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Coming this month in the Journal of Clinical Endocrinology & Metabolism JCE&M) Endocrinology: Obesity has long been considered a risk factor for cardiovascular disease (CVD) - the more overweight/obese an individual is, the more likely he or she is to be at risk. The relationship between abdominal fat, and specifically visceral fat, and disease risk is well-established, however, it is unclear whether lower-body fat stores also play a role in determining CVD risk. So, the higher prevalence of CVD in men, as compared to women, has been assumed to be due, in part, to the fact that men tend to accumulate fat in their abdominal regions, whereas women tend to store fat in their gluteal-femoral regions - their hips and thighs - at least before menopause. In the study, "Lower-Body Adiposity and Metabolic Protection in Postmenopausal Women," researchers from the University of Colorado at Denver aimed to determine whether a previous finding - that leg fat had favorable associations with risk factors for CVD in postmenopausal women after controlling for the harmful effects of trunk fat - persists when controlling instead for the effects of abdominal (either visceral or subcutaneous) fat. The researchers assumed that the strength of the favorable associations of leg fat with CVD risk factors, which were found after controlling for trunk fat, would be diminished when controlling for visceral adiposity. Their study evaluated 95 postmenopausal women (mean age, 60 ± 8 yr) by measuring whole body and regional fat distribution using dualenergy x-ray absorptiometry and abdominal computed tomography. Markers of insulin resistance and dyslipidemia were also determined using oral glucose tolerance tests (OGTT) and fasted lipid and lipoprotein measurements, respectively. All in all, findings from this study confirm that when a woman's fat mass is centralized in her lower-body, specifically her legs, she has a lower risk for CVD. It was further determined that if the presence of fat in a woman's legs is cardioprotective, then selective reduction of fat from this region (i.e., through lipectomy, liposuction) could adversely affect the woman's CVD risk. In this study, researchers note that after adjusting for abdominal visceral and/or subcutaneous fat, the cardioprotective benefit associated with leg fat was nullified. This study confirms the negative or harmful association between abdominal adiposity and CVD risk. These findings support the need for further research into the relationships between the centralization of fat mass in a patient's body and risk for CVD. Researchers Urge for Additional Screening, Standard Diagnoses to Lower Overall Economic Burden The polycystic ovary syndrome (PCOS) - characterized by irregular menstrual cycles, infertility, ovarian cysts, increased risk for diabetes and obesity, and excessive hair growth (hirsutism), among other health problems - is the most common endocrine-related condition of reproductive-aged women, affecting nearly 4 million women in the U.S. alone. The condition potentially represents a significant financial burden to our nation's healthcare system. Researchers, with the support of grants from Cedars Sinai Health System and the National Institutes of Health, conducted a systematic review of published medical literature to identify studies that evaluated the epidemiology of PCOS, as well as its clinical consequences and related costs. Results, as published in the study "Healthcare-Related Economic Burden of the Polycystic Ovary Syndrome During the Reproductive Lifespan," revealed the total healthcare-related economic costs associated with the condition amount to a remarkable $4.36 billion. Specifically:
The mean annual cost of the initial evaluation of PCOS was found to be just $93 million (2.1 percent of total costs), only a slight portion of the total economic burden associated with the condition. The true cost of PCOS may well exceed 4.5 billion since we did not consider the cost of treating the long-term morbidity of the disorder (e.g. type 2 DM) in the post-reproductive years. The researchers therefore concluded that more widespread and liberal screening for PCOS is the most cost-effective strategy to minimize the overall economic burden associated with this condition, as it would likely lead to earlier diagnosis and intervention. Translating Research Into Practice:
Level of Circulating Hormone Associated with Lower Cardiovascular Risk in Diabetic Women Adiponectin is a hormone thought to play an important role in regulating factors associated with atherosclerosis such as glycemia (the presence of glucose in the blood), lipidemia (the presence of excess lipids in the blood), endothelial dysfunction and proinflammatory mechanisms. Low levels of circulating adiponectin are associated with obesity, as well as with hyperlipidemia and insulin resistance. In addition, low levels of adiponectin have been shown to be a predictor of type 2 diabetes and of cardiovascular events in diabetic patients. Previous studies, however, have not yet fully evaluated the potential associations between adiponectin levels and circulating inflammatory markers and/or lipoprotein abnormalities among diabetic women. Whether or not (and in what way) lifestyle factors, anthropometric measures (determinants of a patient's body shape and size), and glycemia play a role in this relationship is also unknown. In the context of the Nurses' Health Study (NHS) - a study that is among the largest prospective investigations into the risk factors for major chronic diseases in women - researchers examined potential associations between circulating adiponectin levels, blood lipid and lipoprotein levels, as well as several inflammatory markers in a study population of 925 diabetic women. The findings, as published in the study "Circulating Adiponectin Levels Are Associated with Better Glycemic Control, More Favorable Lipid Profile, and Reduced Inflammation in Women with Type 2 Diabetes," reveal that circulating adiponectin levels were significantly and positively associated with high-density lipoprotein (HDL, or "good") cholesterol and physical activity levels, and inversely associated with body mass index and plasma concentrations of markers that typically signify inflammation. Of particular note, with the exception of the associations with triglycerides and apolipoprotein B100 (a specific protein/lipid combination that is a constituent of LDL, or "bad" cholesterol), which were significant only in subjects with body mass index readings less than 30, all other associations observed in this study were the same among both obese and nonobese diabetic women. Overall, the researchers conclude that higher adiponectin levels are associated with better glycemic control, more favorable lipid profiles and reduced inflammation in diabetic women. Researchers encourage additional study into the ways in which lifestyle modifications and medications designed to increase adiponectin levels may improve cardiovascular risk profiles and decrease cardiovascular morbidity and mortality among women with type 2 diabetes. It has been reported that excessive daytime sleepiness (EDS), the primary complaint of patients seen in sleep clinics, affects up to 12 percent of the general population and is commonly considered a sign of sleep apnea. Yet, the mechanism underlying the association between EDS and sleep apnea remains unclear. A team led by researchers at the Sleep Research and Treatment Center in the Department of Psychiatry at Penn State University College of Medicine assessed the association between the complaint of EDS and sleep apnea considering a wide range of possible risk factors in the study "Excessive Daytime Sleepiness in a General Population Sample: The Role of Sleep Apnea, Age, Obesity, Diabetes and Depression." The study population consisted of 16,583 men and women from Central Pennsylvania, ranging in age from 20 to 100 years. A random subset of this cohort (1,741 participants) was further evaluated for one night in a sleep laboratory setting. The study found that depression was the most significant risk factor associated with EDS, not sleep apnea. Further, a person's body mass index, age, typical sleep duration, the presence of diabetes and smoking habits all surpassed sleep apnea in strength of association with EDS. Interestingly, the older a person was, the less likely it was to see a relationship between their age and EDS, whereas the association of depression with EDS was stronger in the young. EDS was found to appear more often in trial participants younger than 30 years, suggesting the presence of unmet sleep needs and depression, and in participants older than 75 years, suggesting increasing medical illness and health problems. The researchers conclude that when diagnosing and treating a patient who complains of EDS, sleep apnea should not be the only cause considered. Rather, patients should be thoroughly assessed for depression, as well as obesity and diabetes, to rule out other causes that may impact one's sleepiness. After a full assessment of the patient's health, an appropriate treatment regimen can be implemented. |
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If you have any questions about this issue of The Endocrine Edge or The Endocrine Society, please contact Tadu Yimam at 301-941-0255 or via e-mail at tyimam@endo-society.org or tyimam@endo-society.org.