A study in the October 15 issue of the Journal of Clinical Sleep Medicine 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.