More links between sleep apnea and obesity

Baltimore, January 26: Further bolstering the connection between obesity and sleep apnea, researchers have established that three conditions, which are usually tied to obesity, also have independent links with sleep disordered breathing (SDB).

Insulindefine resistance, the development of liver disease, and a less active life are associated with the common breathing disorder without taking the person’s weight into consideration, reported the scientists in the February issue of the American Journal of Respiratory and Critical Care Medicine.

A research conducted at the John Hopkins University revealed insulin resistance, which renders the body unable to metabolize glucose, is directly linked to the sleep-disordered breathing (SDB).

"Our major finding was that, as we suspected, SDB was strongly associated with a decrease in the three major metabolic pathways that the body uses to metabolize glucose— insulin sensitivity, glucose effectiveness, and pancreatic cell function— independent of adiposity," said lead author Dr. Naresh Punjabi, an associate professor of medicine and epidemiology at Johns Hopkins University School of Medicine.

"What our research tells us is that SDB is characterized by multiple physiological deficits that increase the predisposition for type 2 diabetesdefine mellitus.”

In a separate study, the researchers found that the oxygen deficit caused by obstructive sleep apnea (OSA), led to liver problems, directly proportional to the severity of sleep disorder.

“The hypoxic stress of OSA may induce oxidative stress in the livers of patients with severe obesity, leading to further inflammation,'' said lead researcher Dr. Vsevolod Y. Polotsky, of the Johns Hopkins Asthma and Allergy Center.

Another factor common to obesity and sleep apnea is sedentary lifestyle. The reduced movement of calf muscles leads to accumulation of the fluid in legs.

“Sedentary living may predispose to OSA not only by promoting obesity, but also by causing dependent fluid accumulation in the legs, which can shift rostrally to the neck overnight," said Dr. T. Douglas Bradley, professor of medicine and director of the Centre for Sleep Medicine and Circadian Biology at the University of Toronto.

Despite these three conditions common to both, obesity and sleep apnea are not completely related and researchers insist that the disorders must be treated independently, in order to address any secondary complications arising from them.