BACKGROUND: Internal migrant workers in the service industry are an important population in China, but the sleep quality of this population has not been well studied. The aims of the present study were to examine the prevalence of poor sleep quality among internal migrant workers in the service industry, explore the risk factors associated with poor sleep quality, and assess the correlation between insomnia and psychiatric factors.
METHODS: We conducted a cross-sectional study in Shenzhen, a migrant city in China. The respondent-driven sampling (RDS) method was used to recruit participants. Sociodemographic data and physical and psychiatric health status were investigated using questionnaires. In total, 1756 internal migrant workers completed the questionnaires. The Chinese version of the Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality, the General Anxiety Disorder-7 (GAD-7) and Center for Epidemiologic Studies Depression (CES-D) scales were used to assess anxiety and depression, respectively. Mental resilience was assessed by the Chinese version of the Connor-Davidson Resilience Scale (CD-RISC). Regression analysis was used to identify the risk factors of poor sleep quality. A structural equation model (SEM) was used to analyze the relationships among sleep, anxiety, depression and resilience.
RESULTS: The prevalence of poor sleep quality among internal migrant workers in the service industry was 25.4%. Multivariate regression analysis revealed that participants who were older (OR = 1.452), worked >8 h per day (OR = 1.553), had experienced physical illness in the past 2 weeks (OR = 3.631) and had psychiatric problems such as anxiety (OR = 1.695-3.331) and depression (OR = 1.437) had an increased risk of poor sleep quality (P < 0.05). Moreover, the risk of poor sleep quality increased as the severity of anxiety increased. We also detected sex-specific risk factors and depression associated with sleep quality in women (OR = 1.480, P < 0.05) but not in men. The SEM showed that sleep was mutually correlated with anxiety (r = 0.277, P < 0.001), depression (r = 0.301, P < 0.001), and resilience (r = -0.103, P < 0.001). Resilience was mutually correlated with anxiety (r = -0.179, P < 0.001) and depression (r = -0.222, P < 0.001).
CONCLUSIONS: Our study indicated that poor sleep quality was common among internal migrant workers in the service industry. Older age, long working hours, and poor physical and psychiatric health status contributed to poor sleep quality. Compared to males, sleep quality in females was more likely to be impacted by depression. Optimum working hours and physical and psychological health are critical to improving sleep quality. Interventions for ameliorating sleep quality might have different priorities for males and females.
