A new study published in Psychology and Aging reports that loneliness may accelerate biological aging and exacerbate chronic health conditions in older adults.
Loneliness is a growing public health concern. Previous research has linked loneliness to a range of health issues, including cardiovascular, inflammatory, and metabolic conditions, as well as overall increased mortality. However, these associations do not account for all the health risks related to loneliness.
The concept of epigenetic aging, where biological age differs from chronological age due to molecular changes in DNA, is a promising area for understanding these risks. In this study, researchers Colin D. Freilich and colleagues investigated whether loneliness is associated with accelerated epigenetic aging and whether this, in turn, impacts chronic health conditions.
The researchers utilized data from the Midlife Development in the United States (MIDUS) study, a comprehensive, longitudinal study that examines the role of psychological, social, and biological factors in aging. A total of 445 participants (between ages 26-86) who had completed longitudinal follow-ups were included in the analyses.
Loneliness was measured at the initial time point using three self-report items, with participants indicating how much of the time in the past 30 days they felt lonely, close to others, and like they belonged, on a 5-point scale. At two subsequent time points, participants reported any of 30 chronic health conditions they had experienced or been treated for in the past 12 months.
Epigenetic age acceleration (EAA) was measured using several epigenetic clocks derived from DNA methylation profiles obtained from blood samples. The clocks included the Horvath, DunedinPACE, and GrimAge measures, which estimate biological age based on DNA methylation patterns. The DNA samples were collected, frozen, and subjected to genome-wide methylation profiling using Illumina Methylation EPIC microarrays.
The researchers found that greater loneliness was weakly associated with greater EAA across different measures after accounting for demographic and behavioral covariates. This indicates that individuals who reported higher levels of loneliness also exhibited greater biological aging as measured by the Horvath, DunedinPACE, and GrimAge epigenetic clocks.
Loneliness also predicted increases in the number of chronic health conditions over time. The effect of loneliness on chronic health conditions was more pronounced in individuals with higher DunedinPACE EAA values, suggesting a possible synergistic effect. While EAA was associated with both loneliness and health outcomes, it did not fully explain the relationship between them, highlighting the direct impact of loneliness on health.
A limitation outlined by the authors is the reliance on self-reported measures for loneliness and chronic health conditions, which can be subject to biases and inaccuracies.
The study, “Loneliness, Epigenetic Age Acceleration, and Chronic Health Conditions,” was authored by Colin D. Freilich, Kristian E. Markon, Steve W. Cole, and Robert F. Krueger.
