Trends in Use of Melatonin Supplements Among US Adults, 1999-2018

Use of melatonin supplements and risk of type 2 diabetes and cardiovascular diseases in the USA: insights from three prospective cohort studies

BACKGROUND

Use of melatonin supplements has been increasing substantially in both children and adults in the USA; however, their long-term cardiometabolic effects remain unclear. We aimed to assess the associations between regular use of melatonin supplements and the risk of developing type 2 diabetes or cardiovascular disease in adults.

METHODS

In this study, we included individuals from three US cohorts: the Nurses' Health Study (women only), the Health Professionals Follow-up Study (men only), and the Nurses' Health Study II (women only). Women aged 25-55 years and men aged 45-75 years at baseline, who had no diagnosis of cancer at baseline, and who responded to the question about melatonin supplement use (yes or no) were included. We excluded baseline prevalent cardiovascular disease and baseline prevalent type 2 diabetes for the main analyses. The main outcomes were cardiovascular disease and type 2 diabetes incidence. In secondary analyses, we stratified by duration of rotating night shift work in the Nurses' Health Study and Nurses' Health Study II to examine whether the associations with melatonin supplement use differed by rotating night shift work.

FINDINGS

For the cardiovascular disease analysis, we included 67 202 women from the Nurses' Health Study (follow-up 1998-2019, mean age at baseline: 63·6 years [SD 7·1]), 26 629 men from the Health Professionals Follow-up Study (1998-2020, 62·9 years [8·8], and 65 241 women from the Nurses' Health Study II (2003-19, 48·2 years [4·7]). Follow-up for incident type 2 diabetes was from 1998 to June 30, 2021, for the Nurses' Health Study; 2003 to Jan 31, 2023, for the Nurses' Health Study II; and from 1998 to Jan 31, 2020, for the Health Professionals' Follow-up Study. Melatonin supplement use in the study cohorts doubled over recent decades from less than 2% in 1998-2007 to 4% or higher in 2014-15 (4·0% in men and 5·3% in women). We documented 16 917 incident cardiovascular disease events during 2 609 068 person-years of follow-up and 12 730 incident cases of type 2 diabetes during 2 701 830 person-years of follow-up. In a pooled analysis of the three cohorts, comparing users with non-users of melatonin supplements, the pooled multivariable-adjusted hazard ratios were 0·94 (95% CI 0·83-1·06, p=0·32) for cardiovascular disease and 0·98 (0·86-1·12, p=0·80) for type 2 diabetes. In secondary analyses, melatonin supplement use appeared to attenuate the positive association between long-term shift work (>5 years) and risk of cardiovascular disease (pinteraction=0·013) among the female nurses.

INTERPRETATION

With up to 23 years of follow-up of three large prospective cohorts of middle-aged and older men and women, self-reported melatonin supplement use was not associated with risk of type 2 diabetes or cardiovascular disease. Further research is warranted to assess if melatonin supplement use could mitigate the potential risks of type 2 diabetes and cardiovascular disease associated with rotating night shift work.

FUNDING

US National Institutes of Health.

Psychiatric comorbidities and prescribing tendencies of sleep medications and related medications in young people with insomnia: a United States commercial claims-based analysis

STUDY OBJECTIVES

To characterize children and youth newly diagnosed with insomnia and to describe their use of sleep and other related prescription medications.

METHODS

Within a commercial claims database (January 1, 2016-December 31, 2021), we identified children and youth (2-24 years) with a newly recorded insomnia diagnosis (G47.0x; F51.0x) and examined psychiatric diagnoses in the prior 6 months. We evaluated sleep and related prescription medications dispensed in the week after new insomnia diagnoses (i.e. trazodone, other antidepressants, hydroxyzine, alpha-agonists, benzodiazepines, non-benzodiazepine hypnotics "z-drugs," antipsychotics, and others). Analyses were stratified by age and psychiatric comorbidities.

RESULTS

Among 68 698 children and 108 118 older youth (18-24 years) with a new insomnia diagnosis, three-quarters had a diagnosed comorbid psychiatric condition; anxiety disorders, depression, and ADHD were the most common. Among those without comorbid psychiatric diagnoses, 20.2% of children and 37.4% of older youth had a sleep or related medication dispensed in the following week. In children without a comorbid psychiatric diagnosis, alpha-agonists, hydroxyzine, and trazodone were the most common medications; in older youth, trazodone was the most common medication followed by hydroxyzine, z-drugs, and SSRIs. Sleep and related prescription medications were more commonly dispensed to those with psychiatric comorbidities. From 2017 to 2021, there was an increase in hydroxyzine prescriptions following a new insomnia diagnosis and decline in z-drug and benzodiazepine prescriptions.

CONCLUSIONS

Our findings from a nationwide sample of young people with insomnia highlight the high prevalence of psychiatric comorbidities and variety of sleep and related medications they receive. Characterizing prescribing tendencies informs guideline development and future research.

