Limited family ties, friendship, and contextual variation in loneliness risk across 25 countries.

Loneliness is linked to higher mortality and poorer health worldwide. As the global population of individuals who are unpartnered and childless grows, public health concerns about social isolation have risen. Sociological theories distinguish between having fewer ties, being socially isolated, and being lonely while gerontological theories emphasize how aging adults prioritize smaller, high-quality relationships. Yet, norms about family, friendship, and loneliness also differ by country contexts such as culture and development. Therefore, while close non-family ties (e.g., friendship) might reduce loneliness, particularly among those who lack partners or children, these processes likely differ across country contexts. Consequently, it remains unclear 1) whether lacking partners or children is associated with various dimensions of loneliness, 2) whether friendship buffers risk of loneliness, and 3) if and how these processes differ across societies. This study examines being unpartnered or childless, friend contact, and loneliness among those aged 45+ (N = 19,289) across 25 countries using data from the International Social Survey Programme (2017) and country-level indicators from the World Health Organization and World Values Survey. Being unpartnered is particularly associated with loneliness-especially lacking companionship. Yet, frequent friend contact likely buffers loneliness across all outcomes-especially for the unpartnered. Those in countries that place a high value on family and especially friendship are at lower risk of loneliness. These findings are discussed considering changing family structures, the potential role of friendship in compensating for limited family ties, and differential risks of loneliness by country context.