Obesity, Sleep Apnea and Cognitive Functions in Children - Research Paper Example

Obstructive sleep apnea is caused when the airways are significantly narrowed, and again increased neck weight can contribute to this narrowing and the subsequent breathing problems (Chan et al, 2004). Although the links between sleep apnea and obesity are well-researched, the links between impaired cognitive function, obesity and sleep disruption are minimal, although studies have been done comparing two of the above. The article in question (Clark, 2005) illustrates the possible links found between all three of the conditions.

The purpose of this paper is to examine the biology behind the research and investigate the possible reasons for the connection. The structure of the pharynx is illustrated in figure 1. From this diagram, it is evident that the windpipe is a narrow structure and any further narrowing could cause a lowered ability to receive sufficient air into the lungs. Obstructive sleep apnea is categorized by a cyclic closing and opening of the pharynx during sleep, which can lead to disrupted gas exchange and disturbed sleep (Strohl, 1996).

Evidently, any disruption in sleep is going to cause excessive fatigue/sleepiness, but research suggests that the effects of sleep apnea go beyond this and cause behavioural problems (such as impulse control and hyperactivity) and cognitive deficits. It has been suggested that these are caused by intermittent states of hypoxemia as well as reductions in brain metabolism (Clark, 2005). Figure 1 – Diagram of the neck illustrating the pharynx (Clark, 2005) There are also suggestions that obesity is linked to cognitive deficits.

Learning, memory and abstract reasoning were all shown to be lower in people suffering from obesity and hypertension, although the effects were seen in men only (Elias et al, 2003). Despite this evidence, it is unclear whether obesity is a result of or a cause of these impaired cognitive facilities. People who have taken part in cognitive skill building exercises as younger children are shown to have less chance of developing obesity as adults (Hill et al, 2003), but this could be partly due to socioeconomic factors.

Other suggestions have been made that show that impaired cognitive function is a result of obesity. The glucocorticoids (GC), for example, are implicated. Figure 2 shows the chemical structure of cortisol, an important example in this group of steroid hormones. GCs are found in almost every vertebrate cell, and bind to the glucocorticoid receptor (GR). GCs are important in several areas of the brain, including the hippocampus, the amygdala and the frontal lobes (Clark, 2005). In obesity, individuals may be exposed to an abnormally high amount of glucocorticoids (Masuzaki et al, 2001), and evidently if they play an important role in brain function, obesity could well be a cause of impaired cognitive function.

Image 2 – The Chemical Structure of Cortisol (Clark, 2005) Obesity has also been linked to a number of neurological conditions, primarily stroke. A stroke is characterized by a swift loss of brain function because of a blockage or other disturbance of the blood supply to the brain (Clark, 2005). Thrombotic stroke is the most common type of stroke in obese individuals (Clark, 2005). Blood supply in