Potential role of pre- and postnatal testosterone levels in attention-deficit/hyperactivity disorder: is there a sex difference?

Figures & data

Table 1 Characteristics of patients with ADHD and comparison of male and female patients

Variables	Males (n=158)	Females (n=42)	Statistical valuesa	P-value
Age (years)	8.8±2.1	8.3±1.7	t=1.199	0.232
Height (cm)	133.7±13.9	126.7±9.8	t=3.082	0.002**
Weight (kg)	33.5±11.1	27.8±9.8	t=3.066	0.002**
Body mass index (kg/m^2)	18.3±3.2	16.9±3.6	t=2.338	0.023*
ADHD subtypes, n (%)
Inattentive type	42 (26.6)	18 (42.9)	χ^2=4.185	0.041*
Hyperactive/impulsive or combined type	116 (73.4)	24 (57.1)
Comorbidities, n (%)
Oppositional defiant disorder	31 (19.6)	4 (9.5)	χ^2=2.343	0.126
Conduct disorder	2 (1.3)	0 (0)	χ^2=0.537	0.464
Tic disorders	14 (8.9)	4 (9.5)	χ^2=0.018	0.894
Sleep disorders	4 (2.5)	0 (0)	χ^2=1.085	0.298
Anxiety disorders	7 (4.4)	2 (4.8)	χ^2=0.008	0.927
WISC-IV
Full Scale Intelligence Quotient	95.5±12.2	91.9±12.7	t=1.705	0.090
Verbal Comprehension Index	99.6±11.6	94.9±11.9	t=2.314	0.022*
Perceptual Reasoning Index	95.8±15.1	92.9±13.7	t=1.126	0.261
Working Memory Index	96.6±13.4	94.1±13.9	t=1.046	0.297
Processing Speed Index	93.8±14.5	91.6±13.5	t=0.877	0.381
Clinical measures
SNAP-IV parent form (I)	15.0±5.3	16.2±4.8	t=−1.329	0.185
SNAP-IV parent form (H)	13.4±5.8	12.1±6.3	t=1.241	0.216
SNAP-IV parent form (O)	10.9±5.7	9.9±5.3	t=1.006	0.315
SNAP-IV teacher form (I)	14.3±6.1	13.0±6.1	t=1.188	0.236
SNAP-IV teacher form (H)	12.1±7.2	6.8±6.6	t=4.369	<0.001***
SNAP-IV teacher form (O)	7.8±6.2	4.4±4.7	t=3.332	0.001**
Indices of CPT
Confidence Index	58.6±21.0	53.4±23.5	t=1.426	0.155
Omission	59.1±26.6	58.3±24.1	t=0.173	0.863
Commission	50.4±9.9	51.5±9.4	t=−0.652	0.515
Hit reaction time	54.7±12.1	56.5±13.0	t=−0.817	0.415
Detectability	51.2±9.0	52.7±10.9	t=−0.884	0.378

Notes: Data are expressed as mean ± SD or n (%).

a Statistical values are expressed as t-value or χ²:

* P<0.05,

** P<0.01,

*** P<0.001.

Abbreviations: ADHD, attention-deficit/hyperactivity disorder; CPT, Conners’ Continuous Performance Test; H, hyperactivity/impulsivity scores; I, inattention scores; O, oppositional scores; SD, standard deviation; SNAP-IV, Swanson, Nolan, and Pelham – Version IV Scale for ADHD; WISC-IV, Wechsler Intelligence Scale for Children – Fourth Edition.

Table 2 Ratios of 2D/4D and salivary testosterone levels between sex and ADHD subtypes and comorbidities among ADHD patients

