Diabetes, Polycystic Ovarian Syndrome, Obstructive Sleep Apnea, and Obesity: A Systematic Review and Important Emerging Themes.

Type 2 diabetes mellitus (DM), polycystic ovarian syndrome (PCOS), obstructive sleep apnea (OSA), and obesity represent four large and growing patient populations. A great deal of scientific and clinical knowledge has been developed for them individually, and significant advancements made. Taken as a group, however, the interrelationships are not as well understood. The purpose of this systematic review is to identify the body of existing research that ties them together and then to identify and discuss the prevailing themes, particularly for cause-and-effect mechanisms. PubMed, Google Scholar, and ScienceDirect were used to identify systematic reviews and meta-analysis articles to establish the broadest reach. Initially, 434 articles were carefully screened, out of which 22 most relevant studies were reviewed. Five important themes were distilled from these papers based on continued and consistent emphasis in the literature. These themes include topics such as the importance of considering visceral obesity rather than Body Mass Index (BMI), the most effective treatment approaches, including mounting support for melatonin and circadian rhythm management, the results of OSA in its feed-forward contribution to hormone imbalance, the role of non-obesity-related risk factors to PCOS and OSA such as age and genetic predisposition, and growing evidence to suggest the importance of mental health as a comorbidity in addition to the more traditional ones such as cardiovascular pathology. A new framework for investigating the interaction across these four disorders is offered that includes a revised perspective on the specific role of PCOS, perhaps being further upstream relative to the others. There currently exists a lack of well-designed randomized controlled trials in this particular area of medicine, an endeavor we believe could result in significant value, particularly as it relates to treatment approaches.