Animal protein supply, cognitive ageing and female–male dementia disparities: a global ecological analysis

Aim: Population-level evidence linking animal protein supply with dementia incidence remains limited. This study examined global associations between national animal protein supply and dementia incidence within an ecological framework of nutritional and epidemiological transition.Materials & methods: Harmonized population-level data from the Food and Agriculture Organization of the United Nations statistical database (FAOSTAT), the Institute for Health Metrics and Evaluation (IHME), the World Bank, the World Health Organization (WHO) and United Nations data platforms were analyzed for up to 204 populations. Animal protein supply was examined in relation to total dementia incidence and female–male differences in dementia incidence using correlation analysis, partial correlation, polynomial modeling, principal component analysis, multivariable regression and stratified analyses by income, development and regional groupings.Results: Animal protein supply was positively associated with total dementia incidence. Associations were non-linear, with steeper increases at low-to-moderate supply levels and attenuation at the highest levels. Associations were stronger in low- and middle-income and developing settings than in high-income or developed contexts. Animal protein supply remained positively associated with female–male incidence differences after adjustment; independence from total incidence and mediation through it were not directly tested.Conclusion: Animal protein supply may operate as an ecological marker of nutritional and epidemiological transition rather than as an isolated dietary exposure. These findings support context-sensitive interpretation of diet–dementia associations in global cognitive ageing research.