Selected baseline characteristics of NHANES 2005–06 participants by sleep duration categories (n = 2,459)1,2.

Abbreviations: 25(OH)D = 25-hydroxyvitamin D; n-3 HUFA = n-3 highly unsaturated fatty acids; NHANES = National Health and Nutrition Examination Survey; SE = Standard error; tHcy = Total homocysteine.1Values are mean±SE or percent±SE. Sampling design complexity is taken into account in all analyses. This analysis is done among participants with complete data for sleep quality variables and other key variables of interest (n = 2,459).2P-value was based on design-based F-test if row variable is categorical and t-test if row variable is continuous (comparing normal sleep to each of the other categories).3P4P