Melatonin Levels In Patients Research Articles

The Effect of non-surgical periodontal therapy on salivary melatonin levels in patients with chronic periodontitis

The Effect of non-surgical periodontal therapy on salivary melatonin levels in patients with chronic periodontitis

P2-25-4 - Melatonin Secretion in Patients with Breast Cancer Associated with Primary Hypertension

Objective: A number of experimental studies showed that melatonin, the main hormone of the pineal gland, exhibits chronobiological, anticancer and antihypertensive effects. It has been also known that endogenous lithium has similar chronobiological effect. The study was aimed to estimate melatonin secretion and serum levels of endogenous lithium in patients with breast cancer and concomitant primary arterial hypertension.Design and Methods: A total of 18 patients (aged from 37 to 64 years) with breast cancer and concomitant primary arterial hypertension (stage I by Joint National Committee) were studied. Control group was represented by 16 patients (aged from 34 to 69 years) with the same stage of breast cancer. Plasma levels of melatonin were estimated by liquid chromatography, serum levels of endogenous lithium were determined by atomic absorption spectroscopy.Result: Our results showed that plasma melatonin levels in patients with concomitant hypertension was almost 20 times lower (0.11±0.06 pcg/ml) than in control group (2.3< 0,38 pcg/ml, p < 0,01). While serum level of endogenous lithium in patients from control group (0,8 ± 0,03 mmol/l) was within the normal range (0,5 - 1,2 mmol/l), its serum level in patients with both cancer and hypertension was about ten times lower (0,07 ± 0,03 mmol/l, p < 0,001).Conclusion: Melatonin plasma levels and serum concentration of endogenous lithium significantly decrease in patients with breast cancer and arterial hypertension. Taking into consideration that both melatonin and endogenous lithium are chronobiologically active substances, we suggest that disturbances in circadian rhythm might contribute to the pathogenesis of arterial hypertension in patients with breast cancer.

Salivary Melatonin and the Severity of Attachment Loss: A Case-Control Study

Background. Melatonin (MT: N-acetyl-5-methoxytryptamine) is a neuroendocrine hormone secreted mainly by the pineal gland in the brain. MT is produced with a circadian rhythm characterized by elevated blood levels during the night. In healthy individuals, maximal secretion of MT occurs between midnight and 2:00 am, whereas the minimal production occurs during the day. MT can be determined by repeated measurement of plasma or salivary MT or urine sulfatoxy-melatonin. Melatonin has powerful antioxidant effects, has an immunomodulatory role, stimulates the synthesis of type I collagen fibers, and promotes bone formation. Melatonin is also secreted in the saliva, although its role in the mouth is not known well. The purpose of this study was to examine the correlation between salivary melatonin level and periodontal diseases.Methods. Fifty subjects by mean age of40.44±6.38years were equally divided into 5 groups: 10 healthy subjects, 10 subjects with gingivitis, 10 subjects with localized moderate chronic periodontitis, 10 subjects with generalized moderate chronic periodontitis, and 10 subjects with generalized severe chronic periodontitis. Saliva samples were collected from all the subjects and melatonin levels were determined using an enzyme-linked immunosorbent assay. Two-way and one-way ANOVA and Tukey test were used to analyze relationships among variables.Results. Healthy subjects had significantly higher salivary melatonin level (5.29±0.50 pg/mL) compared to patients with gingivitis (4.35±0.30 pg/mL) (P&lt;0.001). The difference between salivary melatonin level in patients with gingivitis and periodontitis was significant (P&lt;0.001). Level of melatonin in patients with generalized severe chronic periodontitis (3.39±0.10 pg/mL) was significantly lower than that in other groups (P&lt;0.01).Conclusions. This study determined that salivary melatonin level in patients with periodontal diseases is lower than that in healthy subjects. Consequently we conclude that there is a negative correlation between melatonin level and the severity of disease, suggesting that melatonin might have a protective role against periodontal diseases, although further research is required to validate this hypothesis.

Reduction of Melatonin Level in Patients with Type II Diabetes and Periodontal Diseases.

