Summary
Sleep
Sleep is reversible, periodic and recurring state in which consciousness and muscular activity is temporarily suspended or diminished, and responsiveness to outside stimuli is reduced.
Mechanism of sleep:
The ventro-lateral pre-optic nucleus (VLPO ) of the hypothalamus is often referred to as the “sleep switch” .This area becomes active during sleep and uses the inhibitory neurotransmitter GABA and galanin to initiate sleep by inhibiting the arousal regions of the brain . Waking usually transitions into light NREM sleep.
Stages of Sleep:
Sleep usually transitions into two stages: rapid eye movement (REM) sleep and non-rapid eye movement (non-REM or NREM) sleep.
NREM sleep:
NREM is divided into three stages: N1, N2, and N3, the last of which is also called delta sleep or slow-wave sleep.The whole period normally proceeds in the order: N1 → N2 → N3 → N2 → REM. There is a greater amount of deep sleep (stage N3) earlier in the night.
NREM is an active state that is maintained through oscillation between thalamus and cortex. There are several theories about the function of NREM stage .one theory proposed that decreased metabolic demand facilitates the replenishment of glycogen stores.
REM sleep:
REM sleep dominates the latter half of the sleep period, especially the hours before waking, and the REM component of each sleep cycle typically increases as the night goes on.
It is associated with rapid (and apparently random) side-to-side movements of the closed eye. This eye motion is not constant (tonic) but intermittent (phasic).REM sleep is activated by secretion of the neurotransmitter acetylcholine and inhibited by the neurotransmitter serotonin, and this effect is principally generated in the pons region of the brainstem.
Obesity
Obesity is defined as abnormal or excessive accumulation of fat that may impair health. It is defined as the weight in kilograms divided by the square of the height in meters (kg/m2).
By 2018, approximately 2.8 billion adults will be overweight and more than 700 million will be obese. Obesity is a growing epidemic that affect women more than men .Egypt is the fattest African country. It is also the 14th fattest country in the world, With nearly 70 percent of its adult population overweight or obese.
Reaven ,et al.1988 used the term "syndrome X" to describe the close interrelationship among obesity, hyperinsulinemia , glucose intolerance, and dyslipidemia .Obesity is one of the leading preventable causes of death worldwide. The mortality risk is lowest at a BMI of 20 –25 kg/m2 in non-smokers and at 24 – 27 kg/m2 in current smokers, with risk increasing along with changes in either direction.
Possible mechanisms that link sleep and obesity may include , Sleep deprivation may lead to increased caloric intake due to increased hunger and/or increased opportunity to eat. It is also possible that sleep deprivation could cause decreased energy expenditure through altered thermoregulation and increased fatigue.
Spiegel et al. 1999 found that Young men limited to 4 hours of sleep a night for 6 days had a 40% decrease in the rate of glucose clearance and a 30% decrease in insulin response . This diabetic-like response to sleep deprivation is one possible mechanism linking sleep to obesity. The sleep debt decreases leptin, a hormone secreted by adipose tissue and is involved in signaling satiety. A decrease in leptin thus leads to increases in hunger.Plasma leptin reaches a maximum level midway through the normal sleep period. The increase in hunger is also partly due to an increase in plasma ghrelin, a hormone that is secreted by the stomach. Chaput et al. 2007 also found that short sleep duration was associated with suppressed leptin.
The present study provides a cross sectional examination of the profile of sleep in obese patients during the period of August 2015 till Febreuary 2016 . So we recruited 50 obese patients and 20 non obese patients comparable controls. 50 cases of females with age range (18-55) years and control patients were of comparable age and sex.
We hypothesized that some sleep disorders like (decreased total sleep time ,more awakenings,shortened REM latency) incidence increases with obesity according to increasing its grade.
Therefore , the aim of our work was to study the effect of sleep disorders on developing obesity, to investigate the effect of obesity on sleep duration and developing sleep disorders.
SUBJECTS AND METHODS
Study design:
Descriptive ,cross- sectional and comparative study.
Setting of the study:
The internal medicine out patient clinic and Department in Benha University Hospital and private obesity clinics.
Selection of cases:
A)Sample selection:
A convenient sample of 50 patients were selected from the outpatient clinic of Internal medicine in Banha University Hospital ,All inpatients fulfilling the inclusion criteria .
B) Inclusion criteria:
• Age :18 -55.
• Gender :females.
• Diagnosed primarily obese according to :Body Mass Index (BMI) and Waist to Hip ratio (W/H),Body Metabolic Rate (BMR).
c) Exclusion criteria:
• Presence of mental retardation, developmental disability and neurological disorder or psychatric disorder.
• Presence of endocrinal or genetic disease causing obesity.
• Presence of any medical condition or drug administration which can disturb sleep.
D)Control group:
A control group of 20 females of volunteers matched with the patient group for age and sex with the same exclusion criteria of patients with no apparent physical or psychiatric morbidity .
Procedures:
Study proper:
I) An informed written consent was obtained from all participants in the study before conducting the interviews.
II) Patients group of the study were subjected to the following:
1) Semi-structured Interview questionnaire: to an idea about the patient`s past and family history.
2) Body Mass Index (BMI) and Waist Hip Ratio (WHR) :calculated to detect whether the patient is obese or not.
3) Standardized Structured Sleep Questionnaire (Assad and kahla, 2009): for the assessment of subjective sleep complaints in those patients.
III) Control group individuals : were subjected to all previous procedures as the patients groups but after excluding the exclusion criteria.
Statistical analysis:
The collected data were tabulated and analyzed using Statistical Package for Social Science version 16 soft ware (Spss Inc, Chicago, ILL Company).
The following statistical procedures have been used in this work:
1) Independent sample T-test: It compares between 2 means of 2 independent groups. T-value is the ratio of the difference between the two means/calculated SD of this difference.
1. Pearson’s Product correlation coefficient:it evaluates the linear association between 2 quantitative variables ( one is the independent variant.X, and the other is the dependent variant, Y).
2. ANOVA (F test) : It compares between more than 2 continuous variables expressed as mean ± SD, (F) is the ratio between variation due to the studied variable to variation due to error. The more the value of (F) the more significant is the result.
3. Fisher's exact test : It is used when you have two nominal variables. Fisher's exact test is more accurate than the chi-squared test when the expected numbers are small.
4. P value: Used to indicate the level of significance
• P value >0.05 is non significant (NS).
• P |
