Curvilinear association between loneliness and hair cortisol concentrations in community-dwelling older adults at elevated cardiovascular risk

This study investigated the curvilinear relationship between loneliness and hair cortisol concentration (HCC) in 126 older adults aged 60 and above at elevated cardiovascular risk in China. Using the De Jong Gierveld Loneliness Scale and liquid chromatography-tandem mass spectrometry, researchers found a significant curvilinear association, with HCC higher at low-to-moderate loneliness levels and lower at higher loneliness levels. The quadratic association remained significant after adjusting for various covariates, although sensitivity analyses showed that the results were influenced by high-influence cases. These findings suggest a nonlinear relationship between loneliness and cortisol output, potentially explaining inconsistencies in previous research and emphasizing the need for further longitudinal studies.