Circadian variation in urinary melatonin in clinically healthy women in Japan and the United States of America

How Are You Sleeping? Why Nutrition Professionals Should Ask Their Patients About Sleep Habits

Current literature has identified relationships among sleep, nutrition, and diet-related chronic diseases; however, knowledge about how sleep influences diet-related diseases is lacking in dietetics practice. This narrative review briefly explains sleep physiology and outlines the relationships between sleep duration and quality and common nutrition-related diseases, including obesity, diabetes, cardiovascular disease, obstructive sleep apnea, and cancer. Additionally, the review discusses how sleep influences wound healing and pregnancy outcomes and why hospitalized patients are likely to experience sleep problems. Plausible mechanisms explaining the relationships between sleep and disease are presented. Finally, commonly used sleep assessment tools and interventions are reviewed. Given the importance of sleep to health, dietitians should not only be aware of the role sleep plays in disease development and prevention but also assess sleep when feasible and refer patients and clients who are at high risk for sleep problems to a sleep clinic or community program that can address sleep issues.Teaching points:Sleep duration and quality influence risk and outcomes of common nutrition-related diseases.Sleep health evaluation is a missing piece in dietetic practice.There are easy-to-use, validated tools that dietitians can use to screen for sleep problems in order to refer patients and clients to sleep experts.

Decreased Circulating Melatonin with Loss of Age-Related Biphasic Change in Patients with Oral Squamous Cell Carcinoma

Background: Melatonin, produced by the pineal gland, is known for its antioxidant, oncostatic, and anti-inflammatory properties. However, studies on serum melatonin levels in different cancer types have yielded conflicting results, and little is known about the clinical significance of serum melatonin in oral squamous cell carcinoma (OSCC) in the Southern Asian population. Therefore, we explored its role in OSCC in this study. Methods: A total of 67 male OSCC patients and 78 healthy controls were enrolled in this case–control study. The serum levels of melatonin were determined by enzyme-linked immunosorbent assay (ELISA) and compared between the two groups. Results: The serum melatonin levels were significantly lower in OSCC patients compared with healthy controls (mean ± standard deviation, 15.0 ± 4.6 vs. 18.5 ± 11.8 pg/mL, p = 0.02). In the subgroup of age less than 55 years (mean age of OSCC), OSCC patients had a significantly decreased melatonin level than healthy controls (mean melatonin, 15.7 ± 12.6 vs. 20.8 ± 3.9 pg/mL, p = 0.02). Decreased serum melatonin (odds ratio (OR): 0.95, 95%CI: 0.91–0.99), alcohol consumption (OR: 29.02, 95%CI: 11.68–72.16), betel quid chewing (OR:136.44, 95%CI: 39.17–475.27), and cigarette smoking (OR:29.48, 95%CI: 11.06–78.60) all increased the risk of OSCC under univariate analyses of logistic regression. Betel quid chewing (OR: 45.98, 95%CI: 10.34–204.49) and cigarette smoking (OR:6.94, 95%CI: 1.60–30.16) were the independent risk factors for OSCC in Taiwan. In addition, a negative correlation between age and melatonin level was observed in healthy controls (Pearson r = −0.24, p = 0.03). However, the negative correlation was lost in patients with OSCC. Melatonin concentration had no association with the severity of OSCC. Conclusion: Overall, our study provides evidence that serum melatonin levels decreased in OSCC patients in Taiwan and the decreased level is much significant in young populations and suggests that the decreased melatonin was associated with OSCC, especially in young populations. Further studies are warranted to investigate whether melatonin can be a useful non-invasive screening tool for OSCC.

[The role of melatonin as a component of the antioxidant defense system in perimenopausal women with insomnia]

AIM

To determine the ethnic features of the functioning of the 'lipid peroxidation-antioxidants' system and to evaluate the role of melatonin as one of the antioxidant defense system components in Caucasian and Asian perimenopausal women with insomnia.

MATERIAL AND METHODS

One hundred and ten perimenopausal women divided into Caucasian (Russian ethnic group (n=60)) and Asian (Buryat ethnic group (n=50)) were studied. All women underwent clinical-anamnestic examination. Diagnoses of insomnia and obstructive sleep apnea syndrome (OSAS) were made according to the results of specialized somnological questionnaires and polysomnographic monitoring. A multidimensional discriminant analysis was used to reveal the most informative parameters among the hormonal and metabolic parameters studied (melatonin 06.00-07.00h; 12.00-13.00h; 18.00-19.00h; 23.00-00.00h; lipid profile, lipid peroxidation and antioxidant defense system).

