Loneliness in Older Adults in the USA and Germany: Measurement Invariance and Validation

Abstract

Loneliness is a subjective experience characterized by the distress that accompanies a perceived deficit in social relationship quantity and especially quality. Feelings of loneliness increase risk for morbidity and mortality, and these health costs are particularly evident in older age and as lonely feelings persist over time. The scope of the problem of loneliness in older age is not yet well understood, however. To accelerate the development of a cumulative knowledge base on loneliness, we harmonize data from three nationally representative samples—the Health and Retirement Study and the National Social Life, Health, and Aging Project in the United States, and the Socio-Economic Panel in Germany—to investigate the measurement invariance of a 3-item loneliness measure and validate the loneliness construct across surveys. A series of multi-group confirmatory factor analyses provided support for strict measurement invariance. Validation was demonstrated with equivalent inverse associations of loneliness with self-rated health, marital status, and frequency of social activity across surveys and countries. We articulate a method to harmonize data across national surveys and encourage replication and extension to expand the scope of loneliness research.