Cohort Profile: The Nanjing Chronic Disease Cohort

As a major global public health threat, non-communicable diseases (NCDs), such as cardiovascular disease, cancer, chronic respiratory disorder, and diabetes mellitus, are characterized by high treatment expenditures, poor prognosis, and substantial societal burdens [1–3]. Annually, NCDs account for ∼41 million deaths, equivalent to 74% of global mortality [4]. In China, the mortality rate from NCDs increased from 534.6 to 748.0 per 100 000 people from 1990 to 2021 will continue to increase in the near future [5]. Notably, the incidence of multimorbidity—the coexistence of two or more NCDs within an individual—has been steadily increasing in China, contributing to elevated mortality rates, reduced quality of life, and heightened strain on healthcare resources [6–8]. The mechanisms and outcomes of multimorbidity vary across disease clusters but remain poorly understood [9, 10]. Prospective evidence elucidating modifiable drivers of multimorbidity is critically required to inform the targeted prevention frameworks and evidence-based management paradigms for this public health challenge.