Assessment of melatonin's therapeutic effectiveness against hepatic steatosis induced by a high-carbohydrate high-fat diet in rats

Several studies have demonstrated the protective effects of melatonin against metabolic diseases, such as liver steatosis. However, its therapeutic effects have received less scrutiny. The present study aimed to explore melatonin's therapeutic effectiveness in treating non-alcoholic fatty liver disease (NAFLD) induced by a high-carbohydrate high-fat (HCHF) diet in rats. The NAFLD was developed in male Wistar rats using an HCHF diet for 8 weeks. Afterward, they were given melatonin orally for four weeks at doses of 5 mg/kg, 10 mg/kg, and 30 mg/kg, along with the HCHF diet. In addition, six age-matched healthy rats received the highest dose of melatonin (30 mg/kg) for the same duration. Rats on the HCHF diet exhibited obesity, dyslipidemia, hyperglycemia, glucose intolerance, insulin resistance, inflammation, oxidative stress, and liver injury (steatosis). Melatonin treatment at 10 mg/kg and 30 mg/kg reduced body weight, adiposity index, oxidative damage, and inflammation but did not affect impaired glucose metabolism induced by the HCHF diet. Meanwhile, the highest dose of melatonin (30 mg/kg) reduced the liver steatosis index in HCHF rats but caused mild liver damage in healthy rats. In conclusion, using melatonin demonstrated positive outcomes in treating NAFLD induced by the HCHF diet in rats, with no noteworthy effects observed in healthy rats. A moderate dosage of 10 mg/kg of melatonin proved to be a safer and more efficient method for reducing HCHF diet-induced NAFLD in rats. Higher melatonin doses should be cautiously administered due to potential disruptions in lipid metabolism and the risk of liver complications.

Protective Effects of Melatonin against Carcinogen-Induced Oxidative Damage in the Thyroid

Melatonin, primarily synthesized in the pineal gland, plays a crucial role in regulating circadian rhythms and possesses significant antioxidative properties. By neutralizing free radicals and reducing oxidative stress, melatonin emerges as a promising agent for the prevention and therapy of many different disorders, including cancer. This paper reviews the relationship between the thyroid gland and melatonin, presenting experimental evidence on the protective effects of this indoleamine against oxidative damage to macromolecules in thyroid tissue caused by documented carcinogens (as classified by the International Agency for Research on Cancer, IARC) or caused by potential carcinogens. Furthermore, the possible influence on cancer therapy in humans and the overall well-being of cancer patients are discussed. The article highlights melatonin's essential role in maintaining thyroid health and its contribution to management strategies in patients with thyroid cancer and other thyroid diseases.

Melatonin and melatonin receptor agonists in the treatment of nocturia: A systematic review

AIM

Causes of nocturia may extend beyond primary bladder pathology and it has been commonly associated as a side effect of sleep disorders. This has led to the study of melatonin and melatonin receptor agonists as a primary treatment for nocturia hypothesized to be secondary to sleep disorders. We aim to systematically review the efficacy and reported safety of melatonin and melatonin receptor agonists in the treatment of nocturia.

METHODS

A search strategy of EMBASE and Pubmed/Medline databases was utilized to identify eligible studies. Two thousand and twenty-eight unique references were identified in concordance with the Preferred Reporting Items of Systematic Reviews and Meta-Analyses guidelines for systematic reviews, of which nine papers met the inclusion criteria. The Cochrane Collaboration risk of bias criteria in the open label and nonplacebo studies was used to assess bias.

RESULTS

The nine studies identified included 3 randomized double-blinded placebo-controlled trials, 2 randomized non-placebo trial, and 4 prospective open-label trials. Three utilized the melatonin-receptor agonist ramelteon (8 mg) and six utilized melatonin (four 2 mg extended release, two 2 mg normal release). Nocturia improved in 8 studies varying from moderate to low efficacy related to reduction in nocturia episodes. Five studies evaluated sleep parameters finding improvement in both nocturia and sleep quality. Male subjects represented 76.8% of 371 total subjects in prospective and randomized trials. Ramelteon and melatonin were both reported as well tolerated during nocturia treatment. A meta-analysis was not able to be performed due to the heterogeneity of bladder diagnoses.

CONCLUSIONS

At this time, there is insufficient evidence to routinely recommend melatonin as an effective treatment for nocturia given the limitations of current clinical studies. Randomized placebo-controlled trials and prospective open label studies in non-neurogenic populations report a trend towards nocturia improvement with good tolerability and rare side effects. Therefore, further larger scale randomized trials with focused urologic diagnoses in well-characterized patient populations are warranted.

Meditation Experience is Associated with Increased Structural Integrity of the Pineal Gland and greater total Grey Matter maintenance

Growing evidence demonstrates that meditation practice supports cognitive functions including attention and interoceptive processing, and is associated with structural changes across cortical networks including prefrontal regions, and the insula. However, the extent of subcortical morphometric changes linked to meditation practice is less appreciated. A noteworthy candidate is the Pineal Gland, a key producer of melatonin, which regulates circadian rhythms that augment sleep-wake patterns, and may also provide neuroprotective benefits to offset cognitive decline. Increased melatonin levels as well as increased fMRI BOLD signal in the Pineal Gland has been observed in mediators vs. controls. However, it is not known if long-term meditators exhibit structural change in the Pineal Gland linked to lifetime duration of practice. In the current study we performed Voxel-based morphometry (VBM) analysis to investigate: 1) whether long-term meditators (LTMs) (n=14) exhibited greater Pineal Gland integrity compared to a control group (n=969), 2) a potential association between the estimated lifetime hours of meditation (ELHOM) and Pineal Gland integrity, and 3) whether LTMs show greater Grey Matter (GM) maintenance (BrainPAD) that is associated with Pineal Gland integrity. The results revealed greater Pineal Gland integrity and lower BrainPAD scores (younger brain age) in LTMs compared to controls. Exploratory analysis revealed a positive association between ELHOM and greater signal intensity in the Pineal Gland but not with GM maintenance as measured by BrainPAD score. However, greater Pineal integrity and lower BrainPAD scores were correlated in LTMs. The potential mechanisms by which meditation influences Pineal Gland function, hormonal metabolism, and GM maintenance are discussed - in particular melatonin's roles in sleep, immune response, inflammation modulation, and stem cell and neural regeneration.

Metabolic management of accidental intoxication

PURPOSE OF REVIEW

Unintentional intoxication comprises a major chunk of all intoxications. Most patients are in the pediatric age group with another set of patients being the elderly. Substances found to cause accidental intoxication vary from country to country and even within different regions of a country. Frequent reviews of current literature are needed to be abreast of trends.

