D22-17 Evolving Determinants of Lower Respiratory Infection Burden: A Global Analysis of Social, Environmental, Lifestyle, and Physiological Factors

Background Lower respiratory infections (LRIs) remain a major cause of morbidity and mortality worldwide, despite remarkable improvements in healthcare, nutrition, and vaccination over the past three decades. From 1990 to 2021, the overall global burden of LRIs has declined, yet substantial disparities persist between regions and population groups. During this period, traditional risk factors such as malnutrition and poor sanitation have gradually declined in importance, while emerging determinants—including air pollution, social inequality, aging, and chronic comorbidities—have gained prominence. To comprehensively evaluate these evolving influences, this study integrated multidimensional global data to explore how social, environmental, lifestyle, and physiological factors collectively shape LRI prevalence and mortality. Methods Data from 18 global databases—including the Global Burden of Disease Study, World Health Organization, and World Bank—were combined to construct an extensive dataset covering four domains: socioeconomic and environmental indicators, lifestyle and dietary factors, physiological metrics, and LRI outcomes. Generalized linear regression models were applied to assess associations between cumulative and immediate exposures to these factors and LRI burden. Spearman correlation analysis was further conducted to evaluate interrelationships among the influencing variables. Results The study incorporated 87 social and environmental variables, 178 lifestyle and dietary factors, and 32 physiological indicators. Cumulative exposure analysis revealed that social inequality metrics (e.g., Inequality-Adjusted Human Development Index [IHDI], Gender Inequality Index [GII], and Human Development Index [HDI]), lifestyle factors (e.g., gas cooking and newborn care), and physiological indicators (e.g., uncontrolled hypertension and low bone mineral density) were significantly associated with LRI prevalence. Moreover, social inequality metrics (IHDI, GII) and dietary factors (e.g., vegetable and grain consumption) exhibited strong associations with LRI mortality. Conclusions This study highlights the complex and interconnected roles of social, dietary, lifestyle, and physiological factors in influencing global LRI prevalence and mortality. These findings underscore the importance of integrated public health strategies that address social inequities, promote healthy behaviors, and strengthen healthcare systems to further reduce the worldwide burden of lower respiratory infections.