BOSTON, June 27 /PRNewswire/ -- Couch potatoes -- famous for inactivity and frequent snacking -- gain weight. Throw in the voluntary sleep curtailment that is becoming a more common feature of Western lifestyles, and you have the perfect prescription for increased insulin resistance. This is the conclusion of one of several studies on obesity, insulin resistance and diabetes that are being discussed at a media roundtable on Tuesday, June 27th at 11:00 A.M. EDT at ENDO 2006, the 88th Annual Meeting of The Endocrine Society to be held at the Boston Convention & Exhibition Center.
These new studies shed light on the links between lifestyle choices and diseases that arise from obesity: insulin resistance, diabetes, the Metabolic Syndrome and non-alcoholic fatty liver disease.
Combination of Western Lifestyle with Sleep Restriction Leads to Insulin Resistance
Dr. Plamen Penev of the University of Chicago wanted to find evidence that shortened sleep can lead to reduced insulin sensitivity, which in the long-term may result in increased risk of cardiovascular and metabolic disorders, such as coronary artery disease and diabetes. Four men and two women cycled through two different two-week tests. In one, the subjects were limited to sedentary indoor activity, given access to "palatable" food and were allowed to sleep for eight-and-a-half hours per night. In the second, they were limited to five-and-a-half hours of sleep each night.
Measurements of body weight and fat composition, as well as glucose tolerance, were taken before and after each test cycle. An index of insulin sensitivity was derived from the data. The outcome showed that reducing sleep worsened the impact of being a couch potato on insulin sensitivity.
"Our preliminary results indicate that body weight is compromised and weight goes up when people are exposed to an environment with unlimited availability of palatable food and low levels of daily activity," said Penev. "When sleep is restricted in this type of setting, there is a greater reduction in insulin sensitivity, which may increase the long-term risk of cardiovascular disease and diabetes."
Vitamin D Deficiency Associated with Metabolic Syndrome in Morbidly Obese Patients
In the past, vitamin D deficiency has been linked to Type 2 diabetes and cardiovascular risk. Dr. Jose Botella-Carretero of the Hospital Ramon y Cajal in Madrid, Spain, set out to show that vitamin D deficiency in morbidly obese patients is associated with insulin resistance and the Metabolic Syndrome (a cluster of conditions that includes high blood pressure, elevated insulin levels, excess body fat and high cholesterol levels).
The study looked at 73 morbidly obese patients and compared their body condition profiles with vitamin D concentrations. Of the 73, more than half had vitamin D deficiency and almost two-thirds had the symptoms associated with the Metabolic Syndrome. Of those with the Metabolic Syndrome, almost 61 percent had vitamin D deficiency.
"Our study shows that vitamin D deficiency is associated with the Metabolic Syndrome in morbidly obese patients," said Botella-Carretero. "This gives us yet more insight into conditions that should be addressed when dealing with obesity and insulin resistance."
Prevalence of Non-alcoholic Steatohepatitis in Patients with Type 2 Diabetes
Dr. Prashanth Mappa, with Seth GS MC and King Edward VII Memorial Hospital in Mumbai, India, focused on the prevalence of liver disease (steatohepatitis) in patients with Type 2 diabetes and attempted to correlate the disease with the Metabolic Syndrome.
The study began with 204 patients between the ages of 20-70 with Type 2 diabetes. After screening for liver disease and receiving consent for a liver biopsy, the study narrowed to 83 patients, 72.3 percent of whom had the Metabolic Syndrome. Almost 14 percent had normal livers, while almost 24 percent showed the beginning signs of fatty liver. More than half had varying degrees of marked liver disease.
"Patients with Type 2 diabetes had fatty infiltration of the liver more than half the time," said Mappa. "However, the presence or severity of liver disease did not correlate with any component of the Metabolic Syndrome."
Founded in 1916, The Endocrine Society is the world's oldest, largest, and most active organization devoted to research on hormones, and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 12,000 scientists, physicians, educators, nurses and students in more than 80 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society, and the field of endocrinology, visit our web site at http://www.endo-society.org.
Source: The Endocrine Society