Diet and dementia worldwide: the role of meat fat, meat protein, and development indicators

Background: Dementia incidence is rising globally, yet its determinants remain debated. While diet has been linked to cognitive health, distinguishing dietary effects from socioeconomic and demographic transitions is challenging. This study examined associations between meat protein and fat supply and dementia incidence worldwide, accounting for life expectancy, GDP per capita, urbanization, and genetic predisposition (Ibs). Methods: Ecological data from 204 “countries” were analyzed. Pearson and Spearman correlations assessed bivariate relationships. Stepwise regression identified independent predictors of dementia incidence (ln-transformed). Partial correlations tested unique effects of protein and fat after adjustment for confounders. Principal component analysis (PCA) explored latent structures. Results: Meat protein and fat supply correlated moderately with dementia incidence (r ≈ 0.65, p < 0.001), but life expectancy showed the strongest association (r = 0.82, p < 0.001). Regression confirmed life expectancy as the dominant correlate (β ≈ 0.56–0.82, p < 0.001). Meat fat supply remained an independent positive association (β = 0.17–0.23, p ≤ 0.01; partial r = 0.22, p = 0.004), whereas protein effects were weaker and inconsistent, sometimes reversing to a negative association (partial r = −0.15, p = 0.043). PCA showed all variables loaded on a single “development–nutrition transition” factor explaining ~74% of variance. Conclusions: Dementia incidence is largely shaped by demographic aging, but dietary fat from meat shows a modest, independent association, whereas protein does not consistently relate to risk. Rising fat consumption linked to nutrition transitions may represent a modifiable global correlate of dementia.