RECENT FINDINGS

Prescription drugs and household chemicals are major culprits when it comes to accidental intoxication. Acetaminophen, digoxin and metformin are some of the prominent prescription drugs frequently associated with unintentional intoxications. Increasingly alcohol based hand sanitizers are becoming an important etiology of these events, following their increased usage during the COVID-19 pandemic. Pattern recognition to identify class of intoxicant and supportive care including prevention of further absorption and increased excretion are cornerstones of therapy. Antidote when available should be used promptly.

SUMMARY

Knowledge about current epidemiology of accidental intoxications, toxidrome pattern recognition and appropriate antidote usage beside adequate and timely supportive care help in successful management of the unfortunate victim of accidental intoxication.

Complementary health approaches and dietary supplement use trends among U.S. college students: A brief report

OBJECTIVE

Examine differences over time in use of complementary health approaches (CHA) and dietary supplements among college students.

PARTICIPANTS

Two samples of undergraduate students (Sample 1, N = 370; Sample 2, N = 482) from a midsized Midwestern university.

METHOD

Using stratified random sampling, at two time points (spring 2008, spring 2019), students were surveyed. Frequency of CHA and supplement use in the past year were assessed and compared across the two time periods.

RESULTS

Of the CHAs compared, 53% had changed in frequency of use with only the practice of yoga significantly increasing. As for supplements, 78% changed in their frequency of use with the rate of melatonin being the only significant increase.

CONCLUSIONS

Although the reported use of many CHAs and supplements appeared to change in the time period between assessments, findings suggest that students still report using several CHA practices and, to a lesser extent, supplements.

Melatonin as a chronobiotic/cytoprotective agent in bone. Doses involved

Because the chronobiotic and cytoprotective molecule melatonin diminishes with age, its involvement in postmenopausal and senescence pathology has been considered since long. One relevant melatonin target site in aging individuals is bone where melatonin chronobiotic effects mediated by MT1 and MT2 receptors are demonstrable. Precursors of bone cells located in bone marrow are exposed to high quantities of melatonin and the possibility arises that melatonin acts a cytoprotective compound via an autacoid effect. Proteins that are incorporated into the bone matrix, like procollagen type I c-peptide, augment after melatonin exposure. Melatonin augments osteoprotegerin, an osteoblastic protein that inhibits the differentiation of osteoclasts. Osteoclasts are target cells for melatonin as they degrade bone partly by generating free radicals. Osteoclast activity and bone resorption are impaired via the free radical scavenger properties of melatonin. The administration of melatonin in chronobiotic doses (less than 10 mg daily) is commonly used in clinical studies on melatonin effect on bone. However, human equivalent doses allometrically derived from animal studies are in the 1-1.5 mg/kg/day range for a 75 kg human adult, a dose rarely used clinically. In view of the absence of toxicity of melatonin in phase 1 pharmacological studies with doses up to 100 mg in normal volunteers, further investigation is needed to determine whether high melatonin doses have higher therapeutic efficacy in preventing bone loss.

Functional and pharmacological analyses of visual habituation learning in larval zebrafish

Habituation allows animals to learn to ignore persistent but inconsequential stimuli. Despite being the most basic form of learning, a consensus model on the underlying mechanisms has yet to emerge. To probe relevant mechanisms, we took advantage of a visual habituation paradigm in larval zebrafish, where larvae reduce their reactions to abrupt global dimming (a dark flash). We used Ca2+ imaging during repeated dark flashes and identified 12 functional classes of neurons that differ based on their rate of adaptation, stimulus response shape, and anatomical location. While most classes of neurons depressed their responses to repeated stimuli, we identified populations that did not adapt or that potentiated their response. These neurons were distributed across brain areas, consistent with a distributed learning process. Using a small-molecule screening approach, we confirmed that habituation manifests from multiple distinct molecular mechanisms, and we have implicated molecular pathways in habituation, including melatonin, oestrogen, and GABA signalling. However, by combining anatomical analyses and pharmacological manipulations with Ca2+ imaging, we failed to identify a simple relationship between pharmacology, altered activity patterns, and habituation behaviour. Collectively, our work indicates that habituation occurs via a complex and distributed plasticity processes that cannot be captured by a simple model. Therefore, untangling the mechanisms of habituation will likely require dedicated approaches aimed at sub-component mechanisms underlying this multidimensional learning process.

Community Pharmacists' Knowledge, Attitudes and the Perceived Safety and Effectiveness of Melatonin Supplements: A Cross-Sectional Survey

Melatonin, which is classified as a dietary supplement by the Saudi Food and Drug Authority, is used to manage sleep disorders. In this study, community pharmacists' knowledge and attitudes about dispensing melatonin supplements and the perceived safety and effectiveness of melatonin were assessed. A cross-sectional survey of community pharmacists in Jeddah, Saudi Arabia was conducted from March-June 2023. Community pharmacists' knowledge and attitudes towards prescribing and dispensing melatonin supplements, the methods of dispensing melatonin supplements (prescription, over the counter, self-administered), indications, ages of users, dosage forms, and adverse drug reactions related to melatonin use among consumers were surveyed using a questionnaire. Potential participants were approached face to face, a questionnaire was administered to those agreeing to participate in the study, and responses were recorded electronically. The response rate of the 300 community pharmacists who participated in this study was 83.5%. The mean age of participants was 33.6 years, and 89.3% (n = 268) of community pharmacists reported dispensing melatonin supplements. Self-medication and over the counter (n = 213; 71.2%) were the most common dispensing and prescribing patterns (p = 0.001). Awareness rates about melatonin supplement pharmacokinetics and pharmacodynamics among community pharmacists were 38% and 37%, respectively. Despite its popularity, community pharmacists reported relatively low rates of awareness of melatonin supplement pharmacokinetics and pharmacodynamics. Further attention to this issue is needed.

