No association of BDNF methylation with MCI was found in either Uygur or Han Chinese populations.
BDNF methylation levels of male Xinjiang Han MCI cases were higher than male Xinjiang Uygur MCI cases.
BDNF methylation levels were significantly higher in Xinjiang Han Chinese in than Ningbo Han Chinese.
The differences of populations and environments may affect levels of BDNF methylation.