Section on Neuroendocrinology of Obesity

Bethesda, MD, United States

Section on Neuroendocrinology of Obesity

Bethesda, MD, United States

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Cizza G.,Section on Neuroendocrinology of Obesity | De Jonge L.,Section on Neuroendocrinology of Obesity | Piaggi P.,University of Pisa | Piaggi P.,Obesity and Diabetes Clinical Research Section | And 7 more authors.
Metabolic Syndrome and Related Disorders | Year: 2014

Background: The constellation of metabolic syndrome, although controversial with regard to its clinical usefulness, is epidemiologically related to increased diabetes risk and cardiovascular mortality. Our goal was to investigate the associations among neck circumference (NC), obstructive sleep apnea syndromes (OSAS), and metabolic syndrome in obese men and women sleeping less than 6.5hr per night. Methods: This was a cross-sectional study of obese men and premenopausal obese women sleeping less than 6.5hr per night. We enrolled 120 individuals (92 women), age 40.5±6.9 years and body mass index (BMI) 38.6±6.5kg/m2. Metabolic syndrome severity was assessed by a score and OSAS was defined as a respiratory disturbance index (RDI) ≥5. Metabolic end endocrine parameters were measured, and sleep duration was determined by actigraphy and validated questionnaires. Results: Metabolic syndrome was found in 41% and OSAS in 58% (28% had both). Subjects with metabolic syndrome were 3 years older and more often Caucasian; they had higher RDI scores, larger NC, more visceral fat, lower serum adiponectin, higher 24-hr urinary norepinephrine (NE) excretion, and lower growth hormone concentrations. A NC of ≥38cm had a sensitivity of 54% and 58% and a specificity of 70% and 79% in predicting the presence of metabolic syndrome and OSAS, respectively. RDI, adiponectin, and NC accounted for approximately 30% of the variability in the metabolic syndrome score, as estimated by an age-, gender-, and race-corrected multivariate model (R2=0.376, P<0.001). Conclusion: Greater NC is associated with OSAS and metabolic syndrome in short-sleeping obese men and premenopausal obese women. Addition of NC to the definition of metabolic syndrome should be considered and needs to be validated in future studies. © Copyright 2014, Mary Ann Liebert, Inc. 2014.


Knutson K.L.,University of Chicago | Zhao X.,Section on Neuroendocrinology of Obesity | Mattingly M.,Section on Neuroendocrinology of Obesity | Galli G.,Section on Neuroendocrinology of Obesity | And 2 more authors.
Sleep Medicine | Year: 2012

Background: Sleep disordered breathing (SDB) is common in obese adults, but not all obese adults have SDB. The aim of these analyses was to determine what predicted SDB in a sample of obese adults. Methods: We conducted cross-sectional analysis of 139 obese men and women aged 18-50years who are chronic short sleepers. Habitual sleep duration and sleep efficiency were estimated using two weeks of wrist actigraphy. Respiratory disturbance index (RDI) was assessed by a portable screening device. SDB was defined as RDI≥15 eventsh -1. Subjective sleep quality, sleepiness, and sociodemographic characteristics were evaluated by questionnaires. Results: Increased sleep duration from actigraphy was associated with reduced odds of SDB (OR 0.44 per hour, p= 0.043). Neither subjective sleep quality nor sleepiness was associated with SDB. Male sex, older age, and increased waist circumference were associated with increased odds of SDB. Conclusions: In this sample of obese adults, subjective measures of sleep quality and sleepiness were not indicators of SDB. These results suggest that, in obese patients, physicians should not rely on subjective measures to determine who should be referred for a clinical sleep study. A wider use of portable apnea screening devices should be considered in nonsymptomatic, non-Hispanic white males. © 2012 Elsevier B.V.