RESULTS

The most informative indicators of the metabolic system in Caucasians with insomnia are morning, evening, night melatonin, ketodienes and conjugated trienes, oxidized glutathione (GSSG); with insomnia and OSAS: morning, day, night melatonin, substrates with conjugated double bonds, total cholesterol; in Asian women with insomnia: evening, night melatonin, superoxide dismutase activity (SOD), diene conjugates, active products of thiobarbituric acid, cholesterol of very low density lipoproteins; in women with insomnia and OSAS: morning, day melatonin, SOD, GSSG. The recalculation of the informativeness of each attribute as a percentage showed the prevalence of the influence of the antioxidant protection system parameters over those of lipid peroxidation processes. The contribution of melatonin to the total share of the antioxidant protection system components is more than 60%.

CONCLUSION

Both in Caucasian and Asian women with sleep disorders, there is stress in the antioxidant defense system, where melatonin is the largest contributor.

Sleep duration and the risk of cancer: a systematic review and meta-analysis including dose-response relationship

Background

The effect of sleep duration on cancer risk remains controversial. We aimed to quantify the available evidence on this relationship using categorical and dose–response meta-analyses.

Methods

Population-based cohort studies and case-control studies with at least three categories of sleep duration were identified by searching PubMed, EMBASE, and the Cochrane Library database up to July 2017.

Results

Sixty-five studies from 25 articles were included, involving 1,550,524 participants and 86,201 cancer cases. The categorical meta-analysis revealed that neither short nor long sleep duration was associated with increased cancer risk (short: odds ratio [OR] = 1.01, 95% confidence intervals [CI] = 0.97–1.05; long: OR = 1.02, 95% CI = 0.97–1.07). Subgroup analysis revealed that short sleep duration was associated with cancer risk among Asians (OR = 1.36; 95% CI: 1.02–1.80) and long sleep duration significantly increased the risk of colorectal cancer (OR = 1.21; 95% CI: 1.08–1.34). The dose–response meta-analysis showed no significant relationship between sleep duration and cancer risk. When treated as two linear piecewise functions with a cut point of 7 h, similar nonsignificant associations were found (per 1-h reduction: OR = 1.02, 95% CI = 0.98–1.07; per 1-h increment: OR = 1.003, 95% CI = 0.97–1.03).

Conclusion

Categorical meta-analysis indicated that short sleep duration increased cancer risk in Asians and long sleep duration increased the risk of colorectal cancer, but these findings were not consistent in the dose–response meta-analysis. Long-term randomized controlled trials and well-designed prospective studies are needed to establish causality and to elucidate the mechanism underlying the association between sleep duration and cancer risk.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5025-y) contains supplementary material, which is available to authorized users.

Daytime Circulating Melatonin Levels in Smokers

Aims and background

Melatonin secretion is required to be a potential inhibitor of the development and growth of tumors, and cigarette smoking is a well established risk factor for cancer at various sites.

Methods

Circulating melatonin levels of 20 smokers and 20 non smokers (controls), sampled at the same hour from awaking in order to obtain a comparable circadian synchronization, were compared.

Results

Our data showed higher melatonin circulating levels in smokers (17.44 ±1.8 pg/ml) than in nonsmokers (9.77 ± 1.4 pg/ml).

Conclusions

The causes, mechanism and meaning of this phenomenon are still unknown. The most actractive hypothesis considers higher melatonin levels in smokers as an attempt to counterbalance cellular growth stimulus, a natural “brake” mechanism to restrain the proliferation of normally differentiated tissues: smoke is a prominent risk factor for several different tumors.

Association of the melatonin circadian rhythms with clock 3111T/C gene polymorphism in Caucasian and Asian menopausal women with insomnia

A comparative analysis of melatonin circadian rhythms in Caucasian (incoming population) and Asian (indigenous population) menopausal women with/without sleep disorders depending on the genotype of Clock 3111T/C gene polymorphism was realized.The melatonin level in the saliva was determined four times a day (6:00-7:00, 12:00-13:00, 18:00-19:00, 23:00-00:00 h). The Caucasian women-carriers of the TT-genotype with insomnia as compared to control group-had a higher morning melatonin level and a lower night melatonin level. The Asian women with TT-genotype and insomnia had a lower levels of melatonin as compared to control at daytime, evening and night. A significantly higher melatonin level in the early morning hours was detected in the Caucasian women-carriers of the TT-genotype with insomnia as compared to group womencarriers of the minor 3111C-allele. There were no statistically significant differences in the circadian rhythms of melatonin in the Asian women depending on the genotype of the Clock 3111T/C polymorphism. An assumption with respect to the protective role of the minor allele 3111C in the development of insomnia associated with the displacement of melatonin circadian rhythms in the representatives of the incoming population was made.

