Table 1
Sociodemographic and exposure characteristics of the study sample.
| SOCIODEMOGRAPHIC CHARACTERISTICS | N (%) |
|---|---|
| Child sex | |
| Female | 227 (50.4) |
| Male | 223 (49.6) |
| Age (years) | |
| 7–8 | 379 (84.2) |
| 9–10 | 71 (15.8) |
| Belonging to indigenous peoples | |
| No | 246 (54.7) |
| Aymara | 171(38.0) |
| Other | 33 (7.3) |
| Mother’s or tutor’s education | |
| 0–8 years | 30 (6.7) |
| 9–12 years | 217 (48.2) |
| ≥13 years | 203 (45.1) |
| People living in the same house | |
| 2–4 | 210 (46.7) |
| 5–14 | 240 (53.3) |
| History of grade repetition | |
| Yes | 14 (3.1) |
| Attending the School Integration Program | |
| Yes | 110 (25.3) |
| Attendance at special or differential school | |
| Yes | 133 (29.6) |
| Screen exposure (day hours) | |
| 0–2 | 121 (26.9) |
| 3–10 | 329 (73.1) |
| Household pesticide use | |
| Yes | 214 (47.6) |
| Father or mother beneficiary of the Polymetal Law | |
| Yes | 72 (16.0) |
| ASD reported by parents | |
| Yes | 24 (5.3) |
| ADHD reported by parents | |
| Yes | 41 (9.1) |
| NDD (ASD or ADHD) reported by parents | |
| Yes | 54 (12.0) |
[i] Note: ASD, autism spectrum disorder; ADHD, attention deficit hyperactivity disorder; NDD, neurodevelopmental disorders.
Table 2
Prevalence of ASD, ADHD, and NDD according to sociodemographic and exposure characteristics.
| VARIABLES | ASD N = 24 | ADHD N = 41 | NDD (ASD OR ADHD) N = 54 | |||
|---|---|---|---|---|---|---|
| N | (%) | N | (%) | N | (%) | |
| Child sex | ||||||
| Male | 18 | (8.1) | 28 | (12.6) | 39 | (17.5) |
| Female | 6 | (2.6) | 13 | (5.7) | 15 | (6.6) |
| p‑valuea | 0.010 | 0.012 | <0.001 | |||
| Belonging to indigenous peoples | ||||||
| Aymara | 6 | (3.5) | 11 | (6.4) | 15 | (8.8) |
| Other | 4 | (12.1) | 3 | (9.1) | 5 | (1.2) |
| No | 14 | (5.7) | 27 | (11.0) | 34 | (13.8) |
| p‑valuea | 0.099 | 0.274 | 0.250 | |||
| Mother’s or tutor’s education | ||||||
| 0–8 years | 1 | (3.3) | 1 | (3.3) | 1 | (3.3) |
| 9–12 years | 15 | (6.9) | 23 | (10.6) | 32 | (14.8) |
| ≥13 years | 8 | (3.9) | 17 | (8.4) | 21 | (10.3) |
| p‑valuea | 0.377 | 0.442 | 0.131 | |||
| Attending the School Integration Program | ||||||
| Yes | 19 | (17.3) | 32 | (29.1) | 40 | (36.7) |
| No | 5 | (1.5) | 9 | (2.8) | 14 | (4.3) |
| p‑valuea | <0.001 | <0.001 | <0.001 | |||
| Attendance at special school | ||||||
| Yes | 14 | (10.5) | 22 | (16.5) | 30 | (22.6) |
| No | 10 | (3.2) | 19 | (6.0) | 24 | (7.6) |
| p‑valuea | 0.001 | <0.001 | <0.001 | |||
| Screen exposure (day hours) | ||||||
| 0–2 | 7 | (5.8) | 12 | (9,9) | 15 | (12.4) |
| 3–10 | 17 | (5.2) | 29 | (8.8) | 39 | (11.9) |
| p‑valuea | 0.796 | 0.719 | 0.875 | |||
| Frequency of household pesticide use | ||||||
| Doesn’t use | 12 | (5.1) | 27 | (11.4) | 31 | (13.1) |
| At least once a year | 4 | (6.0) | 2 | (3.0) | 6 | (9.0) |
| Monthly | 4 | (4.9) | 8 | (9.8) | 10 | (12.2) |
| Weekly | 2 | (3.9) | 4 | (7.7) | 5 | (9.6) |
| Daily | 2 | (15.4) | 0 | (0.0) | 2 | (15.4) |
| p‑valuea | 0.512 | 0.217 | 0.861 | |||
| Father or mother beneficiary of Polymetal Law | ||||||
| Yes | 5 | (5.5) | 7 | (9.7) | 10 | (13.9) |
| No | 19 | (6.9) | 33 | (9.5) | 43 | (12.4) |
| Doesn’t know | 0 | (0.0) | 1 | (3.3) | 1 | (3.3) |
| p‑valuea | 0.431 | 0.658 | 0.286 | |||
[i] Note: ASD, autism spectrum disorder; ADHD, attention deficit hyperactivity disorder; NDD, neurodevelopmental disorders.
