Table 5 Systematic Review Study Characteristics
Lead Author, Year | Country (Cohort) | N (%males) | Neuro-toxicant | Compound | Biomarker | Median of Exposure (ppb) | Outcome Measure | Interpretation | Reason Excluded from Meta-Analysis |
|---|---|---|---|---|---|---|---|---|---|
Baghurst, 1992 [56] | Australia (Port Pirie Cohort Study) | 494 (N/A) | Lead | N/A | Lifetime average blood up to 3 years | 122.0–282.0*a | FSIQ on WISC-R at 7 years | The negative association between lead exposure and FSIQ was more pronounced in females | No standard error or p-value to calculate effect size |
Berghuis, 2018 [51] | Netherlands (DACE Study) | 35–40 (~ 54.5) | PCB PBDE | ΣOH-PCBsc BDE-47 | 2nd/3rd trimester serum 2nd/3rd trimester serum | 0.4 0.9 | FSIQ, PRI, and VCI on WISC-III-NL at 13–15 years | Positive association between ΣOH-PCBs and VCI and FSIQ in females. Negative association between BDE-47 and FSIQ in females | No other combinable study of OH-PCBs or BDE-47 (only data for females) |
Castorina, 2017 [58] | USA (CHAMACOS) | 248–275 (~ 54.8) | OPP OPP OPP | BDCIPP DPHP ip-PPP | 2nd trimester urine 2nd trimester urine 2nd trimester urine | 0.4 0.9 0.3 | FSIQ, PRI, VCI on WISC-IV at 7 years | No significant differences between the sexes | No data available |
Chen, 2014 [102] | USA (HOME) | 190 (44.0) | PBDE | BDE-47 | 2nd trimester blood | 18.9 | FSIQ on WPPSI-III at 5Â years | No significant differences between the sexes | Not enough combinable date to meta-analyze BDE-47 |
Choi, 2021 [100] | Norway (MoBA, Preschool ADHD Sub-Study) | 310 (56.9) | Phthalate Phthalate Phthalate Phthalate Phthalate Phthalate | MBzP, MiBP, MnBP, MEP, ∑DEHPd ∑DiNPe | 2nd trimester urine 2nd trimester urine 2nd trimester urine 2nd trimester urine 2nd trimester urine 2nd trimester urine | 5.45b 19.64b 21.70b 129.71b 0.30b 0.02b | Verbal and non-verbal WM on SB5 at 3.5 years | The negative association between MiBP, MnBP, and MEP and non-verbal WM was more pronounced in females | Non-combinable outcome measure (i.e., verbal, and nonverbal WM) |
Damm, 1993 [59] | Denmark (N/A) | 141–162 (45.4–46.9) | Lead | N/A | Shed deciduous teeth at 6 years | Low: < 5,000 High: > 18,700 | FSIQ, PIQ, VIQ on the Danish version of the WISC at 8 and 15 years | Females were better at coping with lead-related deficits in PIQ compared to males | No data available |
Davidson, 2006 [62] | Republic of Seychelles (SCDS) | 711 (N/A) | Mercury Mercury Mercury | N/A | Maternal hair at delivery Hair at 5.5Â years Hair at 5.5Â years | 6800.0a 6500.0a 6100.0a | GCI on MSCA at 5.5Â years and FSIQ on WISC-III at 8.9Â years | Positive association between postnatal mercury exposure and global cognition in males | No data available for prenatal exposure. Not enough combinable data to meta-analyze postnatal exposure |
Davidson, 2004 [61] | Republic of Seychelles (SCDS) | 711 (N/A) | Mercury | N/A | Maternal hair at delivery | 5900.0 | GCI on MSCA at 5.5Â years | No significant differences between the sexes | No data available |
Davidson, 1998 [60] | Republic of Seychelles (SCDS) | 711 (N/A) | Mercury Mercury | N/A | Maternal hair at delivery Hair at 5.5Â years | 6800.0a 6500.0a | GCI on MSCA at 5.5Â years | No significant differences between the sexes | No data available |
