Date Published: February 24, 2017
Publisher: Public Library of Science
Author(s): Xiao-Lan Cao, Shi-Bin Wang, Bao-Liang Zhong, Ling Zhang, Gabor S. Ungvari, Chee H. Ng, Lu Li, Helen F. K. Chiu, Grace K. I. Lok, Jian-Ping Lu, Fu-Jun Jia, Yu-Tao Xiang, Russell Jude de Souza.
This is the first meta-analysis of the pooled prevalence of insomnia in the general population of China. A systematic literature search was conducted via the following databases: PubMed, PsycINFO, EMBASE and Chinese databases (China National Knowledge Interne (CNKI), WanFang Data and SinoMed). Statistical analyses were performed using the Comprehensive Meta-Analysis program. A total of 17 studies with 115,988 participants met the inclusion criteria for the analysis. The pooled prevalence of insomnia in China was 15.0% (95% Confidence interval [CI]: 12.1%-18.5%). No significant difference was found in the prevalence between genders or across time period. The pooled prevalence of insomnia in population with a mean age of 43.7 years and older (11.6%; 95% CI: 7.5%-17.6%) was significantly lower than in those with a mean age younger than 43.7 years (20.4%; 95% CI: 14.2%-28.2%). The prevalence of insomnia was significantly affected by the type of assessment tools (Q = 14.1, P = 0.001). The general population prevalence of insomnia in China is lower than those reported in Western countries but similar to those in Asian countries. Younger Chinese adults appear to suffer from more insomnia than older adults.
Insomnia, which is characterized by difficulty initiating and maintaining sleep and/or waking up too early, appears to be one of the most frequent sleep complaints in the general population . For example, approximately a third of the adult population in the USA suffer from insomnia . It has been shown that insomnia has significant negative impact on daily functioning and is associated with work absenteeism, considerable impairment of quality of life, and increased medical and societal costs [3,4]. In addition, insomnia is frequently associated with a variety of psychiatric disorders, especially depression and anxiety [1,5,6].
This was the first meta-analysis of the general population in China examining the prevalence of insomnia. Most studies assessed the prevalence of insomnia symptoms using the PSQI or AIS, while five studies used standardized questions “yes-no” answers without any restrictive criteria or their frequency. No studies used insomnia diagnoses according to DSM-IV. The pooled prevalence of insomnia in China was 15.0%, which was lower than those in many Western countries (e.g., 37.2% in France and Italy, 27.1% in USA and 50.5% in Poland) [2,8], but similar to findings reported from other Asian countries (e.g., 15.3% in Japan and 17.3% in Singapore) . However, the results of studies should be viewed with caution due to the confounding effects caused by discrepancy in sample sizes, response rates, sampling methods and measures on insomnia. In addition, no publication bias was found in this study which may be related to the nature of prevalence studies. Unlike meta-analysis comparing two treatments where negative results are often not published, prevalence studies in the general population are less likely to be subjected to publication bias especially if the sample size is adequate.
This was the first meta-analysis of the pooled prevalence of insomnia in the general population of China. The pooled prevalence of insomnia is lower than those reported in Western countries, but similar to those in other Asian countries. Younger adults are more likely to suffer from insomnia than older adults.