Effects of volunteering over six months on loneliness, social and mental health outcomes among older adults: The HEAL-HOA Dual Randomized Controlled Trial

Objective: To determine the beneficial effects of volunteering as lay counselor via telephone on own loneliness, social network engagement, perceived social support, stress, anxiety, and depressive symptoms among Chinese older adults in Hong Kong during the COVID-19 pandemic. Design, Setting, Intervention, and Participants: "Helping Alleviate Loneliness in Hong Kong Older Adults" (HEAL-HOA), a dual randomized controlled trial, was implemented to test effects of telephone-based psychosocial interventions delivered by older-adult volunteers for low-income lonely older adults. To evaluate the effects of volunteering on loneliness, we randomized 375 individuals ages 50-70 into a volunteering condition versus an active control (psychoeducation with social gatherings). Following a 6-week training, participants in the volunteering condition, delivered tele-interventions to older intervention recipients. Measurement: The primary outcome was loneliness measured with the UCLA Loneliness Scale. Secondary outcomes were loneliness measured with the De Jong Gierveld Scale (DJG), social network engagement, perceived social support, perceived stress, anxiety, and depressive symptoms. Assessments were completed before training (baseline) and immediately after the 6-month