Relation between Loneliness and Social Isolation and Chronic Diseases in Australian Youths

By Aleksandr Yang, Australia

Abstract:

Loneliness and social isolation are conceptualized as social determinants of mental health, influencing emotional well-being through the disruption of social belonging, perceived support, and relational security. The "silent epidemic" of loneliness and social isolation is emerging as critical public health concerns among Australian adolescents (Publica Institute 2023). Meanwhile, almost half of Australian youths now live with a chronic disease or developmental condition (Publica Institute 2023) (Mahoney and Fisher 2025). This study aims to isolate the effects of loneliness and social isolation among Australian youths aged 12–24, through precise measurement approaches: Social Network Mapping for subjective loneliness, Ecological Momentary Assessment (EMA) for real-time social isolation, and biological markers including HbA1c (metabolic dysfunction) and inflammatory cytokines (cardiovascular risk). Structural Equation Modelling (SEM) will model these complex biopsychosocial relationships. Findings will inform integrated health interventions that target both mental and physical well-being early in life.

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Introduction:

The health status of young Australians is deteriorating markedly. Over 58% of individuals aged 15–24 now live with at least one chronic physical condition such as asthma, overweight/obesity, or diabetes, while 40% experience a mental health disorder ("Health of Young People 2023"). Beyond the rise in chronic physical ailments, there is a notable surge in mental health issues: loneliness, once predominantly associated with the elderly, is now alarmingly prevalent among young Australians. 37% of individuals aged 18 and 25 reported experiencing significant loneliness (Publica Institute 2023). Current research overwhelmingly centres on adult populations, neglecting the unique vulnerabilities and developmental contexts of adolescents. Psychosocially, adolescents are forming critical aspects of identity and social belonging, making them more susceptible to the harmful effects of loneliness compared to adults, who typically possess more stable self-concepts and social networks (Orben et al. 2020). This study will address research gaps by focusing exclusively on the youth, isolating loneliness and social isolation as distinct constructs, and employing accurate, valid, and biologically anchored measurement approaches to explore their distinct relationships with chronic disease risk.

Literature Review:

The distinction between loneliness and social isolation was clarified: Loneliness refers to the subjective perception of inadequate social connection, whereas social isolation denotes the objective lack of social contact (Hong et al. 2023). Loneliness is a stronger predictor of adverse health outcomes than isolation alone, emphasizing the necessity of addressing both dimensions independently.

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Social disconnection has been widely linked to adverse health outcomes, primarily in adult populations. However, adolescents exhibit heightened vulnerability to social adversity due to ongoing neurodevelopmental processes, including the maturation of social cognition and emotion regulation systems (Blakemore and Mills 2014). The concept of biological embedding posits that early life experiences, such as chronic loneliness or social isolation, can become encoded into physiological systems, influencing disease risk across the lifespan (Lacey et al. 2014). For example, children who experience social isolation show elevated markers of systemic inflammation (CRP, IL-6) and dysregulated metabolic profiles (e.g., insulin resistance) in adulthood (Caspi et al. 2006; Danese and Baldwin 2017). Such biological alterations are implicated in the development of cardiovascular diseases, type 2 diabetes, and other chronic illnesses.

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However, there are interventions targeting social isolation that have produced inconsistent health outcomes (Veazie et al. 2019), often because they failed to address subjective loneliness. While cultural factors may further modulate the effects of social disconnection (Miyawaki 2015), underlining the importance of culturally sensitive, youth-focused research. In sum, existing literature indicates an urgent need for youth-specific, biologically anchored research that separately examines loneliness and social isolation with precision.

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Hypothesis and Objective:

This study hypothesizes that loneliness and social isolation will demonstrate distinct and independent associations with biological risk markers among adolescents, yet both will exert detrimental effects on physical health outcomes. Specifically, it is expected that loneliness will exhibit a stronger association with chronic disease risk factors, such as elevated inflammation and cardiovascular biomarkers. By disentangling these psychosocial constructs, the study aims to clarify their unique contributions to adolescent health deterioration. The findings are anticipated to provide valuable predictive insights into future chronic disease risks, thereby informing early identification strategies and preventative health interventions during critical developmental periods.

Methodology:​ 

This study will employ a mixed-method, cross-sectional setup to investigate the relationships between loneliness, social isolation, and the prevalence of chronic diseases among Australian youths aged 12 to 24. A cross-sectional framework enables simultaneous assessment of social experiences, psychological outcomes, and biological markers, while mixed-methods integration enhances both quantitative modelling and qualitative depth (Creswell and Plano Clark 2017). A nationally representative sample of 385 participants will be recruited to achieve a 95% confidence level with a 5% margin of error from a youth population of approximately 4.2 million. Stratified random sampling will ensure representation across gender, geographic location (urban versus regional), and cultural backgrounds, including Aboriginal and Torres Strait Islander youths.