Dietary supplement and complementary and alternative medicine use among older adults in Australia and the United States

BACKGROUND

Dietary supplement and complementary and alternative medication (CAM) use can contribute to drug interactions, polypharmacy, nonadherence with prescription medications, and healthcare expenses, whereas evidence supporting benefits of using these products is sparse. There is a lack of current published literature describing the patterns or predictors of their use in community-dwelling older adults.

MATERIALS AND METHODS

We performed a cross-sectional analysis of community-dwelling adults from Australia and the US, aged 70 years and older (65 years for US minorities), enrolled in the ASPirin in Reducing Events in the Elderly (ASPREE) study. At study enrollment, eligible participants were required to be without concurrent 5-year life-limiting illness and free of documented evidence of cardiovascular disease, dementia, or significant physical disability. During the final study visit, a questionnaire was administered to collect information about supplement/CAM use. Data from 15,729 participants who completed this questionnaire between January 2017 and January 2018 were analyzed. Descriptive statistics were used to report the prevalence and types of products used. Factors associated with use were determined using multivariate regression.

RESULTS

Mean age of respondents was 79.6 years; 56.4% were female, 88.8% were from Australia, 56.5% reported 12 years of education or less, and 98.7% were living at home. Two-thirds (66.2%) of participants reported use of one or more supplement/CAM in the previous month. Products most commonly used included vitamin D (33.8% of participants), fish oil (22.7%), calcium (20.6%), glucosamine (14.8%), and multivitamin (12.9%). Female sex, US residency, higher education, polypharmacy (prescription medications), and frailty (in women) were significantly associated with higher use of supplements/CAMs.

CONCLUSIONS

Dietary supplement and CAM use is common among community-dwelling older adults in the United States and Australia. Given the high prevalence of use, collaboration between healthcare providers and older adult patients is important to insure safe and optimal use of these products.

Age-Related Effects of Exogenous Melatonin on Anxiety-like Behavior in C57/B6J Mice

The synthesis of melatonin (MLT) physiologically decreases during aging. Treatment with MLT has shown anxiolytic, hypnotic, and analgesic effects, but little is known about possible age-dependent differences in its efficacy. Therefore, we studied the effects of MLT (20 mg/kg, intraperitoneal) on anxiety-like behavior (open field (OFT), elevated plus maze (EPMT), three-chamber sociability, and marble-burying (MBT) tests), and the medial prefrontal cortex (mPFC)-dorsal hippocampus (dHippo) circuit in adolescent (35-40 days old) and adult (three-five months old) C57BL/6 male mice. MLT did not show any effect in adolescents in the OFT and EPMT. In adults, compared to vehicles, it decreased locomotor activity and time spent in the center of the arena in the OFT and time spent in the open arms in the EPMT. In the MBT, no MLT effects were observed in both age groups. In the three-chamber sociability test, MLT decreased sociability and social novelty in adults, while it increased sociability in adolescents. Using local field potential recordings, we found higher mPFC-dHippo synchronization in the delta and low-theta frequency ranges in adults but not in adolescents after MLT treatment. Here, we show age-dependent differences in the effects of MLT in anxiety paradigms and in the modulation of the mPFC-dHippo circuit, indicating that when investigating the pharmacology of the MLT system, age can significantly impact the study outcomes.

Trends in Emergency Department Visits for Unsupervised Pediatric Medication Exposures

INTRODUCTION

Emergency department visits and hospitalizations for unsupervised medication exposures among young children increased in the early 2000s. Prevention efforts were initiated in response.

METHODS

Nationally representative data from the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project collected from 2009 to 2020 were analyzed in 2022 to assess overall and medication-specific trends in emergency department visits for unsupervised exposures among children aged ≤5 years.

RESULTS

From 2009 to 2020, there were an estimated 677,968 (95% CI=550,089, 805,846) emergency department visits for unsupervised medication exposures among children aged ≤5 years in the U.S. Most visits involved children aged 1-2 years (2009-2012 [70.3%], 2017-2020 [67.4%]), and nearly one half involved prescription solid medications (2009-2012 [49.4%], 2017-2020 [48.1%]). The largest declines in estimated numbers of annual visits from 2009-2012 to 2017-2020 were for exposures involving prescription solid benzodiazepines (-2,636 visits, -72.0%) and opioids (-2,596 visits, -53.6%) and over-the-counter liquid cough and cold medications (-1,954 visits, -71.6%) and acetaminophen (-1,418 visits, -53.4%). The estimated number of annual visits increased for exposures involving over-the-counter solid herbal/alternative remedies (+1,028 visits, +65.6%), with the largest increase for melatonin exposures (+1,440 visits, +421.1%). Overall, the estimated number of visits for unsupervised medication exposures decreased from 66,416 in 2009 to 36,564 in 2020 (annual percentage change= -6.0%). Emergent hospitalizations for unsupervised exposures also declined (annual percentage change= -4.5%).

CONCLUSIONS

Declines in estimated emergency department visits and hospitalizations for unsupervised medication exposures from 2009 to 2020 coincided with renewed prevention efforts. Targeted approaches may be needed to achieve continued declines in unsupervised medication exposures among young children.

