The cardiometabolic ageing–cardiovascular disease axis: A 32-year European study

Background: Cardiometabolic ageing encompasses the population-level coexistence of diabetes, obesity, and demographic ageing within the analytical framework of this study. We examined whether this profile, summarized by a Diabetes–Obesity–Ageing (DOA) index, was associated with cardiovascular disease (CVD) burden and whether this association varied with national income. Methods: We analysed a balanced panel of 27 European Union countries from 1990 to 2021. DOA was calculated as the equally weighted mean of pooled z-scores for age-standardized diabetes prevalence, age-standardized obesity prevalence, and the proportion aged ≥65 years. The ageing component represented demographic composition. Two-way fixed-effects models examined associations with age-standardized CVD disability-adjusted life-year and mortality rates, including an interaction between DOA and ln(GDP per capita). Sensitivity analyses included alternative estimators, temporal specifications, component-specific models, and PCA-based weighting. Results: The DOA × ln(GDP) interaction was negative and statistically significant in the primary model (β = −0.111; p = 0.006), with a consistent result for cardiovascular mortality (β = −0.118; p = 0.004). Component-specific interactions were significant for diabetes and population ageing, but not obesity. The PCA-based interaction was also negative and significant. Temporal analyses showed a negative interaction in levels models and a positive interaction in short-run specifications. Lead-placebo associations were also significant, while cointegration tests provided mixed evidence of a stable long-run relationship. Conclusions: Higher national income was associated with attenuation of the DOA–CVD relationship in levels models. The composite and component-specific analyses provide complementary perspectives on this pattern, with clearer evidence for diabetes and population ageing. These findings describe an income-dependent population-level association whose interpretation remains sensitive to temporal specification.