Social network and severe lower respiratory tract infections in older adults: findings from a Swedish longitudinal population-based study

Abstract

Objectives: To investigate the association between social network and the risk and prognosis of severe lower respiratory tract infections (LRTIs) in older adults.

Methods: Data from Swedish hospital records were matched with the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). Social network was operationalized as social connections and social support, based on different self-reported variables, and categorized as low, medium, and high. The risk of severe LRTI and related outcomes were assessed using Cox, Poisson, and logistic regression models where appropriate.

Results: A total of 362 individuals experienced LRTI-related hospitalizations between 2001 and 2016 (479 total hospitalizations). High levels of social support decreased the hazard of incident LRTI by 29% (hazard ratio 0.71, 95% confidence interval [CI] 0.52-0.96), the hospital length of stay by 21% (incidence rate ratio 0.79, 95% CI 0.65-0.97), and the risk of 30-day mortality by 92% (odds ratio 0.08, 95% CI 0.01-0.68), but was a risk factor for 30-day readmission (odds ratio 3.16, 95% CI 1.38-7.24). High levels of social connections were associated with a higher risk of incident LRTI in women and those with dementia and/or slow walking speed (P_interaction <0.05).

Conclusion: Older individuals' quality of social support seems to be a stronger determinant of LRTI incidence and prognosis than the quantity of their social connections. These findings may inform evidence-based policies aimed at preventing LRTIs in older adults.

Keywords: Aging; Hospital admission; Respiratory tract infections; Social network; Social support.