Melatonin as a Chronobiotic/Cytoprotective Agent in REM Sleep Behavior Disorder

Dream-enactment behavior that emerges during episodes of rapid eye movement (REM) sleep without muscle atonia is a parasomnia known as REM sleep behavior disorder (RBD). RBD constitutes a prodromal marker of α-synucleinopathies and serves as one of the best biomarkers available to predict diseases such as Parkinson disease, multiple system atrophy and dementia with Lewy bodies. Most patients showing RBD will convert to an α-synucleinopathy about 10 years after diagnosis. The diagnostic advantage of RBD relies on the prolonged prodromal time, its predictive power and the absence of disease-related treatments that could act as confounders. Therefore, patients with RBD are candidates for neuroprotection trials that delay or prevent conversion to a pathology with abnormal α-synuclein metabolism. The administration of melatonin in doses exhibiting a chronobiotic/hypnotic effect (less than 10 mg daily) is commonly used as a first line treatment (together with clonazepam) of RBD. At a higher dose, melatonin may also be an effective cytoprotector to halt α-synucleinopathy progression. However, allometric conversion doses derived from animal studies (in the 100 mg/day range) are rarely employed clinically regardless of the demonstrated absence of toxicity of melatonin in phase 1 pharmacological studies with doses up to 100 mg in normal volunteers. This review discusses the application of melatonin in RBD: (a) as a symptomatic treatment in RBD; (b) as a possible disease-modifying treatment in α-synucleinopathies. To what degree melatonin has therapeutic efficacy in the prevention of α-synucleinopathies awaits further investigation, in particular multicenter double-blind trials.

Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis

Previous studies revealed a latitudinal gradient of multiple sclerosis (MS) prevalence, increasing by moving from the equator to the poles. The duration and quality of an individual's exposure to sunlight vary with latitude. Skin exposure to sunlight activates vitamin D synthesis, while light absence, as perceived by the eyes, activates melatonin synthesis in the pineal gland. Vitamin D or melatonin deficiency/insufficiency or overdose can occur at any latitude due to specific lifestyles and diets. Moving away from the equator, especially beyond 37°, decreases vitamin D while raising melatonin. Furthermore, melatonin synthesis increases in cold habitats like northern countries. Since melatonin's beneficial role was shown in MS, it is expected that northern countries whose individuals have higher endogenous melatonin should show a lower MS prevalence; however, these are ranked with the highest scores. In addition, countries like the United States and Canada have uncontrolled over-the-counter usage. In high latitudes, vitamin D deficiency and a higher MS prevalence persist even though vitamin D is typically compensated for by supplementation and not sunlight. Recently, we found that prolonged darkness increased MS melatonin levels, mimicking the long-term increase in northern countries. This caused a reduction in cortisol and increased infiltration, inflammation, and demyelination, which were all rescued by constant light therapy. In this review, we explain melatonin and vitamin D's possible roles in MS prevalence. The possible causes in northern countries are then discussed. Finally, we suggest strategies to treat MS by manipulating vitamin D and melatonin, preferably with sunlight or darkness, not supplements.

Melatonin’s actions are not limited to sleep

Melatonin is widely available as a supplement, usually for sleep disorders. The consumption of melatonin supplements has increased considerably in recent years. An overlooked aspect of melatonin’s administration is the resulting increase in prolactin secretion, via its action on hypothalamic dopaminergic neurons. We believe that since the effect of melatonin on prolactin is tangible, the laboratory finding of hyperprolactinemia could be encountered more often, given the increase in melatonin’s use. This is an issue that merits further study.

Sleep Disturbance in Tourette's Disorder: Potential Underlying Mechanisms

Purpose of review

Sleep disturbance is common in TD. However, our understanding of the pathophysiological mechanisms involved is preliminary. This review summarizes findings from neuroimaging, genetic, and animal studies to elucidate potential underlying mechanisms of sleep disruption in TD.

Recent findings

Preliminary neuroimaging research indicates increased activity in the premotor cortex, and decreased activity in the prefrontal cortex is associated with NREM sleep in TD. Striatal dopamine exhibits a circadian rhythm; and is influenced by the suprachiasmatic nucleus via multiple molecular mechanisms. Conversely, dopamine receptors regulate circadian function and striatal expression of circadian genes. The association of TD with restless legs syndrome and periodic limb movements indicates shared pathophysiology, including iron deficiency, and variants in the BTDB9 gene. A mutations in the L-Histidine Decarboxylase gene in TD, suggests the involvement of the histaminergic system, implicated in arousal, in TD.

Summary

These biological markers have implications for application of novel, targeted interventions, including noninvasive neuromodulation, iron supplementation, histamine receptor antagonists, and circadian-based therapies for tic symptoms and/or sleep and circadian rhythms in TD.

Circadian Rhythms Disrupted by Light at Night and Mistimed Food Intake Alter Hormonal Rhythms and Metabolism

Availability of artificial light and light-emitting devices have altered human temporal life, allowing 24-hour healthcare, commerce and production, and expanding social life around the clock. However, physiology and behavior that evolved in the context of 24 h solar days are frequently perturbed by exposure to artificial light at night. This is particularly salient in the context of circadian rhythms, the result of endogenous biological clocks with a rhythm of ~24 h. Circadian rhythms govern the temporal features of physiology and behavior, and are set to precisely 24 h primarily by exposure to light during the solar day, though other factors, such as the timing of meals, can also affect circadian rhythms. Circadian rhythms are significantly affected by night shift work because of exposure to nocturnal light, electronic devices, and shifts in the timing of meals. Night shift workers are at increased risk for metabolic disorder, as well as several types of cancer. Others who are exposed to artificial light at night or late mealtimes also show disrupted circadian rhythms and increased metabolic and cardiac disorders. It is imperative to understand how disrupted circadian rhythms alter metabolic function to develop strategies to mitigate their negative effects. In this review, we provide an introduction to circadian rhythms, physiological regulation of homeostasis by the suprachiasmatic nucleus (SCN), and SCN-mediated hormones that display circadian rhythms, including melatonin and glucocorticoids. Next, we discuss circadian-gated physiological processes including sleep and food intake, followed by types of disrupted circadian rhythms and how modern lighting disrupts molecular clock rhythms. Lastly, we identify how disruptions to hormones and metabolism can increase susceptibility to metabolic syndrome and risk for cardiovascular diseases, and discuss various strategies to mitigate the harmful consequences associated with disrupted circadian rhythms on human health.