Background and aims. Melatonin is a circulating hormone that is mainly released from the pineal gland. It possesses antioxidant, free-radical scavenging, and immune-enhancing properties. A growing number of studies reveal a complex role for melatonin in influencing various diseases, including diabetes and periodontal diseases. The aim of this study was to examine the possible links between salivary melatonin levels and type II diabetes and periodontal diseases.Materials and methods. A total of 30 type II diabetic patients, 30 patients with periodontal diseases, 30 type II diabetic patients with periodontal disease and 30 age- and BMI-matched controls were studied. The periodontal status was evaluated by the Community Periodontal Index (CPI). Salivary melatonin levels were determined by a commercial enzyme-linked immunosorbent assay (ELISA) kit.Results. The mean of salivary melatonin level was significantly lower in patients with either periodontitis or diabetes compared to healthy subjects (P < 0.05). Salivary melatonin concentration decreased in type II diabetic patients and periodontitis patients, and then decreased reaching the lowest levels in type II diabetic patients with periodontal disease.Conclusion. Based on the results of this study, it can probably be concluded that salivary level of melatonin has an important role in the pathogenesis of diabetes and periodontal diseases. It is also worth noting that this factor could probably be used as a pivotal biological marker in the diagnosis and possible treatment of these diseases, although further research is required to validate this hypothesis.

Preliminary study: Evaluation of melatonin secretion in children and adolescents with type 1 diabetes mellitus.

Objective:Melatonin is an indolamine hormone, synthesized from tryptophan in the pineal gland primarily. Melatonin exerts both antioxidative and immunoregulatory roles but little is known about melatonin secretion in patients with type 1 diabetes mellitus (T1DM). The aim of this study was to measure serum melatonin levels in patients with T1DM and investigates their relationship with type 1 diabetes mellitus.Materials and Methods:Forty children and adolescents with T1DM (18 boys and 22 girls) and 30 healthy control subjects (17 boys and 13 girls) participated in the study. All patients followed in Pediatric Endocrinology and Metabolism Unit of Gaziantep University Faculty of Medicine and also control subjects had no hypertension, obesity, hyperlipidemia, anemia, and infection. Blood samples were collected during routine analysis, after overnight fasting. Serum melatonin levels were analyzed with ELISA.Results:There were no statistically significant differences related with age, sex, BMI distribution between diabetic group and control group. Mean diabetic duration was 2.89 ± 2.69 years. The variables were in the equation. Mean melatonin level in diabetic group was 6.75 ± 3.52 pg/ml and mean melatonin level in control group was 11.51 ± 4.74 pg/ml. Melatonin levels were significantly lower in diabetic group compared to controls (P < 0.01).Conclusions:Melatonin was associated with type 1 diabetes mellitus significantly. Because of the varied roles of melatonin in human metabolic rhythms, these results suggest a role of melatonin in maintaining normal rhythmicity. Melatonin may play role in preventing process of inflammation and oxidative stress.

Effect of topical application of melatonin to the gingiva on salivary osteoprotegerin, RANKL and melatonin levels in patients with diabetes and periodontal disease

This cross-section study was designed to assess the effect of topical application of melatonin to the gingiva on salivary RANKL, osteoprotegrin (OPG) and melatonin levels as well as plasma melatonin in 30 patients with diabetes and periodontal disease and in a control group of 30 healthy subjects. Salivary RANKL and OPG were measured by enzyme-linked immunosorbent assay and salivary and plasma melatonin by radioimmunoassay using commercial kits. Periodontograms were performed using the Florida Probe(®). Diabetic patients were treated with topical application of melatonin (1% orabase cream formula) once daily for 20 days. Patients with diabetes showed significantly higher mean levels of salivary RANKL than healthy subjects as well as significantly lower values of salivary OPG and salivary and plasma melatonin. After treatment with melatonin, there was a statistically significant decrease of the gingival index, pocket depth and salivary levels of RANKL, and a significant rise in salivary values of OPG. Changes of salivary OPG levels before and after topical melatonin treatment correlated significantly with changes in the gingival index and pocket depth. Treatment with topical melatonin was associated with an improvement in the gingival index and pocket depth, a reduction in salivary concentrations of RANKL and increase in salivary concentrations of OPG, which indicates that melatonin has a favorable effect in slowing osteoclastogenesis, improving the quality of alveolar bone and preventing the progression of periodontal disease.

Global left ventricular longitudinal strain is associated with decreased melatonin levels in patients with acute myocardial infarction: a two-dimensional speckle tracking study

Low circulating melatonin levels predict poor outcome in patients with ST-segment elevation myocardial infarction (STEMI). In the present study, we investigated whether a relationship between myocardial deformation in parameters measured by echocardiography and circulating melatonin level exists. We prospectively included 112 patients with STEMI who performed echocardiography and simultaneous measurement of serum melatonin, during the light period within 72 h of admission. We found a negative correlation between circulating melatonin levels and global longitudinal strain (p = 0.006, r = −0.33). In conclusion, melatonin levels have a correlation with two-dimensional speckle tracking in patients with STEMI.

