IL6 and neurodegenerative disease: Notably, daytime napping or daytime sleepiness has been associated with the occurrence of degenerative diseases such as Parkinson's disease and dementia in the older population.38, 39 It has also been reported that chronic inflammation, as indicated by an elevation in plasma interleukin 6 levels, was predictive of future Parkinson's disease.40 In the current study, daytime napping was associated with a higher serum CRP level, while information on other inflammatory biomarkers was not obtained.