Mediterranean Diet and Melatonin: A Systematic Review

The Mediterranean diet (MD) has beneficial effects on human health, which is evidenced by the observation of lower incidence rates of chronic diseases in Mediterranean countries. The MD dietary pattern is rich in antioxidants, such as melatonin, which is a hormone produced mainly by the pineal gland and controls several circadian rhythms. Additionally, melatonin is found in foods, such as fruit and vegetables. The purpose of this systematic review was to assess the melatonin content in Mediterranean foods and to evaluate the influence of the MD on melatonin levels in both humans and model organisms. A comprehensive search was conducted in four databases (PubMed, Scopus, Cochrane Library and Web of Science) and data were extracted. A total of 31 records were chosen. MD-related foods, such as tomatoes, olive oil, red wine, beer, nuts, and vegetables, showed high melatonin contents. The consumption of specific MD foods increases melatonin levels and improves the antioxidant status in plasma.

Current Insights into the Risks of Using Melatonin as a Treatment for Sleep Disorders in Older Adults

Exogenous melatonin is commonly used for sleep disorders in older adults, and its use is increasing over time. It appears to have modest efficacy in treating insomnia and circadian rhythm sleep-wake disorders. Melatonin is commonly perceived to be a safe alternative to other hypnotics and is available without prescription in some jurisdictions. New evidence suggests that endogenous melatonin has pleomorphic effects on multiple organ systems, many of which are poorly understood. This narrative review summarizes the current evidence regarding the safety of melatonin in older adults (defined by age over 65 years). Melatonin appears to have a favorable safety profile in this population, however there is a dearth of evidence regarding the safety of prolonged use. There are several factors which increase the risk of adverse effects of melatonin in older adults, and these should be taken into consideration when prescribing to this population.

Safety issues regarding melatonin use in child and adolescent patients with sleep problems

Several studies have reported that melatonin may be effective in treating sleep problems in children and adolescents. However, evidence regarding the safety of melatonin use in children and adolescents in their growth and developmental stages is warranted. Therefore, we aimed to summarize the literature on the safety of melatonin use in children and adolescents with insomnia and sleep disturbances. According to existing evidence, there are no serious adverse effects of long-term melatonin use in children and adolescents. The common adverse effects reported in long-term studies are fatigue, somnolence, and mood swings. In addition, there is no evidence that long-term use of melatonin inhibits the natural secretion of melatonin. It is necessary to monitor potential drug interactions with medications such as inhibitors and enhancers of cytochrome P450 1A2 (CYP1A2). Furthermore, low CYP1A2 expression in young children requires proper dose adjustment. Although sufficient experience of melatonin use in children and adolescents has yet to be attained, accumulating evidence suggests that the use of melatonin in children and adolescents with sleep problems might be effective and tolerable. Considering the abuse or overdose risk of hypnotics or benzodiazepines, melatonin supplements may be a good therapeutic alternative. Future studies on the long-term safety of melatonin for physiological and mental function in children and adolescents are required to establish certainty about melatonin use in children and adolescents.

How Would You Manage This Patient With Chronic Insomnia? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Insomnia, which is characterized by persistent sleep difficulties in association with daytime dysfunction, is a common concern in clinical practice. Chronic insomnia disorder is defined as symptoms that occur at least 3 times per week and persist for at least 3 months. The American Academy of Sleep Medicine (AASM) published recent guidelines on behavioral and psychological treatment as well as pharmacologic therapy for chronic insomnia disorder. Regarding behavioral and psychological approaches, the only intervention strongly recommended was multicomponent cognitive behavioral therapy for insomnia. Regarding pharmacologic treatment, the AASM, based on weak evidence, suggested a limited number of medications that might be useful and others that probably are not. Here, 2 clinicians with expertise in sleep disorders-one a clinical psychologist and the other a physician-debate the management of a patient with chronic insomnia who has been treated with medications. They discuss the role of behavioral and psychological interventions and pharmacologic therapy for chronic insomnia and how the primary care practitioner should approach such a patient.

Role of Psychologists in Pediatric Sleep Medicine

Sleep disorders commonly afflict infants, children, and adolescents and have a significant adverse impact on them and their families, sometimes to a severe degree. They can cause immediate stress and suffering and long-term loss of opportunities and potential. Many of these disorders can be well managed by the psychologist and often one is required, either as the sole provider or as an integral part of a team. Sleep disorders have a bidirectional interplay with mental health disorders. The patient may therefore present initially to the psychologist, primary care provider, or the sleep medicine specialist.

Is Melatonin the “Next Vitamin D”?: A Review of Emerging Science, Clinical Uses, Safety, and Dietary Supplements

Melatonin has become a popular dietary supplement, most known as a chronobiotic, and for establishing healthy sleep. Research over the last decade into cancer, Alzheimer’s disease, multiple sclerosis, fertility, PCOS, and many other conditions, combined with the COVID-19 pandemic, has led to greater awareness of melatonin because of its ability to act as a potent antioxidant, immune-active agent, and mitochondrial regulator. There are distinct similarities between melatonin and vitamin D in the depth and breadth of their impact on health. Both act as hormones, affect multiple systems through their immune-modulating, anti-inflammatory functions, are found in the skin, and are responsive to sunlight and darkness. In fact, there may be similarities between the widespread concern about vitamin D deficiency as a “sunlight deficiency” and reduced melatonin secretion as a result of “darkness deficiency” from overexposure to artificial blue light. The trend toward greater use of melatonin supplements has resulted in concern about its safety, especially higher doses, long-term use, and application in certain populations (e.g., children). This review aims to evaluate the recent data on melatonin’s mechanisms, its clinical uses beyond sleep, safety concerns, and a thorough summary of therapeutic considerations concerning dietary supplementation, including the different formats available (animal, synthetic, and phytomelatonin), dosing, timing, contraindications, and nutrient combinations.

