | 34.55 (5.48) | 35.95 (5.96) | 35.08 (6.32) | 35.63 (6.30) |
| Mother's education (years) | 3.74 (3.69) | 4.17 (3.69) | 3.05 (3.44) | 4.33 (3.69) | 3.39 (3.80) |
| Mother's WASI Raw Score | 31.00 (10.60) | 32.05 (9.73) | 30.27 (10.66) | 31.51 (10.83) | 30.20 (11.20) |
| Home stimulation | 3.48 (1.67) | 3.75 (1.77) | 3.39 (1.72) | 3.16 (1.57) | 3.61 (1.56) |
| Water As (μg/L) | 43.32 (73.65) | 2.39 (2.32) | 3.33 (2.71) | 97.33 (108.89) | 70.74 (58.16) |
| Water Mn (μg/L) | 725.54 (730.04) | 202.14 (145.49) | 1111.19 (686.16) | 184.06 (146.19) | 1367.13(692.61) |
| Urine As (μg/L) | 78.09 (72.16) | 46.70 (35.81) | 52.30 (38.78) | 106.01 (93.01) | 107.05 (79.61) |
| Urine Creatinine (mg/dL) | 35.00 (24.16) | 35.01 (25.06) | 33.79 (24.40) | 36.81 (24.95) | 34.46 (22.61) |
| Urine As (mg/g creatinine) | 246.54 (183.93) | 149.59 (74.40) | 173.37 (111.75) | 330.51 (247.41) | 332.0 (170.42) |
| Blood As (μg/L) | 4.81 (3.22) | 3.20 (1.73) | 3.42 (1.75) | 6.27 (4.21) | 6.34 (3.04) |
| Blood Mn (μg/L) | 14.78 (3.72) | 14.58 (3.86) | 15.49 (4.15) | 14.38 (3.52) | 14.69 (3.28) |
| Blood Pb (μg/L) | 114.56 (37.22) | 123.93 (38.43) | 113.94 (42.49) | 100.97 (30.59) | 118.55 (33.12) |
| Blood Se (μg/L) | 104.97 (17.23) | 106.46 (16.29) | 103.64 (15.58) | 106.77 (18.06) | 103.09 (18.76) |
| Hemoglobin (g/dL) | 12.46 (0.99) | 12.79 (1.15) | 12.22 (0.83) | 12.33 (1.01) | 12.47 (0.88) |
| Serum ferritin (ng/mL) | 33.43 (17.89) | 31.59 (16.88) | 32.19 (17.50) | 36.93 (18.15) | 33.15 (18.83) |
| WISC-4 Raw Scores | |||||
| Verbal Comprehension | 23.80 (8.77) | 24.56 (8.32) | 22.93 (7.91) | 23.82 (8.41) | 23.85 (10.26) |
| Perceptual Reasoning | 31.24 (11.24) | 30.21 (10.61) | 30.69 (10.16) | 32.86 (10.53) | 31.25 (13.30) |
| Working Memory | 20.25 (6.06) | 20.05 (5.79) | 20.28 (6.01) | 20.42 (6.87) | 20.24 (5.66) |
| Processing Speed | 33.21 (12.48) | 32.57 (12.12) | 33.82 (11.35) | 33.63 (13.46) | 32.87 (13.07) |
| Full Scale | 108.50 (31.32) | 107.39 (30.90) | 107.73 (27.34) | 110.74 (32.51) | 108.22 (34.45) |