“Where are all the lonely people?” A population-based study of high-risk groups across the life span

Loneliness is a prevalent and urgent public health issue. Optimal planning of community approaches to loneliness requires a differentiated understanding of loneliness across the life span. We identified groups at high risk of loneliness by exploring the relationship between loneliness and socio-demographic and health-related factors across multiple age groups.

This was a combined population-based questionnaire survey and register data study based on a representative sample, including 33,285 Danish individuals aged 16–102 years. Loneliness was measured using the Three-Item Loneliness Scale.

The relation between loneliness and age took a shallow U-shaped distribution. Ethnic minority status, receiving disability pensions or being unemployed, living alone, prolonged mental disorder, and psychiatric treatment were strongly associated with severe loneliness. Socio-demographic and health-related factors were associated with an increased risk of severe loneliness in specific age groups. Being female, having a low educational level and living in a deprived area were only associated with loneliness in adolescence/emerging adulthood. Receiving disability pensions and living alone (i.e., divorced), on the other hand, were strongly associated with loneliness in early and middle adulthood and young-old age.

Ethnic minority status, living alone, and prolonged mental disorder may well be key factors in determining the generic level of loneliness in a given population. Other conditions are associated with an increased risk of severe loneliness in specific age groups and may moderate the age–loneliness relation. These findings may help to identify populations within communities at risk of loneliness and thereby support the implementation of policies and public health interventions across the life span.