Impact of Low-Dose Melatonin Supplementation on Testosterone Levels in U.S. Adult Males

OBJECTIVE

Amidst the rapid rise in melatonin supplementation, decreased testosterone levels amongst males in recent decades, and the unclear association between melatonin and the hypogonadal-pituitary-gland (HPG) axis, this study aimed to further examine the association of melatonin use and impact on testosterone levels among men in a nationally representative sample.

METHODS

U.S. men over the age of 18 surveyed from 2011-2016 via the National Health and Nutrition Examination Survey (NHANES) without missing demographic or pertinent health information were included in the analysis. A total testosterone (TT) level of less than 300 ng/dL was considered low. An average daily dose (ADD) was calculated to quantify participants' exposure to melatonin supplementation in the past 30 days.

RESULTS

Analysis included 7,656 participants after selection criteria. Median age of participants was 47 [31-63] years old; median TT level was 389.9 [289 - 513.9] ng/dL. Melatonin intake was reported in 51 (0.7%) individuals with an ADD of 1 [0.4 - 3] mg/day. We found no association between melatonin intake in the past 30 days and low TT levels (OR = 0.958, 95% CI: 0.496 -1.850; p=0.898). As expected, increasing BMI (OR = 1.133, 95% CI: 1.122 - 1.144; p < 0.001) and older age (OR = 1.019, 95% CI: 1.016 - 1.022; p < 0.001) were associated with low TT levels.

CONCLUSION

Predominantly low-dose melatonin supplementation was not associated with low TT levels. Future studies are needed to better quantify the relationship between melatonin intake and low TT levels, especially in the setting of supratherapeutic doses and prolonged periods of exposure.

Keep Your Mask On: The Benefits of Masking for Behavior and the Contributions of Aging and Disease on Dysfunctional Masking Pathways

Environmental cues (e.g., light-dark cycle) have an immediate and direct effect on behavior, but these cues are also capable of “masking” the expression of the circadian pacemaker, depending on the type of cue presented, the time-of-day when they are presented, and the temporal niche of the organism. Masking is capable of complementing entrainment, the process by which an organism is synchronized to environmental cues, if the cues are presented at an expected or predictable time-of-day, but masking can also disrupt entrainment if the cues are presented at an inappropriate time-of-day. Therefore, masking is independent of but complementary to the biological circadian pacemaker that resides within the brain (i.e., suprachiasmatic nucleus) when exogenous stimuli are presented at predictable times of day. Importantly, environmental cues are capable of either inducing sleep or wakefulness depending on the organism’s temporal niche; therefore, the same presentation of a stimulus can affect behavior quite differently in diurnal vs. nocturnal organisms. There is a growing literature examining the neural mechanisms underlying masking behavior based on the temporal niche of the organism. However, the importance of these mechanisms in governing the daily behaviors of mammals and the possible implications on human health have been gravely overlooked even as modern society enables the manipulation of these environmental cues. Recent publications have demonstrated that the effects of masking weakens significantly with old age resulting in deleterious effects on many behaviors, including sleep and wakefulness. This review will clearly outline the history, definition, and importance of masking, the environmental cues that induce the behavior, the neural mechanisms that drive them, and the possible implications for human health and medicine. New insights about how masking is affected by intrinsically photosensitive retinal ganglion cells, temporal niche, and age will be discussed as each relates to human health. The overarching goals of this review include highlighting the importance of masking in the expression of daily rhythms, elucidating the impact of aging, discussing the relationship between dysfunctional masking behavior and the development of sleep-related disorders, and considering the use of masking as a non-invasive treatment to help treat humans suffering from sleep-related disorders.

High dose melatonin increases sleep duration during nighttime and daytime sleep episodes in older adults

Aging is associated with changes in sleep, and improving sleep may have important consequences for the health, cognition, and quality of life of older adults. Many prescription sleep aids increase the risk of nighttime falls, have adverse effects on next-day cognition, and are associated with increased mortality. Melatonin, a hormone secreted at night, increases sleep duration in young adults but only when administered during the day when endogenous levels are low. In a month-long cross-over study, we randomized 24 healthy older (age >55, mean 64.2 ± 6.3 years) participants to receive 2 weeks of placebo and 2 weeks of either a low (0.3 mg) or high (5.0 mg) dose of melatonin 30 min before lights out. Sleep was polysomnographically recorded and was scheduled during both the biological day and night using a forced desynchrony design. Although 0.3 mg melatonin had a trend towards increasing sleep efficiency (SE) overall, this was due to its effects on sleep during the biological day. In contrast, 5 mg melatonin significantly increased SE during both biological day and night, mainly by increasing the duration of Stage 2 non-rapid eye movement sleep and slightly shortening awakenings. Melatonin should be further explored as a sleep aid for older adults.

