Population characteristics according to habitual day napping.

Data are expressed as median (interquartile range, 25%–75%) for continuous variables and proportions for categorical variables. BMI, body mass index; WHR, waist hip ratio; SBP, systolic blood pressure; DBP, diastolic blood pressure; Cr, creatinine; GPT, glutamic-pyruvic transaminase; AST, aspartate aminotransferase; GGT, gamma-glutamyl transpeptidase; FPG, fasting plasma glucose; 2 hPG, 2 h postchallenge plasma glucose; FINS, fasting serum insulin; HOMA-IR, Homeostasis Model Assessment for insulin resistance; TC, total cholesterol; TG, triglyceride; HDL-c, high-density lipoprotein-cholesterol; LDL-c, low-density lipoprotein-cholesterol. *P<0.05 compared with non-nappers. †N = 6438.