(HealthDay News) — For adults of European origin, increased body mass index (BMI) is associated with methylation at three sites in intron 1 of HIF3A, according to a study published online March 13 in The Lancet.
Katherine J. Dick, PhD, from the University of Leicester in the United Kingdom, and colleagues conducted a genome-wide analysis of methylation at CpG sites in relation to BMI. A discovery cohort comprising 459 individuals of European origin underwent methylation level testing. Methylation sites showing an association with BMI were taken forward for replication in a cohort of 339 white patients of northern European origin. Sites that remained significant were tested in a second replication cohort comprising 1,789 white patients of European origin. The correlation between methylation levels at identified sites with BMI was assessed in DNA from adipose tissue and skin from white females (635 and 395 samples, respectively).
The researchers observed an association between methylation at five probes across three genes and BMI. The associations with three of these probes (cg22891070, cg27146050, and cg16672562) located in intron 1 of HIF3A were confirmed in the primary and secondary replication cohorts. Methylation at cg22891070 correlated with BMI in adipose tissue but not in skin.
“Increased BMI in adults of European origin is associated with increased methylation at the HIF3A locus in blood cells and in adipose tissue,” the authors write.