Montmorency tart cherry supplementation does not impact sleep, body composition, cellular health, or blood pressure in healthy adults

Background: Sleep disturbances are linked with cardiovascular and metabolic disease as well as poor body composition. Aim: To investigate the use of tart cherry supplements, which are high in antioxidants and may contain melatonin, on parameters of health such as sleep, body composition, cellular health, and blood pressure (BP). Methods: Forty-four participants had completed sleep record data and were included in this analysis. Participants consumed either two 240 ml bottles per day of Montmorency tart cherry (MTC) juice or placebo or two capsules per day of powdered MTC or placebo for 30 days. Participants tracked their sleep daily via questionnaire and completed body composition and BP assessments at baseline, 14 days, and 30 days after supplementation. Results: There were no significant differences in sleep time or quality between groups, though both increased over 30 days. The capsule groups had significantly lower body mass (BM) 14 days versus baseline for placebo group (p = 0.01, mean difference: 0.70 kg) and at 30 days versus 14 days in MTC group (p = 0.02, mean difference: 0.75 kg). No other differences in body composition or cellular health were found. BP was unaffected by MTC supplementation over 30 days. Despite the potential benefits of antioxidants and melatonin, we did not find improvements in sleep time or quality, cellular health or BP in participants consuming MTC for 30 days, though BM decreased in capsule groups. Conclusion: These results conflict with previous data on MTC and sleep and BP, therefore further investigation is warranted.

Melatonin Supplementation in Undetermined Pediatric Deaths

Since 2015, the North Carolina Office of the Chief Medical Examiner has investigated seven deaths of infants and toddlers, ages 2 months to 3 years, with exogenous melatonin detected upon toxicological analysis. Melatonin concentrations ranged from 3-1400 ng/mL in postmortem whole blood. While the cause and the manner of all seven deaths were classified as undetermined, the analytical findings are noteworthy. Melatonin is generally considered a safe, natural product appearing in many over-the-counter supplements geared towards young children to facilitate calmness and improve sleep. Melatonin is a neurohormone, which regulates not only circadian rhythms and natural sleep, but other physiological functions. Endogenous melatonin production, derived from essential amino acid metabolism, does not begin until pineal gland maturation at around three months of age with concentrations in plasma peaking during periods of darkness at approximately 0.2 ng/mL. Administering commercially available melatonin supplements to infants results in levels orders of magnitude greater than endogenous sources which should not be assumed to be safe just because of its endogenous nature. The finding of exogenous concentrations in some postmortem pediatric cases warrants attention. Several topics of interest surrounding these postmortem melatonin findings will be considered, such as minimal regulatory control over commercial products as well as the potential impact on hazardous sleeping conditions. This manuscript will outline the physiological effects of melatonin and detail the case studies from the NC medical examiner system. Forensic toxicology laboratories should consider including melatonin at exogenous concentrations in their testing schemes for appropriate postmortem infant and toddler cases.

Clinical Understanding of the Sleep-Immune Connection

The science of sleep is becoming better understood all the time, and here is a fact that has only recently been revealed: sleep and immune system function have a bidirectional relationship. The disturbance of sleep can create an alteration in immune function. The opposite is also true, in that activation of the immune system can create a disturbance in sleep cycling. This dynamic can ultimately create a feed-forward loop of increasing immune dysfunction and sleep disruption. These systems are intimately intertwined. The clinical approach should be to intervene upstream in the regulation of the fundamental systems that control both sleep and immune function. Through the implementation of this approach, the treatment will focus on the cause of the epigenetic modulation of the sleep-immune system imbalance, and not just its effects and symptomatology.

Melatonin's Benefits and Risks as a Therapy for Sleep Disturbances in the Elderly: Current Insights

Aging is accompanied by circadian changes, including disruptive alterations in the sleep/wake cycle, as well as the beginning of low-degree inflammation ("inflammaging"), a scenario that leads to several chronic illnesses, including cancer, and metabolic, cardiovascular, and neurological dysfunctions. As a result, any effective approach to healthy aging must consider both the correction of circadian disturbance and the control of low-grade inflammation. One of the most important prerequisites for healthy aging is the preservation of robust circadian rhythmicity (particularly of the sleep/wake cycle). Sleep disturbance disrupts various activities in the central nervous system, including waste molecule elimination. Melatonin is a chemical with extraordinary phylogenetic conservation found in all known aerobic creatures whose alteration plays an important role in sleep changes with aging. Every day, the late afternoon/nocturnal surge in pineal melatonin helps to synchronize both the central circadian pacemaker found in the hypothalamic suprachiasmatic nuclei (SCN) and a plethora of peripheral cellular circadian clocks. Melatonin is an example of an endogenous chronobiotic substance that can influence the timing and amplitude of circadian rhythms. Moreover, melatonin is also an excellent anti-inflammatory agent, buffering free radicals, down-regulating proinflammatory cytokines, and reducing insulin resistance, among other things. We present both scientific and clinical evidence that melatonin is a safe drug for treating sleep disturbances in the elderly.

Dietary factors and thyroid dysfunction

Besides iodine deficiency, autoimmune Hashimoto thyroiditis is the leading cause of hypothyroidism globally, characterized by the increased titer of thyroid autoantibodies and destruction of thyroid cells. Graves' disease is the most common etiology of hyperthyroidism worldwide. Patients with thyroid dysfunction often require dietary modifications. Popular interventions include supplementation with certain vitamins and minerals, as well as trace elements such as iodine and selenium. The intake of food containing goitrogens should be limited. Goitrogens are substances of plant origin that interfere with the production of thyroid hormones, increasing the risk for goiter and hypothyroidism. The primary dietary sources of goitrogens are cruciferous vegetables, soy products, starchy plants, and some fruits. Beyond essential nutrients, there has been an increasing interest in using specific nutraceuticals, including myoinositol, Lcarnitine, melatonin, and resveratrol, as potential preventive and therapeutic agents in thyroid diseases. Even though current evidence promotes some beneficial outcomes of these nutraceuticals, further investigations are needed to clarify dose-dependent effects, duration of supplementation, combination in different clinical settings, and the exact mechanism of their action in thyroid disorders.