On the Relationship between Diabetes and Obstructive Sleep Apnea: Evolution and Epigenetics

Abstract

This review offers an overview of the relationship between diabetes, obstructive sleep apnea (OSA), obesity, and heart disease. It then addresses evidence that the traditional understanding of this relationship is incomplete or misleading. In the process, there is a brief discussion of the evolutionary rationale for the development and retention of OSA in light of blood sugar dysregulation, as an adaptive mechanism in response to environmental stressors, followed by a brief overview of the general concepts of epigenetics. Finally, this paper presents the results of a literature search on the epigenetic marks and changes in gene expression found in OSA and diabetes. (While some of these marks will also correlate with obesity and heart disease, that is beyond the scope of this project). We conclude with an exploration of alternative explanations for the etiology of these interlinking diseases.

Keywords: OSA; diabetes; epigenetics; evolution; obstructive sleep apnea.

Figure 1

Models of the cause of lifestyle diseases: (A) a traditional model posits obesity as the lynchpin of lifestyle disease. If lifestyle diseases (diabetes, obstructive sleep apnea, etc.) are caused by obesity, and obesity is caused by eating too much and not exercising enough, the cure is simple and obvious. Unfortunately, human health and lifestyle diseases are generally much more complex than this model suggests; (B) an alternative model of lifestyle diseases. This model suggests that many factors interact to trigger a disease state in susceptible individuals, with obesity being a consequence of a combination of influences. Increased body mass index may be protective against the effects of many harmful factors, helping to delay or prevent negative health outcomes until a critical threshold has been reached where ongoing harmful inputs override protective benefits.