Advanced Healthcare Services Leading to Relax Natural Selection May Have Been Contributing to Global and Regional Increase of Dementia Incidence

Abstract BackgroundAgeing and genetic traits can only explain the increasing dementia incidence partially. Advanced healthcare services allowing dementia patients to survive natural selection (die of dementia) and pass their genes onto their next generation. MethodsCountry-specific estimates of dementia incidence rates (all ages and 15-49 years old), Biology State Index (Is) expressing reduced natural selection, ageing indexed by life expectancy e(65), GDP PPP and urbanization were obtained for analysing the global and regional correlations between reduced natural selection and dementia incidence rate with SPSS v. 27. Results Worldwide, both Is significantly, but inversely, correlated to dementia incidence rates for both populations in bivariate correlations. These relationships remained in the populations of all ages and 15-49 years old regardless of the competing contributing effects from ageing, GDP and urbanization in partial correlation model. Enter multiple linear regression showed that Is was the significant predictor of dementia incidence in populations of all ages and 15-49 years old. Subsequently, Is was selected as the variable having the greatest influence on dementia incidence in stepwise multiple linear regression. Is corelated to dementia incidence more strongly in developed population groupings. ConclusionsWorldwide, reduced natural selection may be another the significant contributor to the increasing dementia incidence with special regard to developed population.