Association between bedtime at night and nonalcoholic fatty liver disease diagnosed by liver ultrasound transient elastography

We aimed to explore the association between bedtime at night and nonalcoholic fatty liver disease (NAFLD) measured by liver ultrasound transient elastography (LUTE).A total of 4572 individuals were included. The diagnosis of NAFLD was based on the controlled attenuated parameter (CAP) score of LUTE. CAP score ≥ 263 dB/m and CAP score ≥ 285 dB/m were used as the criterions for the diagnosis of NAFLD.For the weekday bedtime, a positive association was identified in CAP (263 dB/m) (OR, 1.04 [95 %CI, 0.99, 1.09]) and CAP (285 dB/m) (OR, 1.00 [95 %CI, 0.95, 1.05]). For the weekend bedtime, a positive relationship was found in CAP (263 dB/m) (OR, 1.05 [95 %CI, 1.00, 1.10]). The positive relationship still presented in CAP (285 dB/m) (OR, 1.05[95 %CI, 1.00, 1.10]). When NAFLD defined as CAP score ≥ 263 dB/m, the relationship between weekday bedtime and NAFLD was a straight line. For the weekend bedtime, the association was nonlinear. Before 22:00 o'clock, the association was positive (OR, 1.26 [95 %CI, 1.06, 1.50]), while between 22:00 and 1:00 o'clock, the relationship was negative (OR, 0.96 [95 %CI, 0.88, 1.05]) without a significant P value. After 1:00o'clock, the relationship was positive (OR, 1.26 [95 %CI, 1.02, 1.57]).Later bedtime was positive associated with NAFLD.