Melatonin in headache disorders

Melatonin have diverse physiological functions, including the control of circadian rhythms, sleep regulation, enhancement of immunological functioning, free radical scavenging and antioxidant effects, inhibition of oncogenesis, mood regulation, vasoregulation, regulation of seasonal reproductive activity and analgesia. Melatonin also have several actions within the central nervous system and in the pathophysiology of headaches, which include an anti-inflammatory effect, toxic free radical scavenging, reduction of proinflammatory cytokine up-regulation, nitric oxide synthase activity and dopamine release inhibition, membrane stabilization, GABA and opioid analgesia potentiation, glutamate neurotoxicity protection, neurovascular regulation, serotonin modulation, and the similarity of chemical structure to that of indomethacin. A relation with seasonal and circadian pattern has been observed in cluster an hypnic headache. The literature of headache is convergent in pointing to low levels of melatonin in patients with migraine and cluster headache. Treatment of headache disorders with melatonin and other chronobiotic agents is promising. Some trials showed that melatonin was effective in cluster headache and migraine prevention but future studies are necessary for the better understanding of the role of melatonin in headache disorders treatment.

Morning and nocturnal serum melatonin rhythm levels in patients with major depressive disorder: an analytical cross-sectional study.

The pineal gland is an adaptive organ that precisely regulates the biological rhythms of melatonin brain hemostasis. Variation in the regulation of melatonin rhythms is a likely cause of depressive disorder. The purpose of this study was to measure serum melatonin levels in patients with major depressive disorder (MDD) and normal control subjects. Analytical cross-sectional study at the industrial medical unit of the Iron Smelting Company of Isfahan, Iran. The morning and nocturnal serum melatonin levels of patients and controls were measured using the enzyme-linked immunosorbent assay (ELISA) method. All data were assessed using variance analysis. The morning and nocturnal serum melatonin levels of depressed and healthy subjects differed (P < 0.05). The nocturnal serum melatonin levels of depressed women were lower than those of depressed men (P < 0.05). The findings of this study showed that the nocturnal serum melatonin levels in the depressed patients were lower than in the controls. Thus, the peak melatonin phase in the depressed patients was reached with delay.

A Preliminary Study of Fluvoxamine Maleate on Depressive State and Serum Melatonin Levels in Patients after Cerebral Infarction

Antidepressants have been recommended for the treatment of post-stroke depression (PSD). The purpose of this study was to evaluate the effect of fluvoxamine maleate, a selective serotonin re-uptake inhibitor (SSRI), on depressive state, sleep disturbance, and serum melatonin levels in patients with depressive state after cerebral infarction. Nineteen patients who were hospitalized for cerebral infarction and scored 40 points or higher on the Self Depression Scale (SDS) were enrolled in this study. Nine of the 19 patients received fluvoxamine as a treatment group and the other 10 patients were used as untreated controls. Before and after commencing the drug therapy, the patients were assessed by the SDS, Pittsburgh Sleep Quality Index (PSQI), Japan Stroke Scale for Depression (JSSD), and Japan Stroke Scale for Emotional Disturbance (JSSE), and their serum melatonin levels were measured. The control group underwent the same evaluations as the treatment group. The SDS score improved in the treatment group at 1 week after the start of drug treatment, and in the control group at 1 and 2 weeks into the observation period. In the treatment group, the JSSD and PSQI scores improved and serum melatonin levels increased. The administration of fluvoxamine to patients with depressive state after cerebral infarction alleviated both the depressive state and sleep disturbances. Increased melatonin levels by the administration of fluvoxamine may contribute to improvement in sleep disturbance, one of the major symptoms of depression.

