Lower birth rate, greater female dementia risk: global and regional patterns and public health implications.

Aims: This study investigates the relationship between national birth rate and female dementia incidence globally, considering demographic and socioeconomic confounders.

Materials & methods: Data from 204 countries were analyzed using bivariate correlation, partial correlation, principal component analysis, and multiple linear regression. Female dementia incidence rate (FDIR) was the dependent variable. Birth rate served as the main predictor, with ageing (life expectancy), genetic predisposition (Biological State Index), economic affluence (GDP PPP), and urban living as confounders.

Results: Birth rate demonstrated a significant inverse correlation with female dementia incidence (Pearson's r = -0.772, p < 0.001), remaining robust after adjusting for confounders (partial r = -0.548, p < 0.001). Stepwise regression confirmed birth rate as the strongest independent predictor, explaining 61.6% of the variance in FDIR. Genetic predisposition and ageing were also significant, while economic affluence and urban living had minimal effects. The inverse relationship was more pronounced in developing countries and low-income regions.

Conclusions: Lower birth rates were strongly associated with higher female dementia incidence globally. Birth rate should be considered a critical demographic factor in dementia risk prediction and public health planning, particularly in ageing and low-resource settings.