Alzheimer's disease is extremely infamous due to its induced progressive loss of brain cells that leads to memory loss and the impairment of other thinking skills. The pathogenesis of Alzheimer's disease is extremely complex. Here is an estimate of how the disease is prevalent among us humans:
Image labeled for reuse on Google, via https://www.cdc.gov/aging/data/pdf/american-alzheimers-racial-ethnic-disparities-infographic-508-h.pdf
The previous diagram demonstrates the racial and ethnic disparities of Americans suffering from Alzheimer's Disease and related dementias.