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Subjective loneliness will be assessed using Social Network Mapping, wherein participants visually depict the structure, closeness, and perceived quality of their social relationships. This captures relational subjectivity beyond traditional numeric survey scales, representing the variable of loneliness with high accuracy. Objective social isolation will be measured using Ecological Momentary Assessment (EMA), involving smartphone prompts administered three times daily over one week, querying real-time experiences such as "How connected do you feel to others at this moment?” and "How many people have you interacted with today?" EMA is selected for its capacity to reduce recall bias and to capture the fluctuating, moment-to-moment nature of social disconnection (Shiffman et al. 2008). Chronic disease risk will be evaluated both through self-reported checklists and biological measures. Participants will complete a checklist adapted from the Australian Institute of Health and Welfare's chronic conditions classifications, covering asthma, diabetes, obesity, ADHD, and ASD. To provide objective biological data, a subset of participants will be invited to undergo non-invasive biological testing: capillary blood samples (via finger-prick kits) will be used to assess glycated hemoglobin (HbA1c) levels, indicative of long-term glucose regulation and early diabetic risk; inflammatory cytokine panels (e.g., IL-6, TNF-α) will be assessed to detect low-grade systemic inflammation associated with cardiovascular risk (Danese and Baldwin 2017).

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Data collection for Social Network Mapping and EMAs will be real-time via online platforms, and mail-in collection kits will be distributed for biological sampling, following protocols validated in adolescent health research (Shirtcliff et al. 2005). Data analysis will involve descriptive statistics to characterize the sample, bivariate correlations to explore associations between mental and physical health outcomes, the Structural Equation Modelling (SEM) will test hypothesized pathways linking social experiences to biological and psychological outcomes.

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References :

Caspi, Avshalom, et al. "Socially Isolated Children 20 Years Later: Risk of Cardiovascular Disease." Archives of Pediatrics & Adolescent Medicine, vol. 160, no. 8, 2006, pp. 805–811. https://doi.org/10.1001/archpedi.160.8.805

Christiansen, Jesper, et al. "Associations of Loneliness and Social Isolation with Physical and Mental Health among Adolescents and Young Adults." Perspectives in Public Health, 2021. https://doi.org/10.1177/17579139211016077

Freak-Poli, Rosanne, et al. "Does Social Isolation, Social Support or Loneliness Influence Health or Well-Being after a Cardiovascular Disease Event? A Narrative Thematic Systematic Review." Health & Social Care in the Community, 2022. https://doi.org/10.1111/hsc.13427

Hong, Jason H., et al. "Are Loneliness and Social Isolation Equal Threats to Health and WellBeing? An Outcome-Wide Longitudinal Approach." SSM - Population Health, vol. 23, 2023. https://doi.org/10.1016/j.ssmph.2023.101348

Lacey, Rosie E., et al. "Social Isolation in Childhood and Adult Inflammation: Evidence from the National Child Development Study." Psychoneuroendocrinology, vol. 50, 2014, pp. 85– 94. https://doi.org/10.1016/j.psyneuen.2014.08.007

Mahoney, Andrew E.J., and Paul A. Fisher. "A Systematic Review of Loneliness and Social Isolation Scales Used in Adolescents." Health Promotion Journal of Australia, vol. 36, no. 1, 2025, pp. 6–18. https://doi.org/10.1016/j.hpja.2024.100063

Miyawaki, Christina E. "Association of Social Isolation and Health across Different Racial and Ethnic Groups of Older Americans." Ageing and Society, vol. 36, no. 5, 2015, pp. 1041– 1068. https://doi.org/10.1017/S0144686X14000634

Russell, Daniel. "UCLA Loneliness Scale (Version 3): Reliability, Validity, and Factor Structure." Journal of Personality Assessment, vol. 66, no. 1, 1996, pp. 20–40. https://doi.org/10.1207/s15327752jpa6601_2

Shirtcliff, E. A., Granger, D. A., Booth, A., & Johnson, D. (2005). Low salivary cortisol levels and externalizing behavior problems in youth. Development and Psychopathology, 17(1), 167–184. https://doi.org/10.1017/S0954579405050091

Veazie, Shannon, et al. "Addressing Social Isolation to Improve the Health of Older Adults: A Rapid Review." Europe PMC, 2019. https://europepmc.org/article/nbk/nbk537909

Australian Institute of Health and Welfare. Health of Young People 2023. AIHW, 2023. https://www.aihw.gov.au/reports/children-youth/health-of-young-people

Publica Institute. The Silent Epidemic: Loneliness among Australian Youth. Publica Institute, 2023. https://publica.org.au/the-silent-epidemic-unravelling-the-complexities-of-lonelinessamong-young-australians/