Obesity Abstracts

Background: The associations between early life factors and obesity in later life may be mediated through epigenetic mechanisms such as DNA methylation. Infancy rapid weight gain (RWG) is one early life factor that has been consistently associated with increased risk of obesity in childhood. We investigated if early life rapid weight gain (+0.67SD change in weight for age z-score from birth to 1 year), was associated with variation in DNA methylation in childhood and adulthood.

Methods: An epigenome-wide association study was run using Illumina 450K array data from the Avon Longitudinal Study of Parents and Children (ALSPAC), examining early life rapid weight gain (RWG) and blood methylation (in childhood and late adolescence) at individual CpG loci. RWG was associated with a 1% increase in methylation at an individual CpG loci (cg11531579) in childhood (age 7, n=116) in ALSPAC (Bonferroni corrected for multiple comparisons).

The significant CpG (cg11531579) was investigated further in an older population to examine whether the associated variation in blood methylation persisted into adulthood, using the Newcastle Thousand Families study (age 50, n=134). Combined bisulphite modification and pyrosequencing was used to assess DNA methylation.

Results: RWG was also associated with methylation changes in an adult population, although in adults this was a decrease in methylation (−2%, age 50) for those who had RWG in infancy (age 60, n=91).

Conclusion: This study identified that RWG in infancy is associated with small variations in methylation. The loci was positively associated with blood methylation in childhood but negatively in adulthood, The findings may suggest it is an irregular, dynamic, RWG-related loci.

Keywords: DNA methylation, epigenetics, rapid weight gain, life-course