By Liza Baskin
People with sleep apnea experience pauses in their breathing or shallow breaths while they sleep. In adults, the condition has been linked to diabetes and heart disease, but that link is less clear in younger people with sleep apnea.
In a recent study, researchers found that obstructive sleep apnea (OSA) was linked with greater cardiometabolic risk markers in obese youth. Cardiometabolic risk markers are signs of a patient's overall risk for type 2 diabetes and heart disease.
The findings also showed that teenage boys had a higher risk of having OSA than teenage girls.
The authors believe this relationship needs to be considered when undergoing evaluation for OSA. They also believe further research is needed on OSA and its association with cardiometabolic risk markers — especially for young men.
This study was conducted through the Indiana University School of Medicine in Indianapolis, Indiana. The lead author was S. E. Watson, MD, from the section of Pediatric Endocrinology and Diabetology in the Department of Pediatrics.
Participant data was pulled from medical records of patients who were part of the Pediatric Overweight Education and Research (POWER) Program between January 2009 and November 2011.
The researchers assessed 96 adolescents, between the ages of 12 and 16, who were obese and referred for polysomnography (PSG; sleep study that measures brain waves, oxygen level in the blood, heart rate, breathing and leg and arm movements) during the POWER program.
In order to have been referred for PSG, there had to be either parental concern or complaints of "...snoring accompanied by excessive daytime sleepiness, morning headache and/or behavioral problems suspected to be related to sleep disruption." Patient medical history was obtained at the first visit, and the patients were tested for levels of fat cells in blood, liver enzymes, glucose and insulin.
The participants underwent overnight PSG in order to calculate their apnea-hypopnea (disorder which involves overly shallow breathing or an abnormally low respiratory rate) index, or AHI. The AHI is determined by adding the total number of OSA and hypopnea events during an hour of sleep.
The researchers then put the participants in two groups: 1) the participants with AHI scores of less than five, indicating mild or no OSA, and 2) the participants with of five or more, indicating moderate or severe OSA. Eighty of the participants had mild or no OSA, and 16 of the participants had moderate or severe OSA.
Significantly more teen boys (11) were found to have moderate or severe OSA than teen girls (5), despite similar levels of obesity. Hispanic males were especially affected, with two out of five having moderate or severe OSA.
The researchers also found that there was lower insulin sensitivity — or higher insulin resistance — in the moderate and severe cases of OSA, compared to the participants with mild or no OSA. Insulin is a hormone that the body produces to help manage levels of blood sugar. If someone has a lower insulin senstivity, the body can't use the insulin properly, which puts them at risk for high blood sugar and type 2 diabetes.
The participants with moderate or severe OSA were also found to have a higher levels of fat in their blood than the other participants.
Ultimately, there was a low percentage of participants with OSA in the study sample; therefore the researchers maintained that the OSA-related symptoms of daytime drowsiness and snoring were not reliable indicators of OSA.
The researchers see a need for further research on potential race/ethnicity determinants of OSA and the associated cardiometabolic risk factors in youth — especially in young men.
The authors mentioned a few limitations of their study.
First, there was a small number of Hispanic participants, so the findings on Hispanic men could be over- or underestimated.
Second, the researchers could not draw conclusions about the underlying pathways for the relationship between cardiometabolic risk factors and the degree of OSA because of the retrospective and clinical nature of the participant data.
Third, there were no uniform measures of the risk factors the participants were tested for—only comparisons within the study group. Lastly, the study population consisted of patients who had specifically been referred for OSA testing, so the researchers argue that the study results cannot be applied to the general pediatric population without further study.
This study was published online ahead-of-print in the September edition of Pediatric Obesity.
Indiana University-Purdue University, the National Institutes of Health, and the Regenstrief Institute provided funding.