Circadian cortisol profiles, anxiety and depressive symptomatology, and body mass index in a clinical population of obese children

Figures & data

Table I.  Characteristics of the study population (N = 128).

	Total	Females (n = 68)	Males (n = 60)	p-Value^*
Age (years, mean ± SD)	11.2 ± 2.2	10.7 ± 2.1	11.4 ± 2.1	0.036
BMI (kg/m^2, mean ± SD)	29.6 ± 5.5	29.4 ± 5.7	29.7 ± 5.2	0.700
BMI z-score (mean ± SD)	2.9 ± 1.5	3.0 ± 1.6	2.9 ± 1.5	0.800
Pubertal status, pre/mid/post (%)	46.3/42.6/11.1	40.0/41.8/18.2	52.8/43.4/3.8	0.057^†

^* Student's t-test

^† Fisher's exact test. BMI: body mass index.

Table II.  Distribution of the study population according to their emotional status, based on the CDI (depressive symptoms), STAIC1 (state anxiety), and STAIC2 (trait anxiety) questionnaires.

	High (>95th percentile)	Normal ( < 95th percentile)
CDI (n = 119)	19 (16.0%)	100 (84.0%)
STAIC1 (n = 93)	13 (14.0%)	80 (86.0%)
STAIC2 (n = 101)	11 (10.9%)	90 (89.1%)

Notes: BMI, body mass index; CDI, Children's Depression Inventory; STAIC1 and STAIC2, State and Trait Anxiety Inventory for Children, respectively.

Table III.  Characteristics of obese children with depressive symptoms (high CDI), symptoms of state anxiety (high STAIC1) and symptoms of trait anxiety (high STAIC2), presence of both anxiety and depression (co-morbidity), and low symptoms of anxiety/depression.

	Depressive symptoms(CDI >95th percentile) n = 19	State-anxiety symptoms(STAIC1>95th percentile) n = 13	Trait-anxiety symptoms(STAIC2>95th percentile) n = 11	Symptoms of anxiety and depression (co-morbidity) n = 7	No symptoms of anxiety/depression (low symptoms in all scales) n = 32
Age (years, mean ± SD)	11.3 ± 2.1	10.5 ± 2.3	11.6 ± 2.4	11.5 ± 2.6	10.6 ± 2.2
BMI z-score (mean ± SD)	3.5 ± 1.6	3.2 ± 0.9	3.9 ± 1.8	3.8 ± 2.2	2.9 ± 1.3
Gender, males/females (%)	52.6/47.4	41.7/58.3	45.5/54.5	42.9/57.1	50.0/50.0

Notes: BMI, body mass index; CDI, Children's Depression Inventory; STAIC1 and STAIC2, State and Trait Anxiety Inventory for Children, respectively.

Table IV.  Effect of state anxiety (STAIC1), trait anxiety (STAIC2), depressive symptoms (CDI), age, gender, and time on daily variation of salivary cortisol concentration as assessed by repeated measurements analysis.^*

Variable	Coefficient	t Value	Degrees of freedom	p-Value^†
Intercept	0.14	3.15	50	0.003
Time	− 0.072	− 6.88	50	< 0.001
Square of time	0.008	5.29	50	< 0.001
Cube of time	− 0.0003	− 4.51	50	< 0.001
STAIC1^‡	− 0.039	− 1.98	50	0.053
STAIC2	0.022	− 0.65	50	0.52
CDI	0.029	1.11	50	0.27
Gender^¶	0.025	1.95	50	0.057
Age^§	0.010	3.92	50	< 0.001

CDI, Children's Depression Inventory; STAIC1 and STAIC2, State and Trait Anxiety Inventory for Children, respectively.

^*Repeated measures analysis with correlated error terms using an unstructured correlation matrix

^† Wald test

^‡ Patients with STAIC1 below the 95th percentile had lower average values of salivary cortisol concentration than those with STAIC1 above the 95th percentile (average difference 0.039 μg/dl, p = 0.05)

^¶ Females had higher average values of salivary cortisol than males (average difference 0.025 μg/dl, p = 0.057)

^§ Age had a positive effect on salivary cortisol values (1-year increase in age results in an average increase of 0.01 μg/dl in salivary cortisol values).

Table V.  The effect of psychological morbidity on the variation of cortisol measurements as assessed by repeated measures analysis.^*

	Coefficient	t Value	Degrees of freedom	p-Value^†
Psychological morbidity
Low psychological symptoms vs. anxiety or depression	− 0.046	2.25	51	0.028
Anxiety and depression vs. anxiety or depression	− 0.059	2.24	51	0.029
Low psychological symptoms vs. anxiety and depression	0.012	0.68	51	0.490
Time	− 0.072	− 6.88	51	< 0.001
Square of time	0.008	5.29	51	< 0.001
Cube of time	− 0.0003	− 4.51	51	< 0.001
Gender‡	0.025	2.03	51	0.047
Age^¶	0.010	3.92	51	< 0.001

^* Repeated measures analysis with correlated error terms using an unstructured correlation matrix

^† Wald test

^‡ Females had higher average values of salivary cortisol than males (average difference 0.025 μg/dl, p = 0.047)

^¶ Age had a positive effect on salivary cortisol values (1-year increase in age results in an average increase of 0.01 μg/dl in salivary cortisol values, p < 0.001).

Figure 1.  Mean daily variation of salivary cortisol concentration, as predicted by repeated measures analysis (repeated measures analysis with correlated error terms using an unstructured correlation matrix; details are given in Tables IV and V), for girls (1a) and boys (1b) at the age of 10 years. Anxiety and depression symptoms were determined by the State and Trait Anxiety Inventory for Children (STAIC1 and STAIC2), and the CDI, respectively.