Table 2.
Comparison of partial correlation coefficients between dementia incidence and each variable when the other three variables were kept statistically constant.
| Variables | r | p | r | p | r | p | r | p |
|---|---|---|---|---|---|---|---|---|
| Dementia incidence rate in populations of all ages | ||||||||
| Is | − 0.429 | < 0.001 | – | – | – | – | – | – |
| Ageing | – | – | 0.278 | < 0.001 | – | – | – | – |
| GDP PPP | – | – | – | – | − 0.018 | 0.800 | – | – |
| Urban | – | – | – | – | – | – | < 0.05 | 0.763 |
| Dementia incidence rate in population segments of 15–49 years old | ||||||||
| Is | − 0.452 | < 0.001 | – | – | – | – | – | – |
| Ageing* | NA | NA | NA | NA | NA | NA | NA | NA |
| GDP PPP | – | – | – | – | − 0.160 | < 0.05 | – | – |
| Urban | – | – | – | – | – | – | < 0.01 | 0.912 |
Significance level: *p < 0.05; **p < 0.01; ***p < 0.001; sample size range: 170 for all analyses.
Data sources: Dementia Incidence expressed as the number of new onsets of Alzheimer's disease and other dementias published by the Institute for Health Metrics and Evaluation (IHME) in 2020; Is measuring the magnitude of the opportunity for natural selection, extracted from the previous publication by You et al. https://doi.org/10.1111/eva.12523; Ageing expressed with life expectancy at 65 years old (2010–2015) published by the United Nations; GDP PPP expressed in purchasing power parity in 2015 US dollars published by the World Bank; Urbanization expressed in percent of population living in urban areas in 2015 published by the World Bank.