Abstract— Geographic context plays a fundamental role in shaping disease distribution, transmission dynamics, and health outcomes; however, systematic comparisons between mainland and island regions remain limited and fragmented. Existing studies often focus on individual diseases, specific regions, or isolated determinants such as mobility or environment, providing valuable insights but lacking an integrated perspective that captures how geography interacts with epidemiological, socioeconomic, and healthcare factors. As a result, public health strategies are frequently developed using generalized assumptions that may not adequately reflect the distinct vulnerabilities and strengths of mainland and island populations. This paper synthesizes existing evidence to compare disease patterns between mainland and island regions, with particular emphasis on differences in disease burden, transmission dynamics, environmental and socioeconomic drivers, and mortality profiles. By integrating findings across infectious and non-communicable diseases and incorporating real-world mortality evidence, the study provides a consolidated overview of how geographic settings influence health risks and outcomes. Understanding these differences is important for improving disease surveillance, preparedness, and policy design. The findings highlight the need for geography-aware public health approaches, harmonized and spatially disaggregated health data, and context-specific intervention strategies. Such an approach can enhance the effectiveness of disease prevention efforts and support more equitable health planning across diverse geographic settings.

Keywords— Mainland regions, Island populations, Disease burden, Mortality patterns, Transmission dynamics, Public health policy.

                                                                                                                                                      I.     Introduction

Geographical context plays a critical role in shaping disease distribution, transmission dynamics, and population health outcomes. In particular, mainland and island regions exhibit distinct epidemiological characteristics due to differences in population density, mobility, environmental exposure, healthcare accessibility, and socioeconomic structures. Understanding these differences is essential for designing location-specific disease surveillance systems, prevention strategies, and public health policies.

Islands are often characterized by geographical isolation, limited population inflow, and controlled points of entry, which can reduce exposure to certain infectious diseases but simultaneously increase vulnerability to outbreak amplification, delayed medical response, and limited healthcare resources. In contrast, mainland regions typically experience higher population density, extensive transportation networks, and increased human mobility, facilitating faster disease transmission and broader exposure to both infectious and non-communicable diseases [1–3].

Previous studies have demonstrated that island populations may experience lower incidence of some communicable diseases, particularly during early epidemic phases, due to restricted travel and natural quarantine effects [4,5]. However, islands also face unique health challenges, including higher prevalence of chronic diseases, limited specialist care, dependency on external medical supply chains, and heightened sensitivity to environmental changes such as climate variability and extreme weather events [6–8].

From an environmental perspective, climatic conditions, biodiversity, and vector ecology differ significantly between mainland and island settings, influencing the spread of vector-borne diseases such as dengue, malaria, and Zika virus [9–11]. Islands may also experience ecosystem fragility, where minor environmental disruptions can produce disproportionate health impacts [12].

Socioeconomic disparities further contribute to disease heterogeneity between mainland and island populations. Factors such as income distribution, education levels, occupational exposure, and healthcare infrastructure have been shown to significantly influence disease burden and health outcomes [13–15]. Additionally, demographic characteristics such as aging populations are often more pronounced on islands, increasing susceptibility to non-communicable diseases and healthcare system strain [16].

The recent COVID-19 pandemic highlighted stark contrasts between mainland and island disease dynamics, with several island nations demonstrating delayed onset, lower case numbers, and reduced mortality through early border control and isolation measures, while mainland regions faced rapid community transmission [17–19]. These observations underscore the importance of geographical context in epidemic preparedness and response.

experience higher population density, extensive transportation networks, and increased human mobility, facilitating faster disease transmission and broader exposure to both infectious and non-communicable diseases ^[1–3].