Ernhart, 1989 [65] | USA (N/A) | 146–169 (N/A) | Lead Lead | N/A | Cord blood Maternal blood at delivery | 58.9a 65.0a | FSIQ, PIQ, and VIQ on WPPSI at 4 years 10 months | No significant differences between the sexes | No data available |
Factor-Litvak, 2014 [67] | USA (CCCEH) | 328 (47.3) | Phthalate Phthalate Phthalate Phthalate Phthalate Phthalate | MnBP MBzP MEHHP MEHP MEP MiBP | 3rd trimester urine 3rd trimester urine 3rd trimester urine 3rd trimester urine 3rd trimester urine 3rd trimester urine | 38.0 14.4 21.8 4.9 141.5 9.2 | FSIQ, PRI, and VCI on WISC-IV at 7Â years | No significant differences between the sexes | No measure of overall DEHPs |
Freire, 2018 [52] | Spain (INMA) | 302 (71.5) | Lead Mercury | N/A | Placenta at birth Placenta at birth |  < 6.5 0.025 | GCI on MSCA at 4–5 years | The negative association between mercury and GCI is more pronounced in males | Same cohort, exposure, and outcome as Llop, 2017 |
Furlong, 2017 [68] | USA (The Mount Sinai Children’s Environmental Health Center) | 141 (51.0) | OPP OPP | ∑DEPf ∑DMPg | 2nd/3rd trimester urine 2nd/3rd trimester urine | 2.5 4.7 | FSIQ, VIQ and PIQ on the WPPSI-III at 6 years and FSIQ, PRI, VCI,on the WISC-IV between 7–9 years | No significant differences between the sexes | No data available |
Golding, 2017 [70] | UK (ALSPAC) | 1758–1759 (49.9) | Mercury | N/A | 1st trimester blood | 1.86 | FSIQ, PIQ, and VIQ on WISC-III at 8 years | No significant differences between the sexes | Non-linear regression techniques (logistic regression) |
Huang, 2015 [72] | Taiwan (TMICS) | 73–100 (N/A) | Phthalate Phthalate Phthalate Phthalate Phthalate | MMP MEP MBP MBzP ΣMEHPh | 3rd trimester urine, urine at 2–3, and urine at 5–6 years | 49,840b 66,610b 77,870b 17,430b 58,690b | FSIQ on WPPSI-R at 5 years, WISC-III at 8 years and WISC-IV at 11 years | No significant differences between the sexes | No data available |
Huang, 2007 [71] | Republic of Seychelles (SCDS) | 643 (N/A) | Mercury | N/A | Maternal hair at delivery | 5,990 – 8,790a | FSIQ on WISC-III at 9 years | No significant differences between the sexes | No data available |
Ikeno, 2018 [74] | Japan (N/A) | 141 (46.8) | PCBs PCBs PCBs | Non-Ortho Mono-Ortho Coplanar | 2nd trimester blood 2nd trimester blood 2nd trimester blood | 0.059 8.029 8.101 | MPS on the K-ABC at 3.5Â years | Strong negative association for total non-ortho PCBs and MPS in males | No other combinable study of PCBs |
Jacobson, 2002 [75] | USA (N/A) | 124–158 (N/A) | PCBs PCBs PCBs | Total PCBs Total PCBs Total PCBs | Cord blood Maternal blood at birth Maternal milk at 0.5–4.5 months | 2.6a 5.7a 829.7a | GCI, VS, and PPS on MSCA at 4 years and FSIQ, VCI, and PRI on WISC-R at 11 years | At 11 years, the negative effects of cord blood PCBs on FSIQ and PRI were more pronounced among males | No standard-error or exact p-value to calculate effect size |
Kyriklaki, 2016 [78] | Greece (Rhea Study) | 695 (51.6) | PCBs | Total PCBs | 1st trimester blood | 0.32 | GCI on MSCA at 4Â years | No significant differences between the sexes | No data available |
McBride, 1982 [81] | Australia (N/A) | 84–88 (N/A) | Lead | N/A | Blood at 4–5 years | 2629.4b | VIQ on the PPVT at 4–5 years | No interpretation made | Non-linear regression technique (mean scores) |
McMichael, 1994 [82] | Australia (Port Pirie Cohort Study) | 262 (43.3) | Lead | N/A | Incisor teeth at 6Â years | 8600b | FSIQ, PIQ, and VIQ on WISC-R at 7Â years | No significant differences between the sexes | No data available |