Decreased concentration of serum melatonin in nighttime compared with daytime female medical technologists in South Korea

Working during the night can disrupt the normal circadian rhythm by altering the melatonin level. A low level of melatonin is associated with an increased risk of cancer, possibly by decreasing the expression of tumor-suppressor genes, such as p53. To determine whether nighttime work is associated with melatonin level in serum as well as the expression of related genetic markers, we enrolled 100 female nighttime medical technologists employed at a hospital in South Korea. Melatonin concentration and melatonin receptor 1 (MT1) expression were significantly lower in nighttime than in daytime workers (1.84 pg/mL versus 4.04 pg/mL; 1.16 versus 1.61, respectively). However, p53 expression showed no difference between the groups. In summary, nighttime work could be an important risk factor for circadian disruption, but not a direct risk factor for cancer in medical technologists in South Korea.

Racial differences in the association between night shift work and melatonin levels among women

Reduced suppression of melatonin in response to working the night shift among people of Asian ancestry has been suggested as a possible explanation for the null results observed in a recent analysis of shift work and breast cancer risk in a Chinese cohort. The authors analyzed the impact of Asian versus white race on previously reported differences in urinary 6-sulfatoxymelatonin levels in a 2003-2008 study in Seattle, Washington, of female health-care workers that exclusively worked night or day shifts. A total of 225 white and 51 Asian participants were included in the analysis. Although 6-sulfatoxymelatonin levels were affected by night shift work in both racial groups, Asian night shift workers consistently showed 6-sulfatoxymelatonin levels that were closer to levels in day shift workers than did white night shift workers. Furthermore, differences in 6-sulfatoxymelatonin levels between white and Asian night shift workers relative to day shift workers were statistically significant in every instance (P < 0.05). These results suggest that Asians may be better able to maintain a "normal" circadian pattern of melatonin production compared with whites and suggest a biological mechanism by which Asian night shift workers may be at a reduced risk of cancer.

Invited commentary: Shift work and cancer

In this issue of the Journal, Parent et al. (Am J Epidemiol. 2012;176(9):751-759) report significant associations between night-shift work and risk of cancer at several sites among men. These findings not only address the need for shift-work studies that evaluate cancers other than breast and prostate cancer but also support the increasing concern that the negative effects of shift work may be broadly applicable to risk of many cancers via the direct oncostatic properties of melatonin. Studies of shift work have been limited by a lack of detailed data for determining which aspects of this multifaceted exposure may be associated with increased cancer risk. Additionally, the influence of individual-level characteristics, such as preference for daytime activity versus nighttime activity or chronotype, has not been considered. In moving forward, launching new cohort studies of shift work and cancer risk is the most tenable approach, though it will be limited by the years of follow-up required in order to accrue adequate numbers of cancer cases. Studies incorporating biomarkers of effect are useful for providing immediate information that can aid not only in identifying the underlying mechanisms of the shift-work-cancer association but also in interpreting existing epidemiologic data and informing the design of future epidemiologic studies of cancer risk.

Nutritional and lifestyle correlates of the cancer-protective hormone melatonin

CONTEXT

Despite growing support for melatonin as a promising agent for cancer treatment and possibly cancer prevention, few studies have elucidated factors that influence endogenous melatonin. This overview summarizes dietary and lifestyle factors that have been shown to affect circulating melatonin levels.

BIOLOGICAL MECHANISMS

To date, many animal studies and in vitro experiments have illustrated that melatonin possesses oncostatic activity. Mechanisms that are currently being studied include melatonin's activity as an indirect antioxidant and free radical scavenger; its action on the immune system; suppression of fatty acid uptake and metabolism; and its ability to increase the degradation of calmoduline and to induce apoptosis. Studies further suggest that melatonin reduces local estrogen synthesis, through down-regulation of the hypothalamic-pituitary reproductive axis and direct actions of melatonin at the tumor cell level, thus behaving as a SERM.

