The Stress-Buffering Effect of Social Support on Socio-Economic Disparities in Mental Health among Cancer Survivors.

Abstract

Background: Low socio-economic status (SES) is considered a major chronic stressor and is frequently associated with worse mental health among cancer survivors. We investigated the extent to which social support could mitigate the negative impact of low SES on the mental health of individuals with a history of cancer.

Method: Participants were cancer survivors identified in two nationally representative surveys conducted in Spain in 2017 (n = 1,143) and 2023 (n = 980). SES was measured with the social class index of the Spanish Society of Epidemiology. Social support was measured with the Duke-UNC questionnaire and the Oslo Social Support Scale. Mental health outcomes included psychological distress (General Health Questionnaire-12), mental well-being (WHO-5 Index), and depression (Patient Health Questionnaire-8). The moderating role of social support was examined in a multiple regression framework, complemented by generalized additive models to capture potential non-linear effects.

Results: Mental health vulnerability was highest among individuals with low levels of social support, where no SES-related differences were observed. Under medium social support, low SES was linked to higher psychological distress (B = 0.24, 95% confidence intervals, CI [0.05, 0.42]), lower mental well-being (B = -6.08 [-1.98, -10.18]), and higher rates of depression (OR = 2.78 [1.52, 5.00]). High social support buffered this effect, improving mental health among cancer survivors with low SES and reducing SES differences. Sub-group analyses revealed that this buffering effect was less evident among women, for whom inequalities persisted regardless of social support levels.

Discussion: High social support consistently attenuated SES disparities across three different mental health outcomes, albeit less effectively among women.