[ii] a Pearson’s chi‑square test and Fisher’s exact test were used for categorical variables.
Table 3
Description of urinary inorganic arsenic level corrected for creatinine according to sociodemographic and exposure variables.
| VARIABLES | URINARY IN‑AS (μG/G) | ||
|---|---|---|---|
| N | MEDIAN (P25th–P75th) | P‑VALUEa | |
| Child sex | 450 | 0.834 | |
| Female | 227 | 16.9 (12.0–24.2) | |
| Male | 223 | 17.0 (11.8–23.5) | |
| Age (years) | 450 | 0.041 | |
| 7–8 | 379 | 17.7 (12.2–24.3) | |
| 9–10 | 71 | 15.0 (11.5–21.4) | |
| Belonging to indigenous peoples | 450 | 0.022 | |
| No | 246 | 15.7 (11.2–22.4) | |
| Aymara | 171 | 18.7 (13.5–25.2) | |
| Other | 33 | 17.3 (12.7–24.7) | |
| Mother’s or tutor’s education | 450 | 0.002 | |
| 0–8 years | 30 | 21.6 (12.1–33.2) | |
| 9–12 years | 217 | 17.8 (12.7–26.0) | |
| ≥13 years | 203 | 15.3 (11.2–21.7) | |
| Number of household members | 450 | 0.375 | |
| 2–4 | 210 | 16.5 (11.7–22.9) | |
| 5–14 | 240 | 17.4 (12.1–24.6) | |
| 2–14b | Rho = 0.027 | 0.562 | |
| History of grade repetition | 450 | 0.612 | |
| No | 436 | 17.0 (12.0–23.9) | |
| Yes | 14 | 16.4 (14.0–31.9) | |
| Attending the School Integration Program | 450 | 0.302 | |
| No/Doesn’t know | 340 | 16.7 (12.0–23.4) | |
| Yes | 110 | 18.1 (12.1–26.0) | |
| Attendance at special school | 450 | 0.270 | |
| No | 317 | 16.3 (12.0–23.5) | |
| Yes | 133 | 18.2 (12.1–24.3) | |
| Screen exposure (day hours) | 450 | 0.399 | |
| 0–2 | 121 | 17.8 (13.3–22.8) | |
| 3–10 | 329 | 16.7 (12.0–23.9) | |
| 0–10b | Rho = −0.081 | 0.086 | |
| Frequency of household pesticide use | 450 | 0.033 | |
| Doesn’t use | 236 | 15.4 (11.7–21.6) | |
| At least once a year | 67 | 19.5 (13.7–25.9) | |
| Monthly | 82 | 19.4 (11.1–25.0) | |
| Weekly | 52 | 17.9 (13.0–24.3) | |
| Daily | 13 | 19.3 (13.3–27.2) | |
| Source of drinking water | 450 | 0.007 | |
| Bottled water | 382 | 16.7 (11.7–22.9) | |
| Public water network or water tanker | 66 | 18.9 (13.7–27.4) | |
| Well water | 2 | 60.5 (28.2–92.8) | |
| Source of water for cooking | 450 | 0.008 | |
| Bottled water | 44 | 15.5 (10.2–20.9) | |
| Public water network or water tanker | 399 | 16.9 (12.1–24.2) | |
| Well water | 7 | 27.4 (20.4–60.7) | |
| Paved floor in the house’s patio or front garden | 450 | 0.001 | |
| No | 72 | 20.4 (13.9–32.0) | |
| Yes | 378 | 16.5 (11.7–22.7) | |
| Paved road in front of the house | 449 | 0.061 | |
| No | 77 | 19.1 (13.3–28.2) | |
| Yes | 372 | 16.8 (11.9–23.1) | |
| Exposure to SHS in the last 72 h | 450 | 0.929 | |
| No | 370 | 17.4 (12.0–23.9) | |
| Yes | 80 | 15.9 (12.8–23.8) | |
| Father or mother beneficiary of Polymetal Law | 450 | 0.455 | |
| No/Doesn’t know | 378 | 17.0 (12.0–23.3) | |
| Yes | 72 | 17.1 (12.3–24.8) | |
| ASD reported by parents | 450 | 0.205 | |
| No | 426 | 16.9 (12.0–23.5) | |