THERAPEUTIC APPLICATIONS

Several small clinical trials have demonstrated that melatonin has some potential, either alone or in combination with standard cancer therapy, to yield favorable responses. Melatonin or its precursor tryptophan have been found in numerous edible plants, but more studies are needed to evaluate the influence of diets rich in tryptophan and melatonin on circulating melatonin levels in humans. Age, BMI, parity, and the use of certain drugs remain the factors that have been associated most consistently with aMT6s levels.

DISCUSSION

Further insights into the effects of dietary and lifestyle factors that modulate circulating melatonin levels may provide the basis for novel interventions to exploit melatonin for the prevention and treatment of human diseases.

Response of circulating leptin to Ramadan daytime fasting: a circadian study

Although the effects of short-term fasting on serum leptin concentrations are known, those resulting from long-lasting modifications of food intake schedule, as during the month of Ramadan, have not yet been extensively studied. Therefore, serum concentrations of leptin were measured around the clock at 4-hourly intervals before the beginning of Ramadan and on the twenty-third day of Ramadan daytime fasting in ten male subjects keeping the same usual activity pattern and general synchronisation in both situations. Time series were analysed with repeated measures ANOVA and Cosinor. No significant changes in amplitude or 24 h mean concentration were seen, but significant shifts of 5 h 30 min in peak and trough serum leptin levels were found on the twenty-third day of Ramadan.

Aging and the circadian rhythm of melatonin: a cross-sectional study of Chinese subjects 30-110 yr of age

Although previous reports indicate that nocturnal plasma melatonin secretion declines with age, some recent findings do not support this point. In the present cross-sectional study, we documented serum melatonin concentrations at two time points, 02:00 and 08:00 h, in 144 persons aged 30-110 yr and found a significant age-related decline. It began around the age of 60 and reached a very significantly lower level in subjects in their 70s and over 80 yr of age (P < 0.01, when compared with age <60 yr). Nocturnal melatonin levels were higher among (post-menopausal only) women than men overall (P < 0.05). In the older age-groups, nocturnal melatonin levels did not differ between healthy controls and subjects with high blood pressure or ischemic heart disease. To further check these results, we also assessed the circadian pattern of serum melatonin in four subgroups of healthy men, aged 30-39, 40-49, 50-59, and 60-69 yr: blood samples were taken at 2 h intervals from 08:00 to 22:00 h and hourly from 22:00 to 08:00 h. Our results showed generally similar circadian melatonin patterns that peaked at night with very low levels during the daytime. No significant difference was found among the three younger groups, but nocturnal melatonin levels were significantly lower in the men in their 60s.

Stage-dependent depression of melatonin in patients with primary breast cancer. Correlation with prolactin, thyroid stimulating hormone, and steroid receptors

Serum melatonin was determined over 24 hours in 35 patients with breast cancer with either a fresh primary tumor (n = 23) or a secondary tumor (n = 12) and in 28 patients with untreated benign breast disease (controls) having a fibroadenoma (n = 10), fibrocystic mastopathy (n = 14), or other breast diseases (n = 4). Circadian rhythms existed in all groups with acrophases at 2 a.m. A 50% depression of peak and amplitude occurred in the group of patients with primary breast cancer compared with age-matched controls (P less than 0.001, P less than 0.01). The peak declined with increasing tumor size: 27% at Stage T1, 53% at T2 (P less than 0.001), and 73% at T3 (P less than 0.05). In contrast, patients with secondary breast cancer, particularly those receiving antiestrogen therapy, had a melatonin peak similar to controls. These results demonstrated a transient depression of pineal melatonin secretion in primary breast cancer and indicated a dynamic role of the pineal gland in malignancy. To investigate some endocrine effects of a depressed melatonin peak, the 24-hour rhythms of prolactin (PRL) and thyroid stimulating hormone (TSH) were determined in patients with primary breast cancer and compared with patients with secondary breast cancer. The PRL had significant circadian rhythms in both groups; but acrophases occurred at midnight in patients with secondary breast cancer, and there were unusually high concentrations at noon in patients with primary breast cancer. Circadian rhythms were not seen for TSH, but the 24-hour average secretion was depressed by 45% (P less than 0.01) in patients with primary breast cancer. The abnormal concentrations of PRL and TSH in these patients could be due to a depressed melatonin peak normally serving as a central circadian synchronizer and modulator of the secretion of adenohypophysial hormones. Additionally, a positive correlation existed between the nocturnal melatonin peak and progesterone and androgen receptor concentrations in primary tumors indicating a direct involvement of melatonin in the growth control of breast cancer.