Melatonin levels in premenopausal women with fibromyalgia syndrome

The fibromyalgia syndrome (FMS) is a chronic, widespread pain disorder of unknown etiology. It has been suggest that familial component, environmental factors, endocrine and neurotransmitter alterations, and psychological factors may contribute to the development of FMS. The role of melatonin in FMS is unclear. Some studies describe a lower nocturnal peak and a decreased secretion of melatonin in women with FMS when compared with healthy matched controls. The aim of the present study was to determine the possible role of melatonin in FMS patients. We examined the characteristics and levels of melatonin in 25 consecutive premenopausal women with FMS. Serum blood samples were collected from 25 patients and 20 the age and gender matched healthy controls. Melatonin levels were measured by enzyme-linked immunosorbent assay. Then, the results were compared with those from healthy subjects. Serum melatonin levels of FMS patients were not statistically different from those of controls (P > 0.05). No association was observed between melatonin levels of patients with FMS and disease duration, sleep disturbances, fatigue, and pain scores. Our results demonstrate that melatonin levels were similar in patients with FMS and healthy controls. Further studies are needed to determine the possible role of melatonin.

Melatonin and Its Day and Night Rhythm of Alterations in Familial Mediterranean Fever: A Brief Research Letter

Objective: The pineal hormone melatonin plays a crucial role in immunomodulation, mainly by effecting T cells. The aims of the present study were to compare the melatonin levels in patients with Familial Mediterranean Fever (FMF) and healthy controls and to find out if it associates with interferon(IFN)γ and interleukin(IL)-10.Materials and Methodology: Twenty five patients with FMF and 16 healthy donors were enrolled into the study. Melatonin, IFN γ and IL-10 measurements were assayed by using enzyme immunoassay (EIA) method.Results: Serum melatonin levels at 03.30 am in both patients during attack-free phase and healthy controls were significantly higher than those levels of corresponding groups measured at 10.00 am. The melatonin levels at 03.30 and 10.00 am in patients during attack-free phase were higher than those levels measured in healthy controls at the same time points. IFNγ and IL-10 did not show any day and night rhythm in both patients and healthy controls. In addition, there was no association among day and night levels of melatonin, IFNγ and IL-10.Conclusions: We conclude that melatonin may play a role in FMF pathogenesis. However, its modulatory effect on immune response most likely does not depend on T cells. Further comprehensive studies should be performed in order to reveal the role of melatonin in the pathogenesis of this disease.

Serum melatonin level and oxidative stress in sickle cell anemia

This study evaluated serum melatonin levels in patients with sickle cell anemia (SCA) and compared the results to lipid peroxidation by determining thiobarbituric acid-reactive substances (TBARS) and Trolox equivalent antioxidant capacity (TEAC). The group studied was composed of 15 SCA patients and 24 subjects without hemoglobinopathies. The average melatonin level was significantly reduced in the SCA patients ( p < 0.001) when compared to the control group. The SCA patients showed significantly higher values for TBARS and TEAC when compared to values obtained for the control group ( p < 0.001 and p < 0.01). Results from the correlation analysis in the SCA group were not statistically significant for any parameters except for TBARS and TEAC levels, which had a positive correlation ( r = 0.51; p = 0.04), suggesting the participation of melatonin in antioxidant defense. The use of melatonin could be a possible therapeutic target for improving antioxidant defense and to reduce oxidative damage, alleviating symptoms associated with SCA.

Antioxidant enzymes and melatonin levels in patients with bronchial asthma and chronic obstructive pulmonary disease during stable and exacerbation periods

An imbalance between oxidative stress and antioxidative capacity may play an important role in the development and progression of bronchial asthma (BA) and chronic obstructive pulmonary disease (COPD). We carried out a study to assess the systemic oxidant-antioxidant status during the exacerbation and the stable period in patients with BA and COPD. A total of 33 patients, 16 with BA and 17 with COPD were included in the study. During the exacerbation and the stable periods, levels of malondialdehyde (MDA), activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GRd), and catalase (CAT) in erythrocytes and serum melatonin concentrations were investigated. Blood counts, respiratory functions, and blood gases of the patients were also performed. During an exacerbation period of BA, despite the decreases in GSH-Px, GRd and melatonin levels, MDA and CAT levels, and the white blood cell count, the percentage of eosinophils were significantly higher than in the stable period. Also, it was found that FEV(1)/L (where FEV(1) is the forced expiratory volume in 1 s), FVC/L (where FVC is forced vital capacity), PEF/L/s (where PEF is peak expiratory flow), pO(2) (where pO(2) is oxygen pressure) levels increased during the stable period in patients with BA. MDA and SOD values were higher in the exacerbation period than in the stable period although GSH-Px, GRd, melatonin, pH, and pO(2) values were lower in the exacerbation period than in the stable period. The blood counts and the respiratory function tests did not change between the exacerbation and the stable period of patients with COPD significantly. In conclusion, we observed that oxidative stress in the exacerbation period of patients with BA and COPD increased whereas the antioxidant enzymes and melatonin values reduced. The episodes of BA or COPD might be associated with elevated levels of oxidative stress.