| Yes | 24 | 21.6 (12.6–29.2) | |
| ADHD reported by parents | 450 | 0.659 | |
| No | 409 | 16.9 (12.1–23.5) | |
| Yes | 41 | 17.3 (11.8–27.3) | |
| NDD (ASD or ADHD) reported by parents | 450 | 0.423 | |
| No | 396 | 16.9 (12.0–23.2) | |
| Yes | 54 | 18.6 (12.1–26.8) | |
[i] Note: P25th–P75th percentile; ASD, autism spectrum disorder; ADHD, attention deficit hyperactivity disorder; NDD, neurodevelopmental disorders; SHS, secondhand smoke.
[ii] a Wilcoxon (Mann–Whitney) test for dichotomous variables and Kruskal–Wallis test for categorical variables.
[iii] b Spearman correlation between continuous variables (presented categorized in the table).
Table 4
Bivariate analysis between the prevalence of ASD, ADHD, and NDD according to sociodemographic and exposure variables.
| SOCIODEMOGRAPHIC VARIABLES | ASD | ADHD | NDD |
|---|---|---|---|
| OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| Child sex | |||
| Female | Reference | Reference | Reference |
| Male | 3.23 (1.26, 8.31) | 2.36 (1.19, 4.69) | 3.00 (1.60, 5.61) |
| Belonging to indigenous peoples | |||
| No | Reference | Reference | Reference |
| Aymara | 0.60 (0.23, 1.60) | 0.56 (0.27, 1.16) | 0.60 (0.32, 1.14) |
| Other | 2.29 (0.70, 7.41) | 0.81 (0.23, 2.84) | 1.11 (0.40, 3.08) |
| Mother’s or tutor’s education | |||
| ≥13 years | Reference | Reference | Reference |
| 9–12 years | 1.81 (0.75, 4.37) | 1.30 (0.67, 2.51) | 1.50 (0.83, 2.70) |
| 0–8 years | 0.84 (0.10, 6.97) | 0.38 (0.05, 2.94) | 0.30 (0.04, 2.31) |
| History of grade repetition | |||
| No | Reference | Reference | Reference |
| Yes | 1 | 2.86 (0.76, 10.69) | 2.06 (0.56, 7.63) |
| Attending the School Integration Program | |||
| No/Doesn´t know | Reference | Reference | Reference |
| Yes | 13.99 (5.08, 38.49) | 15.09 (6.92, 32.90) | 13.31 (6.87, 25.77) |
| Attendance at special school | |||
| No | Reference | Reference | Reference |
| Yes | 3.61 (1.56, 8.35) | 3.11 (1.62, 5.96) | 3.56 (1.99, 6.36) |
| Type of school | |||
| Private or semi‑private school | Reference | Reference | Reference |
| Public | 1.71 (0.75, 3.91) | 2.06 (1.08, 3.94) | 1.95 (1.10, 3.45) |
| Screen exposure (day hours) | |||
| 0–2 | Reference | Reference | Reference |
| 3–10 | 0.89 (0.36, 2.20) | 0.88 (0.43, 1.78) | 0.95 (0.50, 1.79) |
| Frequency of household pesticide use | |||
| At least once a year | Reference | Reference | Reference |
| Monthly | 0.81 (0.19, 3.36) | 3.51 (0.72, 17.14) | 1.41 (0.49, 4.11) |
| Weekly | 0.63 (0.11, 3.58) | 2.71 (0.48, 15.40) | 1.08 (0.31, 3.76) |
| Daily | 2.86 (0.47, 17.57) | 1 | 1.85 (0.33, 10.37) |
| Source of drinking water | |||
| Bottled water | Reference | Reference | Reference |
| Public water network or water tanker | 1.57 (0.56, 4.35) | 1.21 (0.51, 2.87) | 1.18 (0.55, 2.55) |
| Well water | 1 | 1 | 1 |
| Source of water for cooking | |||