Diurnal variation of mood and the cortisol rhythm in depression and normal states of mind

A large scale chronobiological investigation was undertaken in 20 drug-free psychiatric inpatients displaying RDC major depression (endogenous subtype) in comparison to 10 healthy control subjects and 10 of the patients after clinical recovery. A series of measurements was taken 6 times a day and, in 8 of a total of 14 variables, also once a night over a period of 10 to 14 days. The following variables were assessed: mood (three different scales), performance (two tests), motor activity (three measures), salivary flow, urinary excretion of water, sodium, potassium, and free cortisol (UFC), and rectal temperature. A phase chart of the acrophases of the 8 variables with measurements taken during day and night revealed two clusters in the depressives and three in the non-depressed subjects. In the depressives, the acrophases of the mood scales clustered around the time of awakening in the morning, together with the acrophase of UFC, whereas all other acrophases clustered in the afternoon. In the non-depressed subjects, however, the mood scales reached their circadian maxima in the middle of the night around the time when sleep was interrupted to take measurements. All other acrophases corresponded roughly with those found in the depressives. The coincidence of the time course of depressed mood and cortisol excretion in the patients was interpreted as reflecting a temporal relationship between diurnal mood swings in depression and the cortisol rhythm. This interpretation was supported by the significant correlation between the acrophases of the two respective rhythms in patients showing a significant diurnal variation in mood. The mood curves of non-depressed subjects seemed unrelated to the cortisol rhythm. Probably, they mirror diurnal fluctuations of vigilance rather than fluctuations of mood. According to the literature, this rhythm is temporally related to the rhythm of melatonin secretion.

Circadian characteristics of urinary epinephrine and norepinephrine from healthy young women in Japan and U.S.A

Clinically healthy diurnally active young adult women were studied during the same season (March) at the Universities of Kyushu (Fukuoka City, Japan) and of Minnesota (Minneapolis, U.S.A.), under comparable conditions, except that the habitual diets were not changed. The subjects (20 Japanese and 16 Americans of mixed Caucasian background) were studied over a single 24-hr span. Urine was collected at 4-hr intervals. A circadian rhythm in total urinary norepinephrine excretion showed similar characteristics in Japanese and Americans. In epinephrine excretion, the Japanese women showed a statistically significantly higher amplitude with higher peak values, but no statistically significant difference in the rhythm-adjusted mean. This intergroup difference is strictly time dependent; it does not come to the fore in urine samples covering the nocturnal rest span of the subjects.

Plasma and urinary melatonin in male infants during the first 12 months of life

Plasma and urinary melatonin, testosterone and luteinizing hormones were radioimmunologically assayed in 26 male babies during the first year of life. The results show that plasma melatonin levels are low during the phase of postnatal elevation of testosterone and luteinizing hormones. They subsequently increase when testicular activity decreases. Urinary elimination of melatonin does not vary during this period, suggesting the existence of variations in the synthesis or utilization of melatonin.

Urinary melatonin levels in human breast cancer patients

Urinary melatonin levels were measured in 10 postmenopausal Indian women suffering from advanced stages of breast cancer and in 9 well-matched women with non-endocrine complaints, mostly uterovaginal prolapse. Urines of each patient were collected over a period of 2-3 days in four 4-hourly intervals from 6 a.m. to 10 p.m. and one 8-hourly interval from 10 p.m. to 6 a.m. Serum LH, FSH, prolactin, estradiol and cortisol levels at 11 a.m. were determined as well as estrogen and progesterone receptors of the breast tumors. It was found that 24 hour urinary melatonin excretion in cancer patients was on the average 31% decreased as compared to the controls. This change was accompanied by a 33% increase in serum cortisol levels in the cancer patients. The melatonin excretion patterns of the cancer patients were not synchronized as compared to synchronized patterns of the controls. The number of tumors tested for steroid receptors does not yet allow to conclude if melatonin is different in patients with or without hormone-dependent tumors. The data suggest that pineal melatonin secretion may be modified in quantity as well as rhythmicity in breast cancer patients.

Variation of urinary melatonin excretion in humans during the first 30 years of life

Urinary melatonin variation in humans were demonstrated to be a function of age. A radioimmunological assay was used. The values obtained, expressed as nmol x 24 h-1 x kg-1, progressively decreased from birth onwards, with a more accentuated and momentary inflection at the moment of the genital crisis in newborns and at puberty. The results obtained concern only melatonin and not its metabolites, as a result of the high specificity of the antibodies employed.