Reference intervals for 6-sulfatoxymelatonin in urine: A meta-analysis.

Despite the essential functions of melatonin in the human body, until now no norms of the amount of melatonin produced overnight have been established. Measuring the amount of the main urinary melatonin metabolite 6-sulfatoxymelatonin (aMT6s), corrected for creatinine, in the first morning void is the most simple as well as reliable method to evaluate the total amount of melatonin produced at night. We performed a meta-analysis to provide reference estimates and intervals by consolidating data from multiple studies. A total of 68 studies, representing 17,847 subjects, were retained for the analysis. No gender differences could be found in aMT6s values in this meta-review. aMT6s excretion is very high during the first 5 years of life, flattens out in adolescence with gradual decline continuing to 50-60 years, after which the decline stagnates and a limited increase occurs around about 60 years of age. This late increase may suggest the premature death of individuals with low aMT6s levels, as lower aMT6s levels are found in various disorders, such as cardiovascular diseases, cancer and neurodegenerative disorders. Our aMT6s values can be used to identify individuals with a possible melatonin deficiency.

Exogenous melatonin for sleep problems in individuals with intellectual disability: a meta-analysis.

Recent meta-analyses on melatonin has raised doubts as to whether melatonin is effective in treating sleep problems in people without intellectual disabilities. This is in contrast to results of several trials on melatonin in treating sleep problems in individuals with intellectual disabilities. To investigate the efficacy of melatonin in treating sleep problems in individuals with intellectual disabilities, we performed a meta-analysis of placebo-controlled randomized trials of melatonin in individuals with intellectual disabilities and sleep problems. Data were selected from articles published on PubMed, Medline, and Embase between January 1990 and July 2008. We examined the influence of melatonin on sleep latency, total sleep time, and number of wakes per night. Quality of trials was assessed using the Downs and Black checklist. Nine studies (including a total of 183 individuals with intellectual disabilities) showed that melatonin treatment decreased sleep latency by a mean of 34 minutes (p<0.001), increased total sleep time by a mean of 50 minutes (p<0.001), and significantly decreased the number of wakes per night (p<0.05). Melatonin decreases sleep latency and number of wakes per night, and increases total sleep time in individuals with intellectual disabilities.

Melatonin for chronic insomnia in Angelman syndrome: a randomized placebo-controlled trial.

Previous studies suggested that melatonin improves sleep in insomniac patients with Angelman syndrome. To assess the efficacy of melatonin, a randomized placebo-controlled study was conducted in 8 children with Angelman syndrome with idiopathic chronic insomnia. After a 1-week baseline period, patients received, depending on age, either melatonin 5 or 2.5 mg, or placebo, followed by 4 weeks of open treatment. Parents recorded lights off time, sleep onset time, wake-up time, and epileptic seizures in a diary. Salivary melatonin levels were measured at baseline and the last evening of the fourth treatment week. Melatonin significantly advanced sleep onset by 28 minutes, decreased sleep latency by 32 minutes, increased total sleep time by 56 minutes, reduced the number of nights with wakes from 3.1 to 1.6 nights a week, and increased endogenous salivary melatonin levels. Parents were satisfied with these results. Indications that melatonin dose in Angelman syndrome patients should be low, are discussed.

Sleep in Angelman syndrome: A review of evidence.

Sleep problems are reported to be extremely prevalent in individuals with developmental disabilities. The consensus guidelines for Angelman syndrome (AS) consider abnormal sleep-wake cycles and diminished need for sleep as associated features. We report an integrative research review and a meta-analysis of studies with sleep as the primary aim of investigation in an AS sample. 14 studies met eligibility criteria with half of them being surveys. Thirteen of the 17 conceptually formed sleep disorder item-groups showed to be significant for individuals with AS. There is evidence that arousal during sleep, somnolence and possibly short sleep duration are the primary sleep problems in individuals with AS. According to the results of this review and meta-analyses, there is clear evidence for sleep problems in individuals with AS. Individual effect sizes remain overall small, but nevertheless findings suggest disorders of arousal and sleepiness to be distinctive. In light of these findings, other sleep complaints in individuals with AS should be carefully examined. Consistent standards for research on sleep in individuals with AS are critical for new lines of investigation.

Low maternal melatonin level increases autism spectrum disorder risk in children.

