Table 1.
22-year summary statistics for covariates and neurodevelopmental endpoints among participants with at least one outcome: Seychelles Child Development Study Main cohort.
| Outcomes and Relevant Covariates† | N | Mean (SD) or % | Median |
|---|---|---|---|
| MeHg Exposure (ppm) | |||
| Prenatal | 571 | 6.83 (4.51) | 6.03 |
| Recent postnatal (22 yr) | 537 | 5.17 (4.02) | 4.40 |
| Covariates | |||
| Child Sex (female = 1, %) | |||
| Female | 301 | 52.7% | |
| Male | 270 | 47.3% | |
| Child Life course stress | 571 | 3.16 (1.83) | 3.00 |
| Child full scale IQ at 9 years | 532 | 80.48 (11.34) | 81.00 |
| Family Hollingshead SES at 9 years | 522 | 24.75 (10.57) | 23.25 |
| Maternal IQ | 510 | 79.91 (15.17) | 77.00 |
| Profile of Mood States (POMS) | |||
| Negative affect ↓ | 560 | 37.68 (19.30) | 36.50 |
| Positive affect ↑ | 560 | 69.56 (16.97) | 72.00 |
| Boston Naming Test (BNT) total score ↑ | 567 | 40.66 (7.20) | 41.00 |
| CANTAB | |||
| Reaction Time (RT) | |||
| 5-choice accuracy ↑ | 564 | 14.87 (0.44) | 15.00 |
| 5-choice reaction timea | 564 | 370.77 (70.24) | 360.33 |
| Intra/Extra dimensional shift (IED) | |||
| Total errors adjusted ↓ | 564 | 42.31 (26.76) | 49.00 |
| Stages completed ↑ | 564 | 7.92 (1.21) | 8.00 |
| Pre-ED errors ↓ | 564 | 7.79 (5.76) | 6.00 |
| Completed stages errors ↓ | 564 | 14.37 (10.45) | 11.00 |
| Paired Associate Learning (PAL) | |||
| Stages completed ↑ | 564 | 4.89 (0.37) | 5.00 |
| Total errors adjusted ↓ | 564 | 20.04 (21.08) | 14.00 |
| Stages completed on first trial ↑ | 564 | 3.01 (0.72) | 3.00 |
| Delayed Match to Sample (DMS) | |||
| % correct 0 ms delay ↑ | 564 | 85.50 (15.64) | 80.00 |
| % correct 4 ms delay ↑ | 564 | 85.28 (17.51) | 80.00 |
| % correct 12 ms delay ↑ | 564 | 83.09 (18.65) | 80.00 |
| % correct simultaneous ↑ | 564 | 97.87 (6.72) | 100.00 |
| Rapid Visual Information Processing (RVP) | |||
| Total misses ↓ | 564 | 12.37 (5.28) | 13.00 |
| Total false alarms ↓ | 564 | 8.10 (20.62) | 2.00 |
| Mean latency ↓ | 562 | 462.83 (149.39) | 423.04 |
| Spatial Working Memory (SWM) | |||
| Strategy ↓ | 564 | 35.33 (3.92) | 35.00 |
| Between errors ↓ | 564 | 32.24 (21.07) | 27.00 |
| Within errors ↓ | 564 | 1.67 (3.18) | 1.00 |
| Total errors ↓ | 564 | 32.86 (21.29) | 28.00 |
| Stockings of Cambridge (SOC) | |||
| Mean moves for 3 move problem ↓ | 564 | 3.39 (0.58) | 3.00 |
| Mean moves for 4 move problem ↓ | 564 | 5.62 (1.04) | 5.50 |
| Mean moves for 5 move problem ↓ | 563 | 7.16 (1.47) | 7.00 |
| Healthy Behaviors (HB) (%) ↓ | |||
| Substance Abuse | 555 | 100.0% | |
| 0 | 84 | 15.1% | |
| 1 | 142 | 25.6% | |
| 2 | 133 | 24.0% | |
| 3 | 96 | 17.3% | |
| 4+ | 100 | 18.0% | |
| Mental Healthb | 555 | 100.0% | |
| 0 | 279 | 50.3% | |
| 1 | 106 | 19.1% | |
| 2 | 73 | 13.2% | |
| 3+ | 97 | 17.5% | |
| Antisocial | 555 | 100.0% | |
| 0 | 369 | 66.5% | |
| 1 | 116 | 20.9% | |
| 2+ | 70 | 12.6% | |
| Injury | 555 | 100.0% | |
| 0 | 475 | 85.6% | |
| 1 | 52 | 9.4% | |
| 2+ | 28 | 5.0% |
†
RT: simple; IED: total trials adjusted; PAL: total trials adjusted not included because of their high correlation with other measures included in the table; arrows indicate direction of better performance (↓ = lower scores are better; ↑ = higher scores are better)
a
RT scores indicate response speed and not necessarily better or worse.
b
Rounding results in the sum of the percentages to be 100.1%