TABLE 4.
Regression of change in cognitive performance on change in blood measures among nonanemic Rwandan female college students in the efficacy trial, irrespective of treatment assignment1
| Ferritin2 |
Transferrin receptor |
Body iron |
|||||||
| Variables by task | Intercept | β | R2 | Intercept | β | R2 | Intercept | β | R2 |
| SRT task RT | −11.3 | 7.1 | 0.00 | −8.7 | −2.1 | 0.01 | −11.1 | 2.1 | 0.00 |
| GNG task RT | −27.5 | −19.5 | 0.03 | −33.4 | −2.2 | 0.01 | −30.4 | −3.4 | 0.01 |
| ANT RTs | |||||||||
| 0 Cues | −24.4 | −69.7** | 0.14# | −46.3 | −2.4 | 0.00 | −32.4 | −14.0* | 0.09 |
| 2 Cues | −124.7 | −50.0 | 0.06 | −140.9 | 3.2 | 0.00 | −127.6 | −12.8 | 0.06 |
| Alerting | 93.9 | 0.9 | 0.00 | 95.5 | −6.4 | 0.03 | 90.0 | 4.1 | 0.01 |
| Center cue | −40.3 | −52.2 | 0.05 | −57.5 | 0.2 | 0.00 | −44.4 | −12.6 | 0.04 |
| Spatial cues | −157.2 | −91.0*** | 0.17# | −187.8 | 3.3 | 0.00 | −163.9 | −22.3*** | 0.15 |
| Orienting | 116.7 | 38.5 | 0.05 | 129.9 | −3.1 | 0.01 | 119.2 | 9.7 | 0.05 |
| Consistent flankers | −42.2 | −50.5* | 0.08 | −58.0 | 0.7 | 0.00 | −46.4 | −11.8+ | 0.07 |
| Inconsistent flankers | −98.4 | −84.4*** | 0.17 | −126.9 | 9.9 | 0.05 | −98.2 | −26.4*** | 0.26# |
| Conflict | −63.9 | −19.3 | 0.01 | −71.4 | 5.7 | 0.02 | −62.2 | −7.8 | 0.03 |
| CRT | |||||||||
| Sensitivity (d’) | 0.3 | 0.7* | 0.08 | 0.5 | 0.0 | 0.00 | 0.3 | 0.16* | 0.07 |
| PCC | 44.7 | 23.9 | 0.02 | 52.9 | −2.5 | 0.00 | 44.9 | 7.4 | 0.04 |
| RTs | |||||||||
| New items | 17.1 | −171.1** | 0.13 | −43.5 | 21.4 | 0.04 | 11.0 | −48.1*** | 0.16# |
| Old items | 40.1 | −168.8*** | 0.23# | −16.0 | 3.8 | 0.00 | 28.0 | −42.2*** | 0.22 |
| Bias (c) | 0.1 | −0.1 | 0.01 | 0.1 | 0.0 | 0.00 | 0.1 | 0.0 | 0.00 |
| SMS task RTs | |||||||||
| Intercept | |||||||||
| New | 10.6 | −223.8*** | 0.16# | −61.5 | −6.0 | 0.00 | −13.3 | −47.4** | 0.11 |
| Old | 3.9 | −221.5*** | 0.17# | −67.9 | −4.3 | 0.00 | −19.5 | −47.3** | 0.12 |
| Slope | |||||||||
| New | 4.0 | −20.1 | 0.04 | −3.0 | 1.8 | 0.01 | 3.3 | −5.6 | 0.05 |
| Old3 | 2.5 | −18.8 | 0.04 | −3.7 | 0.2 | 0.00 | 1.0 | −4.5 | 0.03 |
Nonanemic was defined as hemoglobin ≥120 g/L (n = 84). +P < 0.1; *P < 0.05; **P < 0.01; ***P < 0.001 compared with an intercept-only model, χ2 test; individual predictors were also tested. #These were the “best” models, which predicted ≥10% of the variance in the outcome and were significant (P ≤ 0.05) compared with the intercept-only model based on a χ2 test. ANT, attentional network task; CRT, cued recognition task; GNG, go/no-go; PCC, percentage change in capacity; RT, reaction time; SMS, Sternberg memory search; SRT, simple reaction time.
Ferritin was log-transformed.
The “best” model for SMS RT, slope, old items used change in hemoglobin as a predictor.