Table 1. Differences between ADHD and control subjects.

Statistical difference (P-value) was computed according to the distribution by Fisher’s exact test (categorical variables), Student’s t-test (age, ASRS total sum, and serum ferritin), or Mann-Whitney U-test (serum iron).

ADHD: attention-deficit/hyperactivity disorder; ASRS: adult ADHD self-report scale

	ADHD Occurrence (%) or Median; Mean (95% CI)	Controls Occurrence (%) or Median; Mean (95% CI)	P-Value
Gender: women/men	57% / 43%	75% / 25%	0.429
Age (y)	39.2 y; 38.2 (33 to 42)	34.6 y; 34.6 (28 to 41)	0.308
ASRS (part A) ≥ 4	70 %	0 %	0.003
ASRS (total sum)	64; 62.8 (56.7 to 68.9)	34.5; 37 (31.3 to 42.7)	<0.001
Serum iron (umol/L)	12.6 (9.4 to 15.8)	17.9 (13.6 to 22.2)	0.026
Serum ferritin (ug/L)	80.6 (26.6 to 134.6)	86 (47.6 to 124.4)	0.851