Fox, 2014 
Spring Valley Community, Washington, District of Columbia. Spring Valley was built on a chemical weapons lab which caused arsenic to be distributed to the surface soil.
Population of Spring Valley 2006 – 2010: 24,762
Comparison of annual average age-adjusted mortality rates (per 100,000) between Spring Valley, Chevy Chase (2004 – 2010) and the US (2007). No measure of arsenic concentration is given for these areas at these times.
AD mortality rate in Spring Valley (22.8; CI 20.3 – 25.4) was comparable to the Chevy Chase (22; CI 19 – 25) and US (24.70) rates. No statistically significant difference.
Dani, 2010 
Secondary analysis of country-level data.
Slight increases in arsenic concentration in soil were related to exponential increases in dementia rates at a country level.
Emard et al., 1994 
The IMAGE Project covering the population of Saguenay-Lac-Saint-Jean (SLSJ), Québec.
129 individuals with AD (clinically diagnosed by standard medical services) who were born in SLSJ.
Cross-sectional study: principal components analysis. Samples of aquatic sediment were analysed for geochemical variables. AD cases were identified from a registry.
15 individuals with AD were born in areas with lower than average concentration of lead; 49 were born in areas with higher than average concentrations. This difference was statistically significant (P < 0.05).