ReviewA meta-analysis of the prevalence of depressive symptoms in Chinese older adults
Introduction
The rapid development of the economy and the transition of the population structure have significantly accelerated the aging of the population in China. The number of older adults 60 years and above has reached nearly 174 million in the country, with an average annual increase rate of 3.28%. In 2051, the older adult population in China is expected to reach a peak of 437 million (Fan, 2008). With the tendency toward aging of its population, China faces practical challenges such as an incomplete social security system, increasing “empty nest” families and imperfect implementation of rural pension, which barely meets the multiple needs of older adults, including economic support, physical care and spiritual comfort. Geriatric depression has been the focus of researchers because depression is the most frequent cause of emotional suffering in later life. Geriatric depression significantly reduces quality of life (Blazer, 2003, Geerlings et al., 2001) and is associated with a high risk for suicide (Kaneko, Motohashi, Sasaki, & Yamaji, 2007).
In China, depressive symptoms in older adults first captured the attention of researchers in the 1980s. Since the 1990s, a large number of studies concerning depression in older adults emerged (Zhang, Xu, & Nie, 2011). However, the prevalence of depressive symptoms in Chinese older adults differed greatly from 6.35% (Chen, Zhang, & Gao, 2007) to 60.30% (Jia et al., 2011). This variation may be attributed to the following reasons. (1) The criteria of the measuring tools used in these studies were not consistent. For example, GDS and CES-D are two commonly used filtering tools for geriatric depression in China (Niu & Li, 2010). GDS is specifically developed for older adults, and the survey excludes somatisation, which possibly occurs with aging. However, CES-D includes this item. In addition, the items and scoring criteria are also different between GDS and CES-D. For example, the GDS includes 30-items, and maximum overall score is 30. The participant with a score of 11 points or higher will be considered as significant depressive symptoms. While, the CES-D includes 20-items and four subscales: Depressed Affect, Somatic Symptoms, Lack of Well-Being, and Interpersonal Problems (Nguyen & Zonderman, 2006). The respondents with scores equal or above 16 were defined as depressed (Radloff & Locke, 1986). All of these may lead to the varying sensitivity of the two tools. (2) The surveys involved were based on biased samples. Different samples of gender, age, degree of education and marital status may have affected the conclusions (Chen et al., 2012, Yu et al., 2012, Zhang et al., 2012a, Zhang et al., 2012b). (3) Rapid economic development and advanced industrialisation and urbanisation have caused the Chinese society to go through a dramatic transition. Numerous protective factors, such as lower urbanisation level, strong social support and a filial culture of depressive symptoms in older adults, have changed or disappeared during the last two decades. Thus, the prevalence of depressive symptoms in Chinese older adults increased (Chen et al., 1999, Yu et al., 2012). However, longitudinal data results of the changes in depression symptoms in older adults in China are still lacking.
Thus, to understand the prevalence of depressive symptoms in Chinese older adults more accurately and comprehensively, a meta-analysis can be adopted to avoid differences in individual research from biased samples and demographic factors. This analysis is conducive to achieving more accurate and general conclusions from several aspects of multiple studies. For example, in the meta-analysis of the prevalence of depressive symptoms in Chinese older adults between the late 1980s and early 1990s, Chen et al. found that the depression occurrence rate in older adults in Mainland China was 3.86%, which was far less than the 12.00% in Western countries (Chen et al., 1999, Copeland et al., 1999). However, in a recent meta-analysis on the prevalence of depressive symptoms in Chinese older adults from 2000 to 2010, Zhang and Xu et al. (2012) found that the pooled prevalence of geriatric depressive symptoms has been up to 22.7%. These two studies have several limitations. (1) The amount of literature for the final conclusion and the studies used to examine influence factors were insufficient (Zhang, Xu, & Nie, 2011). (2) The time span was relatively limited (Chen et al., 1999, Zhang et al., 2011a). (3) The potential changes in the prevalence of depressive symptoms in Chinese older adults along with the time were not examined.
Therefore, this study aims to comprehensively analyse related studies on the prevalence of depressive symptoms in Chinese older adults under an extensive time span, as well as to examine birth cohort changes in the prevalence of depressive symptoms. At the same time, the moderate effect of variables such as measurement tool, gender, age, degree of education and marital status on the prevalence of depressive symptoms can also be examined.
Section snippets
Literature search
Literature search was performed on the Chinese National Knowledge Infrastructure (CNKI), Chinese Biomedical Database, Wanfang, PubMed and PyschINFO. All databases were searched from 1979 (the earliest year available on the CNKI database) to 2012. The search terms were ‘older adults’, ‘elderly’, ‘depression’, ‘depressive symptoms’, ‘GDS’ and ‘CES-D’. Other eligible articles were also identified by searching the references cited in the obtained published articles. Abstracts or unpublished
Search results
The results of the initial search and exclusions are shown in Fig. 1. A total of 81 eligible studies focused on the prevalence of depressive symptoms in Chinese older adults. The characteristics of these studies were summarised in Table 1.
Pooled prevalence of depressive symptoms and potential moderators
A total of 81 eligible studies met the inclusion criteria, involving a total sample size of 88,417 subjects, of which 21,129 cases with depressive symptoms were selected. Table 2 shows the pooled prevalence (95% CI) and moderate effect of the variables, such
Pooled prevalence of depressive symptoms and ascending trend with the year
With the meta-analysis of studies on the prevalence of depressive symptoms in Chinese older adults in the past 25 years, the overall prevalence of depressive symptoms in Chinese older adults have reached 23.6% (95% CI: 20.3–27.2%), which is similar to the findings of Zhang, Xu, and Nie (2011). These findings were much higher than the figure reported two decades ago (Chen et al., 1999; Fan & Chen, 1994; Meng and Xiang, 1997, Wu and Zhang, 1989). In a recent survey of 4945 community older adults
Conclusion
The meta-analysis of 81 studies on the prevalence of depressive symptoms in Chinese older adults from 1987 to 2012 found that (1) the pooled prevalence of depressive symptoms in Chinese older adults has reached 23.6% (95% CI: 20.3–27.2%) and may increase with time; and that (2) significant differences exist in the prevalence of depressive symptoms in Chinese older adults in terms of measurement tool, gender, degree of education and marital status, but not in terms of age.
Conflict of interest statement
None.
Role of funding source
This research was supported by the project of the Southwest University for Researcher Groups (TR201204-1, 7), by the Social Sciences Foundation of the Ministry of Education of China (08JJDXLX268), by the Chongqing Postdoctoral Sustentation Fund (XM20120031), and the Key Humanity Social Science Research Institute in Chongqing (20500111).
Acknowledgments
We are grateful to the anonymous reviewers for their valuable suggestions on improving the manuscript.
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