Is night eating syndrome associated with obstructive sleep apnea, BMI, and depressed mood in patients from a sleep laboratory study?

PURPOSE

The aim of this study was to assess night eating syndrome (NES) in patients referred for polysomnography and its association with obstructive sleep apnea (OSA). We also assessed whether participants with OSA were more likely to get up and eat at night, and whether these behaviors were associated with the apnea-hypopnea sleep index (AHI). We additionally examined whether NES and OSA were associated with BMI, and assessed depressed mood among participants with NES or OSA.

METHODS

The Night Eating Diagnostic Questionnaire (NEDQ), Zung Depression Scale, and demographic and medical questionnaires were used to evaluate 84 qualified participants. Polysomnography was used to assess AHI, and therefore OSA.

RESULTS

Thirty individuals met full or sub-threshold NES (NES[St]) criteria, and 54 had no night eating (Normal). Eighty-nine percent of the sample had OSA with AHI≥5. Neither AHI nor BMI differed between NES(St) and Normal, F(1,82)=1.67, p=0.20 and F(1, 82)=2.2, p=0.14, respectively. Participants with NES(St) were, however, more likely than Normal to have depressed mood (mild, moderately, or severely depressed), χ=4.47 p=0.03. There was a positive correlation between AHI and BMI, r=0.37, p=0.001. Those with OSA were not more likely to eat at night, F(1,82)=0.04, p=0.84, or get out of bed more often, F(1,13)=0.23, p=0.64, and there was no correlation between AHI and eating at night (r=-0.11, p=0.31). However, there was a positive correlation between AHI and the number of times participants got up out of bed (r=0.81, p<0.001).

CONCLUSIONS

We found that NES was not associated with BMI or AHI severity. The findings show that NES is primarily an eating disorder, rather than a sleep disorder, and that there is an association between NES and depressed mood.