Author: Ng, Yue Hum Fantas
Title: Assessment of melatonin and its association with sleep in metabolic syndrome
Degree: M.Sc.
Year: 2014
Subject: Melatonin -- Physiological effect.
Metabolic syndrome.
Hong Kong Polytechnic University -- Dissertations
Department: Department of Health Technology and Informatics
Pages: x, 75 leaves : ill. ; 30 cm.
Language: English
Abstract: According to World Health Organization (WHO), there were 17.3 million people died from cardiovascular disease (CVD) in 2008 worldwide and currently there were 347 million people affected by diabetes mellitus (DM). The prevalence of CVD and DM was increasing in an alarming rate and both risk factors were associated with metabolic syndrome (MS). Metabolic syndrome was a combination of metabolic abnormalities including dyslipidemia, hyperglycemia, high blood pressure and central obesity. In addition, subjects affected by MS were also associated with sleep deprivation. Shortened sleep time and poor quality of sleep had been shown to cause an increase in food intake and higher blood pressure which were the risk factors associated with MS. In Hong Kong, the prevalence of MS was increasing from 9.6% in 1990s to 23% in 2001. This surge of MS required immediate attention and quicker method to diagnose MS was needed to stop the uprising of MS in the future. Melatonin had been shown to promote sleep and curtail MS. By evaluating melatonin levels with subjects with and without MS may provide a quicker mean of predicting MS. The objective of this study was to evaluate sleep biomarker, melatonin and its association with sleep in a total of forty Hong Kong Chinese subjects with and without MS. Enzyme-linked immunosorbent assay (ELISA) was used to measure the plasma melatonin concentration and Pittsburgh Sleep Quality Index (PSQI) questionnaires were used to evaluate the sleep quality and sleep duration for all the study subjects.
Subjects with MS had significant lower levels of melatonin than subjects without MS (4.06±0.47 versus 6.10±0.45, p=0.003) as expected since melatonin helped with curtailing MS and subjects with MS had been shown to have lower circulating melatonin. There was a positive correlation between melatonin levels and High-Density Lipoprotein Cholesterol (HDL) with p=0.04. However there was no significant difference between quality of sleep and duration of sleep with melatonin levels for this study (p=0.415 and p=0.101). There was also no significant difference between quality of sleep and duration of sleep while comparing to subjects with and without MS (p=0.324 and p=0.206). Lower plasma melatonin levels in MS subjects suggested melatonin may involve with pathogenesis of MS. Melatonin therapy had been shown to help subjects with MS to decrease blood pressures, lose weight and improve lipid profile. The reason for no significant difference between sleep quality, sleep duration and melatonin level may be due to limitation of this study. The optimal way to evaluate melatonin levels was before going to bed and after waking up. The best way to evaluate sleep was using sleep actigraphs or full polysomnography. Numerous clinical trials had examined the therapeutic values of melatonin in various diseases such as cardiovascular diseases, diabetes and sleep disturbances but no clinical trial had been done to use melatonin as biomarker to predict MS. More clinical trials with larger population would be needed to investigate melatonin involvement in MS and found the definite pathophysiologic role in human.
Rights: All rights reserved
Access: restricted access

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