Support exchange between siblings in later life: the role of "core-kinlessness" and geographic proximity

As people have fewer children and remain single, siblings may become more active in family networks of older adults who lack a partner, children, or both-referred to as "core-kinless." This study examines the association between the absence of children and/or a partner and the exchange of support between siblings and how intragenerational geographic proximity shapes these associations, addressing both giving and receiving practical help and giving personal care.

Data from the Generational Transmissions in Finland project (adults aged 78-74 in 2018 and their siblings), linked with register data, were analyzed using multilevel ordinal logistic regressions to examine the frequency of giving and receiving practical help, and logistic regressions providing personal care.

Siblings were found to be active supporters in later life. Partnerless older adults-particularly never married-were more likely to receive practical help from siblings than those with partners. Childlessness alone did not increase sibling support, but core-kinless older adults received the highest levels of help and provided more assistance and personal care to siblings, even across long distances. Geographic proximity strengthened support exchanges, but core-kinlessness remained a strong predictor of support exchange regardless of distance. Finally, a 10 km threshold seems adequate for approximating help and care exchanges between siblings.

Findings highlight siblings' role as a compensatory source of support in later life, especially if they are core-kinless. Future research and policy should broaden caregiving definitions to include siblings and recognize core-kinless older adults as an underappreciated resource of help and care within family networks.