Variables	2D/4D ratio			Salivary testosterone
	Mean ± SD (%)	t	P-value	Mean ± SD (pg/mL)	t	P-value
Sex
Males (n=158)	96.1±4.7	0.275	0.784	54.2±86.1	2.043	0.043*
Females (n=42)	95.9±4.3			34.6±43.5
ADHD subtypes
Inattentive type (n=60)	97.0±4.5	1.868	0.063	43.2±55.3	−0.798	0.426
H/I or combined type (n=140)	95.7±4.6			53.0±87.8
ODD or conduct disorder
With (n=36)	94.6±6.0	−2.145	0.033*	53.7±118.7	0.298	0.766
Without (n=164)	96.4±4.2			49.3±68.4
Tic disorders
With (n=18)	96.1±4.8	−0.023	0.982	30.9±42.8	−1.075	0.284
Without (n=182)	96.1±4.6			52.0±82.0
Anxiety disorders
With (n=9)	95.4±4.2	−0.455	0.650	95.8±111.3	1.775	0.077
Without (n=191)	96.1±4.6			47.9±77.3

Notes:

* P<0.05.

Abbreviations: 2D/4D ratio, ratio of the length of the right index finger (2D) to that of the right ring finger (4D); ADHD, attention-deficit/hyperactivity disorder; H, hyperactivity/impulsivity scores; I, inattention scores; ODD, oppositional defiant disorder; SD, standard deviation.

Table 3 Correlations among 2D/4D ratios, salivary testosterone levels, patients’ characteristics, and neuropsychological functions among ADHD patients

Variables	2D/4D ratio				Salivary testosterone level
	Males		Females		Males		Females
	r	P-value	r	P-value	r	P-value	r	P-value
Age (years)	0.114	0.153	0.115	0.470	0.222	0.005**	0.040	0.801
Height (cm)	0.102	0.200	0.107	0.501	0.222	0.005**	−0.127	0.423
Weight (kg)	0.125	0.117	−0.006	0.971	0.239	0.003**	−0.062	0.696
Body mass index (kg/m^2)	0.108	0.174	−0.035	0.827	0.170	0.036*	−0.024	0.882
WISC-IV
Full Scale Intelligence Quotient	0.089	0.269	−0.009	0.957	0.049	0.541	0.196	0.213
Verbal Comprehension Index	0.078	0.328	0.072	0.651	0.021	0.798	0.092	0.563
Perceptual Reasoning Index	0.140	0.078	−0.081	0.608	0.078	0.327	0.482	0.001**
Working Memory Index	0.039	0.627	0.080	0.615	0.023	0.772	0.036	0.823
Processing Speed Index	−0.055	0.494	0.069	0.664	0.006	0.937	−0.197	0.211
Clinical measures
SNAP-IV parent form (I)	−0.009	0.909	0.228	0.147	0.104	0.193	0.219	0.163
SNAP-IV parent form (H)	−0.055	0.492	0.199	0.206	0.103	0.200	0.235	0.134
SNAP-IV parent form (O)	−0.021	0.796	0.066	0.680	0.103	0.198	−0.056	0.727
SNAP-IV teacher form (I)	0.111	0.166	−0.202	0.200	0.057	0.477	−0.060	0.705
SNAP-IV teacher form (H)	−0.029	0.719	−0.056	0.723	0.043	0.592	−0.177	0.261
SNAP-IV teacher form (O)	0.021	0.793	0.158	0.318	0.082	0.305	−0.091	0.566
Indices of CPT
Confidence Index	−0.061	0.448	−0.008	0.962	0.100	0.211	0.368	0.017*
Omission	0.029	0.719	−0.034	0.829	0.053	0.507	0.622	<0.001***
Commission	−0.041	0.609	−0.046	0.773	−0.010	0.897	−0.103	0.518
Hit reaction time	−0.031	0.701	0.076	0.632	0.004	0.957	0.089	0.574
Detectability	−0.013	0.873	−0.082	0.604	−0.048	0.547	0.153	0.334

Notes: r= Pearson’s correlation coefficient.

* P<0.05,

** P<0.01,

*** P<0.001.

Abbreviations: 2D/4D ratio, ratio of the length of the right index finger (2D) to that of the right ring finger (4D); ADHD, attention-deficit/hyperactivity disorder; CPT, Conners’ Continuous Performance Test; H, hyperactivity/impulsivity scores; I, inattention scores; O, oppositional scores; SNAP-IV, the Swanson, Nolan, and Pelham – Version IV Scale for ADHD; WISC-IV, Wechsler Intelligence Scale for Children – Fourth Edition.