Cumulative risks predict epigenetic age in adult survivors of extremely low birth weight.

Long-term sequelae of extremely low birth weight (ELBW; ≤1000 g) may contribute to accelerated biological aging. This hypothesis was examined by analyzing a range of risk factors with a molecular age marker in adults born at ELBW or normal birth weight (NBW; ≥2500 g). DNAm age-the weighted average of DNA methylation at 353 cytosine-phosphate-guanine (CpG) sites from across the genome-was derived from a sample of 45 ELBW (M age  = 32.35 years) and 47 NBW control (M age  = 32.44 years) adults, using the Illumina 850k BeadChip Array. At two assessments undertaken 9 years apart (at 23 and 32 years), cumulative risks were summed from six domains with potential to affect physiological and psychological health: resting respiratory sinus arrhythmia, blood pressure, basal cortisol, grip strength, body mass index, and self-esteem. At age 32 years, cumulative risks were differentially associated with epigenetic age in ELBW survivors (interaction, p < 0.01). For each additional risk factor they possessed, ELBW survivors (B = 1.43) were biologically 2.16 years older than NBW adults (B = -0.73), by the fourth decade of life. Developmental change, epigenetic maintenance, and intervention targets are discussed.