HEALTH NEWS

Study Title:

Sleep Apnea, Diet, and Exercise

Study Abstract

The purpose of this study was to examine whether dietary habits and physical activity patterns were independently associated with severity of sleep disordered breathing (SDB) in adults diagnosed with obstructive sleep apnea. Data collected from 320 adults participating in an ancillary study of The Apnea Positive Pressure Long-term Efficacy Study were analyzed as a cross-sectional assessment at study baseline. The respiratory disturbance index (RDI) was used as a measure of the severity of sleep disordered breathing. Separate linear regression models were fitted using RDI as the independent variable and various preselected components of dietary intake and physical activity as the dependent variables. The results indicated that even after adjusting for BMI, age, and daytime sleepiness, subjects with very severe and extremely severe SDB (RDI ≥ 50) consumed a diet that was higher in cholesterol, protein, total fat, and total saturated fatty acids. These findings were most evident among women. For all participants, those with RDI ≥ 50 in comparison to those < 50, on average consumed 88.16 more mg of cholesterol per day (95% CI: 44.45 to 131.86, p < 0.001). Among the women participants only, those with RDI ≥ 50 in comparison to those < 50, on average consumed 21.96 more grams of protein (95% CI: 2.64 to 41.29, p = 0.026), 27.75 more grams of total fat (95% CI: 3.38 to 52.11, p = 0.026), and 9.24 more grams of saturated fatty acids (95% CI: 0.67 to 17.80, p = 0.035). Furthermore, those with an RDI ≥ 50 had a 224.58 greater caloric expenditure than those with RDI < 50 from all activities including work and sleep (95% CI: 40.98 to 408.18, p = 0.017). Although significant results were seen in a reduction of physical activity from recreational activities, this finding was explained by the increase in BMI associated with higher levels of RDI.

From press release:

A new study shows that unrelated to obesity, people with severe SDBs consume a more unhealthy diet, which may be a factor contributing to greater cardiovascular morbidity and mortality. These findings were most evident among women.

Stuart Quan, MD, division of sleep medicine at Harvard Medical School, said, "We found that persons who had severe obstructive sleep apnea ate a diet that was unhealthy with increased intake of cholesterol, fat and saturated fatty acids."

Findings showed that, on average, all participants with extremely severe SDB, or those with respiratory disturbance index (RDI) above 50 disruptions per hour, consumed 88.16 more milligrams of cholesterol per day compared to people who have less severe OSA. On average, women participants with severe SDB consumed 21.96 more grams of protein, 27.75 more grams of total fat and 9.24 more grams of saturated fatty acids. These results remained significant after controlling for BMI, age and daytime sleepiness.

Results indicated that among the 320 participants, increasing RDI severity was associated with greater consumption of cholesterol, protein and trans-fatty acids. There also was a trend towards greater ingestion of total saturated fatty acids and total fat, but not carbohydrates, sucrose or dietary fiber. With the exception of cholesterol, these associations occurred primarily in women. The mechanism producing the higher dietary consumption of unhealthy nutrients in persons with extremely severe SDB appears to exaggerate behaviors already observed among obese women.

Compared with the 2005 U.S. Dietary Guidelines, participants "ate less than the recommended proportion of calories from carbohydrate and more than recommended from total and saturated fat."

It is unlikely that sleep deprivation or obesity explain the results of the study. It has been suggested that fatigue and sleepiness, as well as sleep deprivation influence dietary intake via alterations in neuroendocrine control of feeding behavior; however, controlling for Epworth Sleepiness Scale score did little to affect our results and in bivariate analysis, total sleep time was not associated with alterations in dietary intake.

According to Quan, the physical activities findings in the study were unexpected. "All of us suspect that patients with sleep apnea engage in less recreational activity. This was confirmed in the study," said Quan. "However, the findings were explained entirely by obesity. We thought that because sleep apnea patients are sleepy they would engage in less physical activity even after accounting for the effect of obesity."

It is well known that obese people are more likely to consume diets high in fat and cholesterol. The persistence of these results even after controlling for BMI suggests that a high RDI has an independent effect on dietary intake. Researchers of this study suggest that independent of sleep duration, OSA may affect levels of appetite-regulating hormones. Also, sleep disruptions related to OSA may in some way increase the craving for fatty foods.

Obstructive sleep apnea, (OSA), which is a form of SDB is characterized by repetitive episodes of complete or partial airway obstruction during sleep is currently estimated to affect 18 million Americans. OSA is associated with alterations in leptin and ghrelin, which are important in appetite regulation. It has been demonstrated that sleep deprivation, a common occurrence among people with OSA, is associated with increased body max index (BMI) and increased cravings for carbohydrates. The change in hormones results in leaves that may increase appetite and thus impact dietary intake.

To investigate the relationships between dietary intake, physical activity, OSA, sleep and obesity, the study used data from a subset of the Apnea Positive Pressure Long-Term Efficacy Study (APPLES), a randomized, double-blinded, two-arm, sham-controlled, multicenter, six-month, intent-to-treat study of continuous positive airway (CPAP) efficacy on neurocognitive function in OSA.

The study included 320 participants – 263 from the University of Tucson in Arizona and 57 from the St. Mary Medical Center in Walla Walla, Washington. More than half of the participants were obese. In addition to receiving polysomnography (PSG) studies and neurocognitive assessment, participants were asked to complete detailed dietary and physical activity questionnaires prior to the initial diagnostic PSG and at the end of the four-month clinical APPLES examinations.

Poor sleep quality, a consequence of OSA, is associated with fatigue and sleepiness, which may curtail physical activity; low sleep quality may also result in a compensatory increase in caloric intake in an effort to boost energy levels, both of which promote weight gain. This study provides important new information on the dietary habits of people with OSA, which may be another mechanism through which SDB leads to serious health conditions such as cardiovascular disease, hypertension and stroke. Based on the study's findings, unhealthy dietary and activity patterns warrant further study of their role in cardiovascular and metabolic syndrome development in patients with OSA.

Study Information

Monica M. Vasquez, James L. Goodwin, Amy A. Drescher, Terry W. Smith, and Stuart F. Quan.
Associations of Dietary Intake and Physical Activity with Sleep Disordered Breathing in the Apnea Positive Pressure Long-term Efficacy Study (APPLES).
Journal of Clinical Sleep
2008 October
Sleep and Arizona Respiratory Centers, University of Arizona College of Medicine, Tucson, AZ.