Knutson K.L.,University of Chicago | Galli G.,Section on Neuroendocrinology of Obesity | Galli G.,University of Pisa | Zhao X.,Section on Neuroendocrinology of Obesity | And 2 more authors.
Obesity | Year: 2011

Previous research in lean subjects has found lower leptin levels associated with shorter sleep duration. Since leptin levels are higher and some of the actions of leptin are impaired in obese individuals, one cannot assume that sleep will be similarly associated with leptin in obese individuals. The aim of this paper was to examine the cross-sectional association between habitual sleep duration and quality and plasma leptin levels in a sample of 80 obese men and premenopausal women aged 18-50 years. Leptin levels (ng/ml) were assayed on a fasting blood sample taken in the morning. We calculated a relative leptin level by dividing leptin by body fat percentage. Sleep duration and sleep efficiency were measured by 2 weeks of wrist actigraphy and respiratory disturbance index (RDI), a measure of sleep disordered breathing, was assessed by a portable screening device on a single night. Mean leptin levels and body fat percentage were higher in women than men (P 0.001), however, mean RDI was higher in men (P = 0.01). There were no significant associations between relative leptin level and any of the sleep measures, including sleep duration, sleep efficiency, and sleep disordered breathing. There was also no difference between men and women in the association between sleep and leptin. In conclusion, contrary to what has been reported in other studies, measures of sleep duration and quality were not associated with leptin levels in our sample of obese adults. © 2011 The Obesity Society.


Cizza G.,Section on Neuroendocrinology of Obesity | Requena M.,Section on Neuroendocrinology of Obesity | Galli G.,Section on Neuroendocrinology of Obesity | Galli G.,University of Pisa | De Jonge L.,Section on Neuroendocrinology of Obesity
Journal of Endocrinological Investigation | Year: 2011

Sleep duration has progressively fallen over the last 100 years while obesity has increased in the past 30 years. Several studies have reported an association between chronic sleep deprivation and long-term weight gain. Increased energy intake due to sleep loss has been listed as the main mechanism. The consequences of chronic sleep deprivation on energy expenditure have not been fully explored. Sleep, body weight, mood and behavior are subjected to circannual changes. However, in our modern environment seasonal changes in light and ambient temperature are attenuated. Seasonality, defined as cyclic changes in mood and behavior, is a stable personality trait with a strong genetic component. We hypothesize that the attenuation in seasonal changes in the environment may produce negative consequences, especially in individuals more predisposed to seasonality, such as women. Seasonal affective disorder, a condition more common in women and characterized by depressed mood, hypersomnia, weight gain, and carbohydrate craving during the winter, represents an extreme example of seasonality. One of the postulated functions of sleep is energy preservation. Hibernation, a phenomenon characterized by decreased energy expenditure and changes in the state of arousal, may offer useful insight into the mechanisms behind energy preservation during sleep. The goals of this article are to: a) consider the contribution of changes in energy expenditure to the weight gain due to sleep loss; b) review the phenomena of seasonality, hibernation, and their neuroendocrine mechanisms as they relate to sleep, energy expenditure, and body weight regulation. ©2011, Editrice Kurtis.


PubMed | Section on Neuroendocrinology of Obesity
Type: Journal Article | Journal: Journal of endocrinological investigation | Year: 2012

Sleep duration has progressively fallen over the last 100 years while obesity has increased in the past 30 years. Several studies have reported an association between chronic sleep deprivation and long-term weight gain. Increased energy intake due to sleep loss has been listed as the main mechanism. The consequences of chronic sleep deprivation on energy expenditure have not been fully explored. Sleep, body weight, mood and behavior are subjected to circannual changes. However, in our modern environment seasonal changes in light and ambient temperature are attenuated. Seasonality, defined as cyclic changes in mood and behavior, is a stable personality trait with a strong genetic component. We hypothesize that the attenuation in seasonal changes in the environment may produce negative consequences, especially in individuals more predisposed to seasonality, such as women. Seasonal affective disorder, a condition more common in women and characterized by depressed mood, hypersomnia, weight gain, and carbohydrate craving during the winter, represents an extreme example of seasonality. One of the postulated functions of sleep is energy preservation. Hibernation, a phenomenon characterized by decreased energy expenditure and changes in the state of arousal, may offer useful insight into the mechanisms behind energy preservation during sleep. The goals of this article are to: a) consider the contribution of changes in energy expenditure to the weight gain due to sleep loss; b) review the phenomena of seasonality, hibernation, and their neuroendocrine mechanisms as they relate to sleep, energy expenditure, and body weight regulation.

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