Background Studies have found inconsistent correlations of sleep duration and sleep quality with non-alcoholic fatty liver disease (NAFLD), and there is no conclusion on this issue yet. Nurses are an occupational group with high incidences of sleep disorders and NAFLD.
Objective This study examines the associations of sleep duration and quality with NAFLD in nurses.
Methods A total of 2 671 nursing staff who participated in occupational physical examination in the spring of 2019 from a tertiary level-A hospital in Liaoning Province were selected as study subjects. According to the Guidelines for the Prevention and Treatment of Nonalcoholic Fatty Liver Diseases 2018, the nurses diagnosed with NAFLD were classified as case group, and those not as control group. A general information questionnaire and the Pittsburgh Sleep Quality Index Scale (PSQI) were used to investigate the basic information and sleep status of the participants. They were subgrouped according to the total PSQI score (very good, fairly good, fairly bad, and very bad) and sleep duration (≥ 7 h, 6-6.9 h, 5-5.9 h, and < 5 h). Statistical analysis was conducted using SPSS 24.0 software, and the associations of sleep duration and sleep quality with NAFLD in selected nurses were evaluated by binary logistic regression analysis.
Results A total of 2 584 nursing staff completed the questionnaires, with a valid return rate of 96.74%. There were 435 NAFLD cases (case group, 16.8%) and 2 149 healthy ones (control group); 17.7% of the nurses showed fairly bad and very bad sleep quality; 33.9% and 17.7% of the nurses slept 6-6.9 h and < 6 h respectively. The univariate analysis results found that there was no significant difference in the prevalence of NAFLD among the nurses with different sleep qualities (P=0.058), but the prevalence was different among the nurses with different sleep durations (P < 0.001). After adjusting for age, gender, job title, department, frequency of night shifts, systolic blood pressure, diastolic blood pressure, body mass index, fasting blood glucose, triglycerides, high-density lipoprotein, low-density lipoprotein, and total cholesterol, sleep duration < 6 h was significantly associated with NAFLD (5-5.9 h sleep duration group, OR=1.562, 95% CI:1.081-2.259, P=0.018; < 5 h sleep duration group, OR=2.075, 95% CI:1.161-3.709, P=0.014).
Conclusion The nurses sleeping < 6 h a day have a higher prevalence of NAFLD than those sleeping more.
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