Daytime levels of melatonin in patients with age‐related macular degeneration

Melatonin (N-acetyl-5-methoxytryptamine) (MT) is a hormone that acts as an antioxidant. It is produced by the pineal gland and within the retina; its release is blocked by light entering the eye. We examined whether MT daytime levels differ between pseudophakic patients with age-related macular degeneration (ARMD) and pseudophakic subjects without any ocular pathology of the same age. A prospective, cross-sectional, observational study was performed. Pseudophakic patients of the same age group were included. Patients underwent complete ophthalmic examinations and blood sampling between 08:00 and 10:00 hr. MT daytime value in the serum was the main outcome measure. Sixty-nine pseudophakic patients were included. Fifty patients with exudative and non-exudative ARMD were in the study group while 19 patients were controls. Patients with ARMD had significantly higher daytime levels of MT (P = 0.003). There were significant differences in MT daytime levels between the exudative and non-exudative forms (P = 0.009). MT values also correlated with the best-corrected visual acuity (r = -0.285, P = 0.019). These data indicate that pseudophakic patients with ARMD produce more MT during the day compared to pseudophakic subjects without ARMD. This may be caused by the reduced visual acuity in patients with ARMD, whereby less light reaches the photoreceptors, allowing MT secretion to continue during the day. Because MT also acts as an antioxidant and daytime levels are higher in patients with ARMD, these results might be interpreted as a rescue factor.

Blood 5‐hydroxytryptamine, 5‐hydroxyindoleacetic acid and melatonin levels in patients with either Huntington's disease or chronic brain injury

Following a study of oxidative tryptophan metabolism to kynurenines, we have now analysed the blood of patients with either Huntington's disease or traumatic brain injury for levels of 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and melatonin. There were no differences in the baseline levels of these compounds between patients and healthy controls. Tryptophan depletion did not reduce 5-HT levels in either the controls or in the patients with Huntington's disease, but it increased 5-HT levels in patients with brain injury and lowered 5-HIAA in the control and Huntington's disease groups. An oral tryptophan load did not modify 5-HT levels in the patients but increased 5-HT in control subjects. The tryptophan load restored 5-HIAA to baseline levels in controls and patients with brain injury, but not in those with Huntington's disease, in whom 5-HIAA remained significantly depressed. Melatonin levels increased on tryptophan loading in all subjects, with levels in patients with brain injury increasing significantly more than in controls. Baseline levels of neopterin and lipid peroxidation products were higher in patients than in controls. It is concluded that both groups of patients exhibit abnormalities in tryptophan metabolism, which may be related to increased inflammatory status and oxidative stress. Interactions between the kynurenine, 5-HT and melatonin pathways should be considered when interpreting changes of tryptophan metabolism.

A comparison of the circadian rhythms and the levels of melatonin in patients with diurnal and nocturnal complex partial seizures

The aim of the present work was to assess serum melatonin levels and melatonin circadian rhythm in patients with diurnal and nocturnal complex partial epilepsy. Daily rhythms of melatonin were studied in patients with diurnal complex partial epilepsy ( n = 10), patients with nocturnal complex partial epilepsy ( n = 10), and a control group ( n = 10). All patients were under carbamazepine treatment. Serum melatonin samples were taken at 1000, 2200, 0100, and 0500 hours. We found that melatonin circadian rhythm was normal in all patients when compared with controls. Melatonin levels were low in both patients with nocturnal and patients with diurnal complex partial epilepsy compared with the control group at 1000, 2200, 0100, and 0500 hours; a statistically significant decrease in melatonin levels was observed in the patients with epilepsy at 1000 hours only. These findings suggest that melatonin levels and circadian rhythm of melatonin do not differ between patients with nocturnal and patients with diurnal complex partial epilepsy. Further detailed research is necessary to determine the factors that govern the nocturnal or diurnal occurrence of complex partial seizures.

Melatonin signaling dysfunction in adolescent idiopathic scoliosis.