BACKGROUND: It is assumed that autism spectrum disorder (ASD) is caused by a combination of de novo inherited variation and common variation as well as environmental factors. It often co-occurs with intellectual disability (ID). Almost eight hundred potential causative genetic variations have been found in ASD patients. However, not one of them is responsible for more than 1% of ASD cases. Low melatonin levels are a frequent finding in ASD patients. Melatonin levels are negatively correlated with severity of autistic impairments, it is important for normal neurodevelopment and is highly effective in protecting DNA from oxidative damage. Melatonin deficiency could be a major factor, and well a common heritable variation, that increases the susceptibility to environmental risk factors for ASD. ASD is already present at birth. As the fetus does not produce melatonin, low maternal melatonin levels may be involved. METHODS: We measured 6-sulfatoxymelatonin in urine of 60 mothers of a child with ASD and controls. RESULTS: 6-sulfatoxymelatonin levels were significantly lower in mothers with an ASD child than in controls (p = 0.012). CONCLUSIONS: Low parental melatonin levels could be one of the contributors to ASD and possibly ID etiology. Our findings need to be duplicated on a larger scale. If our hypothesis is correct, this could lead to policies to detect future parents who are at risk and to treatment strategies to ASD and intellectual disability risk.

Sleep Complaints and the 24-h Melatonin Level in Individuals with Smith-Magenis Syndrome: Assessment for Effective Intervention.

AIMS: Individuals with Smith-Magenis syndrome (SMS) are reported to have a disrupted circadian rhythm. Our aim was to examine problematic sleeping in those attending our sleep clinic for the first time. METHODS: At intake, caregivers of 50 children and nine adults with SMS were surveyed about the sleep pattern and potential melatonin administration. Sampling of salivary melatonin levels was performed. RESULTS: At intake, exogenous melatonin was used by 16 children (27.1% of sample; 56.3% male) with mean age 6.8 ± 2.8 years, whereas 34 children (57.6%; 7.5 ± 4.8 years old; 64.7% male) and nine adults (15.3%; 36.8 ± 15.3 years old; 44.4% male) were not taking melatonin at intake. Participants were reported to have problems with night waking and early awakenings regardless of melatonin administration. Overall, moderate to high levels of salivary melatonin at noon were found in individuals with SMS. In particular, children with SMS showed a disrupted melatonin pattern. Furthermore, the endogenous melatonin level, age, and gender may potentially interact, yielding the severity range of sleep disturbances reported in SMS. CONCLUSION: Treatment of sleep problems in SMS is complex, and our findings may support person-centered sleep and medication management. Future clinical trials including larger groups may shed light on such approaches.

Current role of melatonin in pediatric neurology: clinical recommendations.

BACKGROUND/PURPOSE: Melatonin, an indoleamine secreted by the pineal gland, plays a key role in regulating circadian rhythm. It has chronobiotic, antioxidant, anti-inflammatory and free radical scavenging properties. METHODS: A conference in Rome in 2014 aimed to establish consensus on the roles of melatonin in children and on treatment guidelines. RESULTS AND CONCLUSION: The best evidence for efficacy is in sleep onset insomnia and delayed sleep phase syndrome. It is most effective when administered 3-5 h before physiological dim light melatonin onset. There is no evidence that extended-release melatonin confers advantage over immediate release. Many children with developmental disorders, such as autism spectrum disorder, attention-deficit/hyperactivity disorder and intellectual disability have sleep disturbance and can benefit from melatonin treatment. Melatonin decreases sleep onset latency and increases total sleep time but does not decrease night awakenings. Decreased CYP 1A2 activity, genetically determined or from concomitant medication, can slow metabolism, with loss of variation in melatonin level and loss of effect. Decreasing the dose can remedy this. Animal work and limited human data suggest that melatonin does not exacerbate seizures and might decrease them. Melatonin has been used successfully in treating headache. Animal work has confirmed a neuroprotective effect of melatonin, suggesting a role in minimising neuronal damage from birth asphyxia; results from human studies are awaited. Melatonin can also be of value in the performance of sleep EEGs and as sedation for brainstem auditory evoked potential assessments. No serious adverse effects of melatonin in humans have been identified.

Psychometric properties of a sleep questionnaire for use in individuals with intellectual disabilities.

We examined the psychometric properties of one part of the Sleep Questionnaire developed by Simonds and Parraga (SQ-SP; 1982), a questionnaire that is frequently used to explore sleep problems and behaviors related to sleep in individuals with intellectual disability (ID). The SQ-SP was completed for 345 individuals with ID (sleep clinic n = 146; control group n = 103; published studies n = 68; psychiatric clinic n = 28). Internal consistency was good (Cronbach's α = .80) and test-retest reliability for the total SQ-SP score was also good (Spearman's rank correlation = .83, p<.01). Convergent validity was adequate (r = .79, p<.001) and concurrent validity was satisfactory (r = .52, p<.001). Exploratory factor analysis suggested a 5-factor structure (Snoring, Daytime sleepiness, Complaints related to sleep, Sleep apnea and Anxiety related to sleep). Internal consistency of the five factors ranged from modest (Cronbach's α = .57) to good (Cronbach's α = .82). Confirmatory factor analysis corroborated the 5-factor structure. The Composite Sleep Index, the total SQ-SP score and the factor scores on Daytime Sleepiness and Complaints related to sleep were able to differentiate the control group from the sleep clinic group. The SQ-SP appears to be a reliable and valid tool in assessing sleep and different types of sleep disturbance in individuals with ID.