Table 1. Descriptive characteristics of the study samples.
| Microbiome Analysisa | Imaging Analysisb | Microbiome & Imaging Analysisc | |||||||
|---|---|---|---|---|---|---|---|---|---|
| ADHD (n = 19) |
Controls (n = 77) | p | ADHD (n = 24) | Controls (n = 63) | p | ADHD (n = 6) | Controls (n = 22) | p | |
| Age in Years (SD) | 19.5 (2.5) | 27.1 (14.3) | .024 | 20.3 (3.7) | 21.3 (3.4) | n.s. | 18.6 (2.5) | 21.1 (3.3) | n.s. |
| BMI (SD) | 23.8 (4.1) | 23.0 (3.2) | n.s. | 22.8 (3.5) | 22.7 (2.9) | n.s. | 22.1 (4.4) | 23.4 (3.7) | n.s. |
| % Malesd | 68.4 | 53.2 | n.s. | 75 | 61.9 | n.s. | 66.7 | 59.1 | n.s. |
| Mean Inattention Symptoms (SD) | 6.5 (2.1) | 0.7 (1.4)e | < .001 | 6.2 (1.5) | 0.5 (1.0) | < .001 | 6.0 (1.6) | 0.7 (1.3) | < .001 |
| Mean Hyperactivity Symptoms (SD) | 4.4 (2.1) | 0.6 (1.1)e | < .001 | 4.2 (2.4) | 0.7 (1.2) | < .001 | 5.0 (1.4) | 0.7 (1.2) | < .001 |
| Mean Total Symptoms (SD) | 11.0 (2.9) | 1.3 (2.4)e | < .001 | 10.3 (3.0) | 1.2 (2.1) | < .001 | 11.0 (1.8) | 1.4 (2.4) | < .001 |
| Mean Number of Reads (SD) | 3893 (783) | 3760 (1038) | n.s. | N/A | N/A | N/A | N/A | ||
| Total Number of Reads | 73969 | 289492 | N/A | N/A | N/A | N/A | |||
| →Assigned at Phylum | 73876 (99.9%) | 289117 (99.9%) | n.s. | N/A | N/A | N/A | N/A | ||
| →Assigned at Genus | 61657 (83.4%) | 230370 (79.6%) | n.s. | N/A | N/A | N/A | N/A | ||
| Mean Number of OTU (SD) | 389 (103) | 429 (157) | n.s. | N/A | N/A | N/A | N/A | ||
| Total Number of OTU | 7041 | 33048 | N/A | N/A | N/A | N/A | |||
| Mean Shannon index f | 5.3 | 5.2 | n.s. | N/A | N/A | N/A | N/A | ||
| Mean Chao index f | 604.5 | 579.7 | n.s. | N/A | N/A | N/A | N/A | ||
a Four sibling pairs were included in the ADHD group, ten sibling pairs and two trio’s in the control group. Four ADHD cases had one sibling in the control group. No BMI was available for four control subjects.
b Four sibling pairs were included in the ADHD group, 13 sibling pairs and six trio’s in the control group. Nine ADHD cases had one sibling in the control group; one ADHD case had two siblings in the control group. No BMI was available for two ADHD and three control subjects. Initially, 95 participants performed the reward anticipation task during fMRI. However, four ADHD participants and four control participants were excluded from the fMRI analyses: five were excluded due to excessive (i.e. > 6 mm) movement (three ADHD + two controls), one due to an incomplete data set (ADHD), one due to too many errors (48%, control), and one due to extensive signal drop-out (control).
c One sibling pair was included in the ADHD group, eight sibling pairs in the control group. One ADHD case had one sibling in the control group. No BMI was available for two control subjects.
d Differences in gender between the groups were tested with chi-square or Fisher’s exact test, as appropriate. All other differences were tested with an independent t-test.
e No symptoms were available for n = 39 control subjects.
f Metrics for alpha diversity; reads were down-sampled to 1126 reads per sample, average of 4 trials, for the calculation of this diversity metric.
N/A: Not Available; BMI: Body Mass Index; OTU: Operational Taxonomic Unit; SD: Standard Deviation; n.s.: not significant.