Aging-associated DNA methylation changes in middle-aged individuals: the Young Finns study.

Area of Science:

• Genetics
• Epigenetics
• Gerontology

Background:

• DNA methylation patterns change with chronological aging.
• Previous studies identified aging-associated CpG sites (a-CpGs) but showed limited overlap.
• This study aimed to identify a-CpGs robust to blood cell type heterogeneity.

Purpose of the Study:

• To identify and characterize CpG sites with DNA methylation levels closely related to chronological age in adulthood.
• To determine if these aging-associated changes are consistent regardless of blood cell type.

Main Methods:

• Utilized a multivariable regression model adjusted for blood cell type heterogeneity.
• Analyzed whole blood samples from a narrow age range (40-49 years).
• Compared identified a-CpGs with those from previous studies spanning a wider age range.

Main Results:

• Identified 1202 aging-associated CpG sites (a-CpGs) in middle-aged adults.
• Confirmed previously reported a-CpGs in genes like ELOVL2, FHL2, PENK, and KLF14.
• Found that 987 of the identified a-CpGs were also differentially methylated between nonagenarians and young adults, with identical methylation change directions.

Conclusions:

• Aging-associated DNA methylation features are detectable even in a narrow age range.
• The identified a-CpGs likely represent robust, clock-like aging changes.
• These findings support the concept of consistent epigenetic aging across the adult lifespan.