Summary: Researchers identify five biological markers that together reveal important influences on biological aging.
Source: eLife
A composite biological-age score indicates that male sex, higher body weight, smoking and depression are associated with accelerated biological aging, a study published today in eLife reports.
Chronological age is simply the number of years since birth, but biological age attempts to capture how well the body is functioning relative to that number. Scientists measure biological aging in multiple ways, including the length of telomeres (the protective caps at the ends of chromosomes that tend to shorten with age), DNA chemical modifications (epigenetic markers), and shifts in the proteins and small molecules circulating in the blood (proteomic and metabolomic profiles). Each approach offers a window into different cellular processes that change as we grow older.
Although prior research has linked individual aging measures to physical and mental health, less is known about how these measures relate to one another and whether combining them provides a clearer picture of overall biological aging. This new study is the first to integrate five commonly used biological-age measures and examine how they jointly associate with mental and physical health indicators.
“To better understand mechanisms underlying biological aging, we set out to compare how different aging indicators relate to each other, how they connect to lifestyle and health factors, and whether a combined biological clock offers improved prediction of health,” explains Rick Jansen, Assistant Professor at the Department of Psychiatry, Amsterdam UMC, and lead author of the study.
The research team analyzed blood samples from nearly 3,000 participants in the Netherlands Study of Depression and Anxiety. Using statistical modeling, they generated individual biological-age estimates from five molecular approaches: telomere length, epigenetic markers, transcriptomics (gene expression), proteomics (protein profiles), and metabolomics (small molecule profiles). Each of these biological clocks was then examined in relation to demographic characteristics, lifestyle behaviors and diagnosed conditions, including depression and metabolic disorders.
The investigators found that only three of the five indicators showed meaningful associations with one another in the same individuals, indicating that many aspects of molecular aging act independently. Still, certain risk factors consistently correlated with more advanced biological age. Male sex, higher body mass index (BMI), current smoking and the presence of metabolic syndrome were most reliably linked to accelerated biological aging across the measures examined.
Depression was also associated with more advanced aging for several molecular clocks, specifically those based on epigenetic markers, gene expression patterns and protein profiles. These links indicate that mental health conditions such as depression can be reflected in biological systems that relate to aging.
When the researchers combined all five biological-age measures into a single composite score, associations with health and lifestyle factors became stronger and more numerous than for any individual clock alone. The composite score showed particularly robust relationships with BMI, sex, smoking, depression severity and metabolic syndrome. This suggests that combining multiple molecular signals yields a more comprehensive measure of cumulative biological aging than any single approach.
“Our findings suggest that different biological aging indicators capture largely distinct, though partially overlapping, facets of the aging process,” concludes Brenda Penninx, Professor of Psychiatric Epidemiology at Amsterdam UMC and senior author on the paper. “Taken together, these results improve our understanding of what determines biological age and will help guide the development of outcomes for clinical studies and population research.”
About this aging research news
Source: eLife
Contact: Emily Packer – eLife
Image: The image is in the public domain
Original Research: Open access.
Title: “An integrative study of five biological clocks in somatic and mental health” by Rick Jansen, Laura KM Han, Josine E Verhoeven, Karolina A Aberg, Edwin CGJ van den Oord, Yuri Milaneschi, Brenda WJH Penninx. eLife
Abstract
An integrative study of five biological clocks in somatic and mental health
Biological clocks have been developed at multiple molecular levels and are often more advanced in the presence of physical illness and mental disorders. Still, it remains unclear whether different clocks reflect the same aging processes and share common determinants. In roughly 3,000 participants, we evaluated five biological clocks—telomere length, epigenetic, transcriptomic, proteomic and metabolomic—and tested how they relate to one another and to somatic and mental health factors. Correlations between the individual aging indicators were small (all r < 0.2), indicating limited overlap. The most consistent predictors of advanced biological aging were male sex, higher BMI, metabolic syndrome, smoking and depression. Compared with single clocks, a composite index combining all five clocks showed the strongest associations with health determinants. The large effect sizes for the composite index, together with the low intercorrelations among individual clocks, suggest that an individual’s biological age is best estimated by integrating aging measures from several molecular levels.