“…Seven studies analyzed global DNA methylation [6,7,23,34,36,42,52], 31 followed a candidate-gene approach [8][9][10][11][12][13][14]20,22,[24][25][26][27][28][29][30][31][32][33]35,[38][39][40][41]45,46,49,50,[54][55][56], seven were epigenome-wide association studies (EWAS) [16,18,19,21,44,48,53], two used both global DNA methylation and candidate-gene approaches [37,43], three used EWAS and global DNA methylation approaches [15,17,51], and on...…”