| Bottled water | Reference | Reference | Reference |
| Public water network or water tanker | 1.23 (0.28, 5.40) | 1.44 (0.43, 4.87) | 1.43 (0.49, 4.18) |
| Well water | 1 | 1 | 1 |
| Paved floor in the house’s patio or front garden | |||
| No | Reference | Reference | Reference |
| Yes | 1.35 (0.39, 4.66) | 0.92 (0.39, 2.16) | 1.11 (0.50, 2.46) |
| Paved road in front of the house | |||
| No | Reference | Reference | Reference |
| Yes | 0.78 (0.28,– 2.14) | 1.23 (0.50, 3.03) | 1.04 (0.49, 2.23) |
| Exposure to SHS in the last 72 h | |||
| No | Reference | Reference | Reference |
| Yes | 1.59 (0.61, 4.13) | 1.34 (0.61, 2.93) | 1.38 (0.69, 2.75) |
| Father or mother beneficiary of Polymetal Law | |||
| No/Doesn’t know | Reference | Reference | Reference |
| Yes | 1.41 (0.51, 3.91) | 1.09 (0.46, 2.56) | 1.22 (0.58, 2.56) |
| Current urinary In‑As concentration corrected by creatinine μg/g | |||
| In‑As < 35 μg/g | Reference | Reference | Reference |
| In‑As ≥ 35 μg/g | 1.12 (0.25, 4.97) | 2.91 (1.18, 7.18) | 2.04 (0.84, 4.93) |
[i] Note: Simple logistic regression was used; ASD, autism spectrum disorder; ADHD, attention deficit hyperactivity disorder; NDD, neurodevelopmental disorders; SHS, secondhand smoke; OR, odds ratio; CI, confidence interval.
Table 5
Association between arsenic exposure and ASD, ADHD, and NDD according to parents’ reports.
| MODEL 1b | MODEL 2c | MODEL 3d | ||||
|---|---|---|---|---|---|---|
| ARSENICa | OR (95% CI) | P‑VALUE | OR (95% CI) | P‑VALUE | OR (95% CI) | P‑VALUE |
| Autism spectrum disorder (ASD) | ||||||
| In‑As < 35 μg/g | Reference | Reference | Reference | |||
| In‑As ≥ 35 μg/g | 1.12 (0.25, 4.97) | 0.882 | 1.16 (0.25, 5.42) | 0.846 | 1.36 (0.28, 6.49) | 0.701 |
| AIC | 191.373 | 194.638 | 189.827 | |||
| Attention deficit hyperactivity disorder (ADHD) | ||||||
| In‑As < 35 μg/g | Reference | Reference | Reference | |||
| In‑As ≥ 35 μg/g | 2.91 (1.18, 7.18) | 0.020 | 3.61 (1.38, 9.45) | 0.009 | 3.85 (1.44, 10.29) | 0.007 |
| AIC | 274.011 | 276.164 | 273.655 | |||
| Neurodevelopmental disorders (NDD) | ||||||
| In‑As < 35 μg/g | Reference | Reference | Reference | |||
| In‑As ≥ 35 μg/g | 2.04 (0.84, 4.93) | 0.115 | 2.64 (1.03, 6.78) | 0.043 | 2.93 (1.11, 7.75) | 0.030 |
| AIC | 332.023 | 329.177 | 320.135 | |||
[i] Note: Multiple logistic regression was used; OR, odds ratio; CI, confidence interval; AIC, Akaike information criterion.
[ii] a Urinary In‑As concentration corrected for creatinine μg/g.
[iii] b Model 1, Crude.
[iv] c Model 2, Adjusted for socioeconomic level (mother’s or tutor’s education and the number of people living in the household).
[v] d Model 3, Adjusted for socioeconomic level (mother’s or tutor’s education and the number of people living in the household), sex, and belonging to indigenous peoples.