Association between salivary oxytocin concentration and social loneliness in older adults: Findings from an...

loneliness, whether social or emotional, is a significant public health issue due to its substantial impact on physical and mental health. Building on studies showing that oxytocin levels rise during social interactions, we hypothesised that oxytocin concentration associates with loneliness, and that an intervention aimed at alleviating loneliness could be accompanied by changes in peripheral oxytocin concentration.

An intervention based on a 13-week multimodal programme (Clinicaltrials.gov identifier: NCT06382181) was conducted with 62 participants (79% women) aged 60 or over, recruited from municipal activity centres in Valencia, Spain. The study was carried out between March and June 2023. The assessment used sociodemographic questionnaires and the De Jong-Gierveld Loneliness Scale, as well as saliva samples collected before and after the multimodal programme aimed at alleviating loneliness in older individuals. Bivariate analyses were used to examine the association between sociodemographic factors, oxytocin and loneliness, and oxytocin concentrations before and after the intervention were compared using the Wilcoxon signed-rank test. A linear regression analysis was performed to determine which variable predicts changes in oxytocin concentration.

An increase in salivary oxytocin concentration was observed following the intervention across the entire sample. In the sub-sample of individuals who reported loneliness at baseline, oxytocin concentration in saliva correlated significantly with baseline loneliness (social loneliness, p = 0.003; total loneliness, p = 0.025). Thus, the more intense the perception of loneliness, the lower the baseline levels of oxytocin. Correlations were found between baseline oxytocin and age (p = 0.011, inverse correlation) and level of education (p = 0.019, direct correlation). A direct and significant correlation was observed between loneliness (emotional, social and total) and the number of children (p = 0.04, p = 0.01, p = 0.02, respectively), as well as between social loneliness and caring for grandchildren (p = 0.04). Multivariate analysis revealed that caring for grandchildren had a significant effect (p = 0.008) on changes in oxytocin levels following the intervention.

The results suggest that salivary oxytocin may be associated with loneliness in older adults; however, further validation is required before salivary oxytocin can be considered a reliable biomarker of loneliness.