McMichael, 1988 [84] | Australia (Port Pirie Cohort Study) | 474–534 (NA) | Lead Lead Lead Lead Lead Lead Lead | N/A | 1st trimester blood Cord blood Blood at 6 months Blood at 15 months Blood at 2 years Blood at 3 years Blood at 4 years | 91.00b 95.00b 144.7b 208.9b 213.0b 194.4b 163.3b | GCI and PPS, on MSCA at 4 years | No significant differences between the sexes | No data available |
Min, 2009 [85] | USA (N/A) | 273–278 (~ 48) | Lead | N/A | Blood at 4 years | 61.0 | FSIQ, PIQ and VIQ, on WPPSI-R at 4 years and FSIQ, PRI, and VCI, on WISC-IV at 9 and 11 years | No significant differences between the sexes | No data available |
Myers, 2003 [86] | Republic of Seychelles (SCDS) | 643 (N/A) | Mercury | N/A | Maternal hair at delivery | 6900.0a | FSIQ on WISC-III at 9Â years | No significant differences between the sexes | No data available |
Myers, 1995 [87] | Republic of Seychelles (SCDS) | 217 (N/A) | Mercury | N/A | Maternal hair at delivery | 7100.0 | GCI and PPS on MSCA at 5.5Â years | No significant differences between the sexes | No data available |
Palumbo, 2000 [89] | Republic of Seychelles (SCDS) | 708–711 (N/A) | Mercury Mercury | N/A | Maternal hair at delivery Hair at 5.5 years | 6800.0a 6500.0a | PPS and VS on MSCA at 5.5 years | No significant differences between the sexes | No data available |
Rauh, 2011 [91] | USA (CCCEH) | 265 (44.2) | OPP | CPF | Cord blood | 0.003a | FSIQ, PRI, VCI, on WISC-IV at 7Â years | No significant differences between the sexes | No data available |
Ris, 2004 [92] | USA (Cincinnati Lead Study) | 195 (53.6) | Lead | N/A | Maternal blood Blood samples up to 5 years | Range: 50.0–270.0 | Learning/IQ factor derived from WRAT-3 and WISC-III at 15–17 years | No significant differences between the sexes | No data available |
Schnaas, 2000 [93] | Mexico (Mexico City Prospective Lead Study) | 112 (47.3) | Lead | N/A | Blood at 6–18 months Blood at 24–36 months Blood at 42–54 months | 101b 97b 84b | GCI on MSCA at 3, 3.5, 4, 4.5 and 5 years | No significant differences between the sexes | No data available |
Tatsuta, 2014 [94] | Japan (TSCD) | 387 (52.2) | PCBs | 9CBs | Cord blood | 0.22 | MPS on K-ABC at 3.5Â years | The negative association between the MPS and 9CBs was more pronounced in males | No other combinable study of 9CBs |
Vuong, 2017 [98] | USA (HOME) | 208 (44.7) | PBDE | ∑PBDEsi | Blood at 1 year Blood at 2 years Blood at 3 years Blood at 5 years | 118.1b 127.7b 100.5b 64.6b | FSIQ on WISC-IV at 8 years | No significant differences between the sexes | No other combinable study of postnatal PBDEs |
Zhu, 2020 [99] | China (MABC) | 1865–2128 (~ 52.0) | Phthalate Phthalate Phthalate Phthalate Phthalate Phthalate Phthalate | MMP MBP MBzP MEHHP MEHP MEOHP MEP | Mean of three urines Mean of three urines Mean of three urines Mean of three urines Mean of three urines Mean of three urines Mean of three urines | N/A N/A N/A N/A N/A N/A N/A | FSIQ, VCI, and VSI on WPPSI-IV (Chinese version) between 3 to 6 years | Negative association between MBP and VSI and FSIQ in males, whereas in girls’ results were attenuated near zero. Positive association between MEHP and FSIQ in males and MBzP and VCI in males/ | No measure of overall DEHPs |