APOE and Alzheimer disease: In two case-control studies conducted in Chinese populations, one including 318 individuals with AD and 324 controls [37], and the other 341 individuals with AD and 421 controls [38], the −572 G allele as well as the −572 GG genotype in the promoter region of the IL-6 gene were associated with a decreased risk for AD; in the second study this association was only present in APOE ε4 allele carriers [38].