Article

Abnormal circadian rhythm and cortisol excretion in autistic children: A clinical study

Geetha Arumugam, Department of Biochemistry, Bharathi Women's College (Affiliated to University of Madras), North Chennai - 600 108, Tamil Nadu, India, .
Croatian Medical Journal (Impact Factor: 1.31). 02/2013; 54(1):33-41. DOI: 10.3325/cmj.2013.54.33
Source: PubMed

ABSTRACT

Aim
To determine the circadian rhythm alteration of cortisol excretion and the level of corticosteroids in children with different grades of autism severity.

Methods
The study included 45 children with different grades of autism severity (low [LFA], medium [MFA], and high functioning autism [HFA]), 15 in each group, and 45 age/sex-matched children with typical development. The urinary levels of free cortisol (at three phases of 24-hour cycle), corticosteroids, vanilylmandelic acid, and 5-hydroxyindole acetic acid were determined.

Results
Alteration in the pattern of cortisol excretion (Phases I, II, and III) was observed in children with LFA (Phase I: 43.8 ± 4.43 vs 74.30±8.62, P = 0.000; Phase II: 21.1±2.87 vs 62±7.68, P < 0.001; Phase III: 9.9 ± 1.20 vs 40 ± 5.73, P < 0.001) and MFA (Phase I: 43.8 ± 4.43 vs 52.6±7.90, P < 0.001; Phase II: 21.1±2.87 vs 27.4±4.05, P < 0.001; Phase III: 9.9 ± 1.20 vs 19 ± 2.50, P < 0.001) compared to the control group. The corticosteroids excretion levels were higher in all the groups of children with autism than in the control group. The level of 5-hydroxyindole acetic acid was significantly higher in children with LFA (8.2±1.48 vs 6.8±0.85, P < 0.001) and MFA (8.2±1.48 vs 7.4± 0.89, P = 0.001) and not significantly higher in children with HFA than in the control group. The changes were correlated with degrees of severity of the disorder.

Conclusion
These data suggest that altered cortisol excretion pattern and high level of corticosteroids in urine may probably be a consequence of altered hypothalamic-pituitary-adrenal axis function, which may contribute to the pathogenesis and affect the severity of autism.

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