Vitamin D levels in children with attention deficit hyperactivity disorder: Association with seasonal and geographical variation, supplementation, inattention severity, and theta:beta ratio

Association of cord blood vitamin D with child neurodevelopment at 7 years of age

AIM

The role of fetal vitamin D [25-hydroxyvitamin D (25(OH)D)], one of the nuclear steroid transcription regulators, and brain development is unclear. We previously found a weak but persistent association between cord blood 25(OH)D and child language abilities at 18 months and 4 years of age, but no association with cognition or behaviour. The aim of this study was to investigate the association between cord blood 25(OH)D and a range of neurodevelopmental outcomes in these same children at 7 years of age.

METHODS

Cord blood samples from 250 Australian mother-child pairs were analysed for 25(OH)D by mass spectroscopy. Children underwent tests of cognition, language, academic abilities and executive functions with a trained assessor at 7 years of age. Caregivers completed questionnaires to rate their child's behaviour and executive functioning in the home environment. Associations between standardised 25(OH)D and outcomes were assessed using regression models, taking into account possible social and demographic confounders.

RESULTS

Standardised 25(OH)D in cord blood was not associated with any test or parent-rated scores. Nor was there any association with the risk of having a poor test or parent-rated score. Likewise, cord blood 25(OH)D categorised as <25, 25-50 and >50 nmol/L was not associated with test scores or parent-rated scores.

CONCLUSIONS

There was no evidence that cord blood vitamin D concentration or deficiency was associated with cognition, language, academic abilities, executive functioning or behaviour at 7 years of age.

Effect of 25 hydroxyvitamin D on attention deficit and hyperactivity in school-age children with ADHD

BACKGROUND

To observe the serum levels of 25 hydroxyvitamin D [25 (OH) D] in healthy school-age children and children with attention deficit hyperactivity disorder (ADHD) and to analyze the effects of serum 25 (OH) D on the symptoms of attention deficit and hyperactivity in school-age children with ADHD.

METHODS

According to the Diagnostic and Statistical Manual of Mental Disorders DSM-IV diagnostic criteria for ADHD in children, 80 healthy children aged 6 years or less than 10 years old and children diagnosed with ADHD in the Department of Rehabilitation Medicine, Department of Pediatrics and Department of Physical Examination of our hospital were randomly selected as research subjects. The serum 25 (OH) D level, attention deficit hyperactivity (Swanson, Nolan, and Pelham, version IV [SNAP-IV] parental version) score and Conners child behavior (PSQ) index were observed and compared between the 2 groups. In addition, the children with ADHD whose serum 25 (OH) D was lower than normal were treated with supplemental VitD3, and the changes in serum 25 (OH) D, SNAP-IV parental score and PSQ index of ADHD children were observed and compared.

RESULTS

Serum 25(OH)D was insufficient or deficient in 26 healthy children, but the SNAP-IV score and PSQ index were normal. Serum 25(OH)D was lower than normal in 69 patients in the ADHD group, which was negatively correlated with SNAP-IV score (r = -0.3479, P = .0034) and negatively correlated with PSQ index (r = -0.3566, P = .0026). After vitamin D3 (VitD3) supplementation in 69 children with serum 25(OH)D levels lower than the normal ADHD group, it was found that the SNAP-IV score (r = -0.4654, P = .0037) and PSQ index (r = -0.5680, P = .0002) of 34 children with ADHD were negatively correlated with the increase in serum 25(OH)D. The SNAP-IV score and PSQ index of the other 35 children with ADHD showed no correlation with the increase in serum 25 (OH) D (P > .05).

CONCLUSION SUBSECTIONS

Serum 25(OH)D levels lower than normal are more common in school-age children, and levels lower than normal are not the key pathogenic factor of ADHD in school-age children, but serum 25(OH)D levels lower than normal may be the upregulation factor of attention deficit and hyperactivity disorder expression in some school-age children with ADHD. The lower level of serum 25(OH)D may be closely related to the severity of ADHD symptoms in some children.

Co-Occurrence of Tic Disorders and Attention-Deficit/Hyperactivity Disorder-Does It Reflect a Common Neurobiological Background?

BACKGROUND

The co-existence of tic disorders and attention-deficit/hyperactivity disorder (TD + ADHD) has proven to be highly important in daily clinical practice. The factor ADHD is not only associated with further comorbidities, but also has a long-term negative psychosocial effect, while the factor TD is usually less disturbing for the major part of the patients. It remains unclear how far this is related to a different neurobiological background of the associated disorders or whether TD + ADHD reflects a common one.

OBJECTIVE

This review provides an update on the neurobiological background of TD + ADHD in order to better understand and treat this clinical problem, while clarifying whether an additive model of TD + ADHD holds true and should be used as a basis for further clinical recommendations.

METHOD

A comprehensive research of the literature was conducted and analyzed, including existing clinical guidelines for both TD and ADHD. Besides genetical and environmental risk factors, brain structure and functions, neurophysiological processes and neurotransmitter systems were reviewed.

RESULTS

Only a limited number of empirical studies on the neurobiological background of TD and ADHD have taken the peculiarity of co-existing TD + ADHD into consideration, and even less studies have used a 2 × 2 factorial design in order to disentangle the impact/effects of the factors of TD versus those of ADHD. Nevertheless, the assumption that TD + ADHD can best be seen as an additive model at all levels of investigation was strengthened, although some overlap of more general, disorder non-specific aspects seem to exist.

CONCLUSION

Beyond stress-related transdiagnostic aspects, separate specific disturbances in certain neuronal circuits may lead to disorder-related symptoms inducing TD + ADHD in an additive way. Hence, within a classificatory categorical framework, the dimensional aspects of multilevel diagnostic-profiling seem to be a helpful precondition for personalized decisions on counselling and disorder-specific treatment in TD + ADHD.

Vitamin D and the Central Nervous System: Causative and Preventative Mechanisms in Brain Disorders

Twenty of the last one hundred years of vitamin D research have involved investigations of the brain as a target organ for this hormone. Our group was one of the first to investigate brain outcomes resulting from primarily restricting dietary vitamin D during brain development. With the advent of new molecular and neurochemical techniques in neuroscience, there has been increasing interest in the potential neuroprotective actions of vitamin D in response to a variety of adverse exposures and how this hormone could affect brain development and function. Rather than provide an exhaustive summary of this data and a listing of neurological or psychiatric conditions that vitamin D deficiency has been associated with, here, we provide an update on the actions of this vitamin in the brain and cellular processes vitamin D may be targeting in psychiatry and neurology.