In vitro assays were performed with bone-forming cells isolated from 41 patients with adolescent idiopathic scoliosis and 17 control patients exhibiting another type of scoliosis or none. To determine whether a dysfunction of the melatonin-signaling pathway in tissues targeted by this hormone is involved in adolescent idiopathic scoliosis. Pinealectomy in chicken has led to the formation of a scoliotic deformity, thereby suggesting that a melatonin deficiency may be at the source of adolescent idiopathic scoliosis. However, the relevance of melatonin in the etiopathogenesis of that condition is controversial because most studies have reported no significant change in circulating levels of melatonin in patients with adolescent idiopathic scoliosis. Primary osteoblast cultures prepared from bone specimens obtained intraoperatively during spine surgeries were used to test the ability of melatonin and Gpp(NH)p, a GTP analogue, to block cAMP accumulation induced by forskolin. In parallel, melatonin receptor and Gi protein functions were evaluated by immunohistochemistry and by coimmunoprecipitation experiments. The cAMP assays demonstrated that melatonin signaling was impaired in osteoblasts isolated from adolescent idiopathic scoliosis patients to different degrees allowing their classification in 3 distinct groups based on their responsiveness to melatonin or Gpp(NH)p. Melatonin signaling is clearly impaired in osteoblasts of all patients with adolescent idiopathic scoliosis tested. Classification of patients with adolescent idiopathic scoliosis in 3 groups based on functional in vitro assays suggests the presence of distinct mutations interfering with the melatonin signal transduction. Posttranslational modifications affecting Gi protein function, such as serine residues phosphorylation, should be considered as one possible mechanism in the etiopathogenesis of AIS.

Serum melatonin levels following enucleation and transpupillary thermotherapy in patients with choroidal melanoma.

To study serum melatonin levels in patients with choroidal melanoma preoperatively and following enucleation and transpupillary thermotherapy. Forty patients with preoperative choroidal melanoma were included in the study. Of these, 15 patients underwent enucleation (group 1) and 25 patients received transpupillary thermotherapy (group 2). A further 20 patients without melanoma acted as age-matched controls. Serum melatonin levels were determined 1 day preoperatively, and at the first and sixth months postoperatively using ELISA. Preoperative serum melatonin levels were highest in group 2 followed by group 1, but this was not statistically significant compared to controls. Postoperatively, a constant decrease of serum melatonin was observed in both groups after the first month, which reached statistical significance at the sixth month (P = 0.003). Also, a significant regression in tumour thickness was documented in group 2 (P = 0.003). Three patients in group 1 developed hepatic metastases. Patients with choroidal melanomas had higher levels of serum melatonin compared to individuals without tumours. Smaller tumours were associated with more elevated melatonin levels compared to larger tumours. Serum melatonin levels fell considerably following enucleation and transpupillary thermotherapy.

Elevated Serum Melatonin is Associated with the Nocturnal Worsening of Asthma

<h2>Abstract</h2><h3>Background</h3> Increased airway inflammation at night contributes to the nocturnal worsening of asthma. In vitro studies have shown exogenous melatonin to be pro-inflammatory in asthma, but it is unknown whether endogenous melatonin levels are a controller of airway inflammation in nocturnal asthma. <h3>Objective</h3> Our aim was to determine 24-hour patterns of serum melatonin and their relationship to overnight decline in physiology in subjects with nocturnal asthma, non-nocturnal asthma, and in healthy controls. <h3>Methods</h3> Observational study of pulmonary physiology and melatonin levels in patients with nocturnal asthma (n = 7), non-nocturnal asthma (n = 13), and healthy controls (n = 11). Subjects maintained a constant sleep–wake regimen for 7 days. On day 8, serum melatonin was measured every 2 hours by radioimmunoassay and analyzed by cosinor modeling. The correlation between serum melatonin levels and overnight change in spirometry was evaluated by Spearman's rank correlation analysis. <h3>Results</h3> In subjects with nocturnal asthma, peak melatonin levels were significantly elevated compared with healthy controls (67.6 ± 5.0 pg/mL versus 53.5 ± 4.0 pg/mL, <i>P</i> = .03). Melatonin acrophase was delayed in nocturnal asthma (02:54 versus 01:58 in healthy controls, <i>P</i> = .003, and 02:15 in non-nocturnal asthma, <i>P</i> = .01). In subjects with nocturnal asthma, increasing melatonin levels were significantly and inversely correlated with overnight change in FEV₁ (<i>r</i> = −.79, <i>P</i> = .04), a relationship that was not observed in non-nocturnal asthma or healthy controls. <h3>Conclusions</h3> Nocturnal asthma is associated with elevation and phase delay of peak serum melatonin levels. Elevated melatonin levels might contribute to the pathogenesis of nocturnal asthma.