Genome-wide DNA methylation in saliva and body size of adolescent girls.

AIM We performed an epigenome-wide association study within the Finnish Health in Teens cohort to identify differential DNA methylation and its association with BMI in adolescents. MATERIALS & METHODS Differential DNA methylation analyses of 3.1 million CpG sites were performed in saliva samples from 50 lean and 50 heavy adolescent girls by genome-wide targeted bisulfite-sequencing. RESULTS We identified 100 CpG sites with p-values < 0.000524, seven regions by 'bumphunting' and five CpG islands that differed significantly between the two groups. The ten CpG sites and regions most strongly associated with BMI substantially overlapped with obesity- and insulin-related genes, including MC2R, IGFBPL1, IP6K1 and IGF2BP1. CONCLUSION Our findings suggest an association between the saliva methylome and BMI in adolescence.