The book Sleep Loss and Obesity: Intersecting Epidemics provides timely information on the two highly prevalent states in America and worldwide: obesity and sleeplessness. In their preface, the editors note the high prevalence of obesity worldwide and the relatively recent recognition that sleep, a previously overlooked behavior, is related to this obesity epidemic. The book is excellent at connecting the two epidemics and providing physiological explanations for this association.
The first two chapters provide a good overview of the molecular and genetic regulations of sleep and energy metabolism, setting the stage for subsequent chapters discussing the neural circuits involved in the control of sleep and eating behaviors. Chapter 3 discusses the neural controls of sleep and introduces concepts and neural centers that are further described in chapter 4 to explain the reward circuitry associated with food intake control. Hypocretins/orexins are described at length for their role in arousal and wakefulness. In chapter 4, the role of orexin in reward is introduced. This chapter goes in great depth to explain neural pathways of reward involved in feeding and closes by explaining the connection with sleep and sleep disturbances. Chapters 5 and 6 provide somewhat overlapping information and further elaborate on the brain's involvement in food intake control. In chapter 5, the coverage goes beyond neural circuits to include an in-depth description of neuroendocrine regulators, whereas chapter 6 provides additional information on genetic errors that lead to obesity. This last chapter is well written and easy to follow, but the discussion of obesity syndromes lack relatedness to sleep, particularly with regard to Prader-Willi Syndrome, ciliopathies, and Carpenter syndrome. These first 6 chapters could be considered as one overall section describing the neurohormonal circuitry involved in sleep and weight regulation.
The remaining eight chapters discuss various sleep-related health effects associated with obesity. For example, chapter 7, which is very well written, provides an overview of the sleep-obesity relationship in children. This chapter provides much epidemiological evidence, a clear difference in style from previous chapters which have shown more molecular data. Chapter 8 is an excellent chapter on circadian rhythms and obesity, which builds nicely on the early section on the neural bases of obesity. Obstructive sleep apnea (OSA) is introduced in chapter 9, which provides a good overview of the disorder, risk factors for its development, and its relationship with obesity. Chapter 10, the longest chapter in the book, provides an extensive and comprehensive review of the relationship between sleep duration and obesity and diabetes risk in adults. This chapter reviews the evidence for a putative mechanism of action by which short sleep duration could cause obesity and diabetes, as determined by clinical trials. It is logically organized and brings in information on the orexin system so well laid out in chapters 1-6. Chapter 11 further builds on this chapter by going into the relationship between sleep and sleep disorders and diabetes. Issues of residual confounding in research and potential sex differences in the association between sleep and obesity/diabetes are raised in chapter 12. Chapter 13 provides an excellent overview of OSA and clinical indications for its evaluation and treatment. Because this chapter does such a good job at defining and explaining OSA, the reader would have benefited from this information earlier in the book, potentially alongside chapter 9.
Finally, chapters 14-15 provide information on weight loss treatments. In chapter 14, a wide array of dietary and drug options for weight loss are discussed. This chapter provides a very interesting historical perspective of pharmacological weight loss treatments and describes various classes of drugs as well as dietary supplements. This is an excellent chapter. However, as with several other chapters, some ties to sleep would have been good to highlight. For example, the link between sleep-related adverse effects of some drugs could have been highlighted to be related to the neurocircuitry of sleep so eloquently illustrated in chapter 3. Metabolic and bariatric surgery as a treatment for weight loss and its effects on OSA are presented in chapter 15.
Overall, this is a very complete book discussing the relationship between sleep and obesity that goes beyond just those two topics to include sleep and obesity-related disorders. The reader will find a very extensive and complete section on neuronal regulation of sleep and appetite but also very clinical information on OSA and weight loss treatments.
CITATION
St-Onge MP. Sleep Loss and Obesity: Intersecting Epidemics. SLEEP 2014;37(1):209.
DISCLOSURE STATEMENT
Dr. St-Onge has indicated no financial conflicts of interest.