Age at the visit was negatively associated with Alu element methylation (β = −0.12 % 5 mC/year, p = 0.0005). A weaker association was observed with LINE-1 elements (β = −0.06 % 5 mC/year, p = 0.049). We observed a significant decrease in average Alu methylation over time, with a −0.2 % 5 mC change (p = 0.012) compared to blood samples collected up to 8 years earlier. The longitudinal decline in Alu methylation was linear and highly correlated with time since the first measurement (β = −0.089 % 5 mC/year, p < 0.0001). In contrast, average LINE-1 methylation did not vary over time [p = 0.51]. Our results demonstrate a progressive loss of DNA methylation in repetitive elements dispersed throughout the genome.