Effects of Acculturation On Depression Among Older Immigrants: A Systematic Review and Meta-Analysis

Background and Purpose: Older immigrants are at risk of developing depression in the process of acculturation. Although research on acculturation has been increasing over the past two decades, there have not been any published systematic reviews on the effects of acculturation on depression among elderly members of ethnic minorities. The purpose of this meta-analysis is to summarize the empirical evidence concerning the relationship between acculturation and depression among older immigrants across race and ethnicity and to compare the use of different measurements for acculturation and depression. 

Method: Using six electronic databases, 311 publications were identified; of these, 10 full-text articles met the inclusion criteria: 1) peer reviewed, 2) written in English or Korean, 3) quantitative, and 4) related to key terms such as acculturation, depression, immigration, and older adults (+50 years). However, un-indexed studies or gray literature were excluded in the systematic review. Additionally, in order to gauge the impact of the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 in the U.S., studies conducted before January 1997 were excluded. Studies that did not provide data for effect size calculations or were multiple reports from a single study were excluded. Ultimately, 10 articles were assessed for study quality. Among the 10 articles, one had two sub-samples, one had two depression measures, and three had more than two acculturation subscales or measures; therefore, 20 correlations were synthesized and analyzed as an effect size statistic for the meta-analysis.

Results: The included studies had samples with different ethnic backgrounds (6 Korean, 1 Chinese, 1 Indian, 1 Hispanic, and 1 Muslim). Under the random-effects model, the acculturation effects were consistent across studies, and the summary effect size was -0.20 (95% CI = -0.25, -0.15), indicating that more acculturated older immigrants were less depressed. Older immigrants from Korea (ES = -0.21; CI = -0.27, -0.15) and China (ES = -0.26; CI = -0.38, -0.13) had more serious acculturation impact on depression compared to the other ethnic groups such as Indians (ES = -0.17; CI = -0.36, 0.3), Hispanics (ES = -0.14; CI = -0.19, -0.09), and Muslims (ES = -0.07; CI = -0.30, 0.17). The summary effect of language (ES = -0.25; CI = -0.32, -0.18) to the measurement of acculturation was stronger than cultural values (ES = -0.24; CI = -0.32, -0.16), behaviors and life-styles (ES = -0.21; CI = -0.26, -0.16), and period of residency (ES = -0.10; CI = -0.27, -0.09). The acculturation effects on depression scales were different: GDS (ES = -0.24; CI = -0.28, -0.20) and CESD (ES = -0.20; CI = -0.25, -0.15).    

Conclusions and Implications: Acculturation to the host culture had an effect on depression among older immigrants, and the magnitude of effect was different. Depression scales may have different detection rates, and racial and ethnic difference should be considered for prevention and treatment on depression. Language and cultural competent programs for older immigrants may be effective for reduction of depression. For future studies, comparisons between a greater variety of ethnic groups and gender roles are needed.