EPIDEMIOLOGICAL ANALYSIS OF NON‑COMMUNICABLE DISEASE BURDEN IN RAPIDLY URBANIZING POPULATIONS

Abstract

Urbanization in low- and middle-income countries has led to an epidemiological transition to non-communicable diseases, but the connections between urban environments and cardiometabolic risk have not been sufficiently measured. The population of this cross-sectional study was 2,187 adults randomly recruited to the study in urban high-density, urban low-density, and rural locations. They calculated a composite urbanization index based on various indicators of the built environment such as population density, availability of road infrastructure, access to sanitation, and access to health facilities. The outcomes were hypertension, type 2 diabetes mellitus, and obesity. Sequential overall sociodemographic and lifestyle factors, mediation analysis to measure pathways using physical inactivity and dietary patterns, and interaction testing by sex and income were conducted using logistic regression. To evaluate the sensitivity to unmeasured confounding, the E-value calculations were performed. The prevalence of hypertension, age-standardized, rose steadily in the rural to urban low-density to urban high-density areas and was about 30 percent to 49 percent. The prevalence of diabetes exhibited the same gradient, with 16 percent to 35 percent in the same categories of urbanicity. In fully adjusted models, every one-standard-deviation increase in the urbanization index was found to increase the odds of hypertension by 47 percent and the odds of diabetes by 53 percent, both of which were highly statistically significant. The mediation analysis indicated that the combination of physical inactivity and unhealthy dietary patterns accounted for 61 percent of the overall urbanization impact on hypertension, with dietary factors taking the bigger portion, which was about 43 percent. There was a strong sex interaction as females exhibited considerably greater risk increases in hypertension associated with urbanization than males did. The effect of processed food on metabolism and fasting glucose was increased in urban areas, as the slope of association increased more than two times between rural and urban high-density areas. The e-values greater than 2.2 in all primary results revealed that unmeasured confounding is unlikely to be the reason behind the observed association. Sensitivity analyses that eliminated the participants that had pre-existing cardiovascular disease generated low attenuation of effect estimates, eliminating reverse causality. The impact of urbanization on non-communicable disease risk is dose-dependent, and more than half of its impact is mediated by modifiable lifestyle behaviors. There is an urgent need for urban planning intervention that encourages physical activity by supporting the existence of walkable infrastructure and food environment regulation by limiting access to processed foods. Special consideration of sex-specific vulnerabilities, particularly in females in high-density cities, is justified to reduce the increasing burden of hypertension, diabetes, and obesity in rapidly urbanizing communities.