Food for Thought: Investigating Adolescent Nutrition, Health Behaviours, and Mental Health and Their Association with the Onset of Chronic Inflammation

Abstract

Chronic inflammation plays an important role in disease aetiology, but our understanding of its prevalence and associated risk factors in adolescents is limited – a population with worsening health behaviours and disease rates.

This thesis aims to investigate the global prevalence of chronic inflammation in adolescents and understand how health behaviours, mental health and socio-demographic factors associate with inflammation and disease in Australian adolescents.

Study 1 is a meta-analysis of chronic inflammation prevalence in adolescents worldwide. Results indicate inflammation levels in this population is approaching the threshold for chronic inflammation, and that those who are overweight/obese are more likely to meet this threshold. Study 2 examines in a large cohort of Australian adolescents how multiple health behaviours, mental health, and socio-demographic variables associate with 11 non-communicable diseases/developmental conditions. Almost half (46%) of adolescents have one or more of these diseases/conditions and tobacco, alcohol, ultra-processed food intake and poor mental health are associated with each of these. Study 3 examines associations between adolescent-perceived parental monitoring and dietary intake. Results reveal a complex relationship, with higher parental monitoring associated with increased vegetable and lower ultra-processed food intake, but also insufficient fruit and excessive sugar-sweetened beverage intake. Study 4 is the first to test the feasibility of assessing inflammatory markers via dried blood spot collection in a school setting. Results establish feasibility and find associations between diet and inflammation largely align with the adult literature, indicating adolescents are not immune to the biological impacts of poor dietary intake.

Overall, this thesis advances the fields of prevention and epidemiology by identifying modifiable targets for adolescent health, laying the foundations for future causal analysis.