Environmental exposures, microbiome dynamics and chronic disease risk in climate-vulnerable regions:...

Environmental factors such as air pollution, weather events, and ambient toxins are major contributors to human disease, with disproportionate impacts on vulnerable populations. In Puerto Rico, chronic exposure to air pollution and ecological disruption poses significant public health risks, particularly for cancer and other chronic conditions. These risks are unevenly distributed, disproportionately affecting children and older adults, groups central to community resilience yet highly susceptible to pollution-related health effects. This perspective review synthesizes emerging evidence linking chronic air pollution and environmental exposures to cancer, respiratory and cardiovascular disease, and microbiome alterations that may mediate long-term health trajectories. Drawing on interdisciplinary efforts from the Caribbean Cancer Research Center on Environmental and Natural Hazards, the Center for the Promotion of Cancer Health Equity, the Caribbean Collaborative Action Network, a NOAA CAP/RISA Team, and the Puerto Rico Center for Microbiome Sciences, this paper examines how environmental exposures shape health disparities. We highlight studies demonstrating that fungal spores, particulate matter, and chemical pollutants disrupt microbiome balance, immune regulation, and metabolic pathways, thereby increasing disease risk in early life and aging populations. The review also considers social determinants of health, spatial inequities, infrastructure vulnerabilities, and policy frameworks that influence exposure and resilience. By integrating environmental epidemiology, microbiome research, and public health policy, this synthesis underscores the urgency of planetary health-informed prevention, surveillance, and management strategies to mitigate pollution-related disease burdens, reduce inequities, and strengthen health in climate-sensitive regions globally.