Purpose of review This review summarizes the most recent evidence linking decreased sleep duration and poor sleep quality to obesity, focusing upon studies in adults. Recent findings Published and unpublished health examination surveys and epidemiological studies suggest that the worldwide prevalence of obesity has doubled since 1980. In 2008, 1 in 10 adults was obese, with women more likely to be obese than men. This obesity epidemic has been paralleled by a trend of reduced sleep duration. Poor sleep quality, which leads to overall sleep loss has also become a frequent complaint. Growing evidence from both laboratory and epidemiological studies points to short sleep duration and poor sleep quality as new risk factors for the development of obesity. Summary Sleep is an important modulator of neuroendocrine function and glucose metabolism and sleep loss has been shown to result in metabolic and endocrine alterations, including decreased glucose tolerance, decreased insulin sensitivity, increased evening concentrations of cortisol, increased levels of ghrelin, decreased levels of leptin, and increased hunger and appetite. Recent epidemiological and laboratory evidence confirm previous findings of an association between sleep loss and increased risk of obesity.

Background: Sleep exerts important modulatory effects on neuroendocrine function and glucose regulation. During the past few decades, sleep curtailment has become a very common behavior in industrialized countries. This trend toward shorter sleep times has occurred over the same time period as the dramatic increases in the prevalence of obesity and diabetes. Aims: This article will review rapidly accumulating laboratory and epidemiologic evidence indicating that chronic partial sleep loss could play a role in the current epidemics of obesity and diabetes. Conclusions: Laboratory studies in healthy young volunteers have shown that experimental sleep restriction is associated with a dysregulation of the neuroendocrine control of appetite consistent with increased hunger and with alterations in parameters of glucose tolerance suggestive of an increased risk of diabetes. Epidemiologic findings in both children and adults are consistent with the laboratory data.

OBJECTIVE To estimate whether metformin use by ovarian cancer patients with type II diabetes was associated with improved survival. METHODS We reviewed the effect of diabetes and diabetes medications on ovarian cancer treatment and outcomes in a single-institution retrospective cohort. Inclusion criteria were International Federation of Gynecology and Obstetrics (FIGO) stage I–IV epithelial ovarian, fallopian or peritoneal cancer. Exclusion criteria were noninvasive pathology or non-epithelial malignancies. The primary exposures analyzed were history of type II diabetes and diabetes medications. The primary outcomes were progression-free and overall ovarian cancer survival. RESULTS Of the 341 ovarian cancer patients included in the study, 297 did not have diabetes, 28 were type II diabetic patients who did not take metformin, and 16 were type II diabetic patients who used metformin. The progression-free survival at five years was 51% for diabetic patients who used metformin compared to 23% for the nondiabetic patients and 8% for the diabetic patients who did not use metformin (P=.03). The overall survival at 5 years was 63%, 37%, and 23% for the diabetic patients who used metformin, the nondiabetic patients, and the diabetic patients who did not use metformin, respectively (P=.03). The patients with diabetes received the same treatment for ovarian cancer as the patients without diabetes. The association of metformin use and increased progression-free survival, but not overall survival, remained significant after controlling for standard clinico-pathologic parameters. CONCLUSION In this ovarian cancer cohort, the patients with type II diabetes who used metformin had longer progression-free survival, despite receiving similar treatment for ovarian cancer.

Several lines of evidence indicate that chronic lack of sleep may contribute to the risk of type 2 diabetes mellitus. Adequate sleep and good sleep hygiene should be included among the goals of a healthy lifestyle, especially for patients with diabetes. We urge clinicians to recommend at least 7 hours of uninterrupted sleep per night as part of a healthy lifestyle.