DNA methylation (DNAm) algorithms of biological age provide a robust estimate of an individual’s chronological age, and can predict of their risk of age-related disease and mortality. This study reviewed the evidence that environmental, lifestyle and health factors are associated with the Horvath and Hannum epigenetic clocks. A systematic search identified 61 studies. Chronological age was correlated with DNAm age in blood (median 0.83, range 0.13-0.99). DNAm age was positively associated with frailty (three studies, n=3,093), and education was negatively associated with the Hannum estimate of DNAm age specifically (four studies, n=13,955). For most other exposures, findings were too inconsistent to draw conclusions. In a meta-analysis BMI was associated with increased DNAm age (Hannum β: 0.07, 95%CI 0.04 to 0.10; Horvath β:0.06, 95%CI 0.02 to 0.10), but there was no association with smoking (Hannum β:0.12, 95%CI -0.50 to 0.73; Horvath β:0.18, 95%CI -0.10 to 0.46). In conclusion, BMI were positively associated with biological ageing measured using DNAm, with some evidence that frailty also increased ageing. More research is needed to provide conclusive evidence regarding other exposures. This field of research has the potential to provide further insights into how to promote slower biological aging and ultimately prolong healthy life.
|Number of pages||60|
|Journal||Journal of Gerontology Series A: Biological Sciences and Medical Sciences|
|Publication status||Accepted/In press - 17 Apr 2019|
Ryan, J., Wrigglesworth, J., Loong, J., Fransquet, P. D., & Woods, R. (Accepted/In press). A systematic review and meta-analysis of environmental, lifestyle and health factors associated with DNA methylation age. Journal of Gerontology Series A: Biological Sciences and Medical Sciences. https://doi.org/10.1093/gerona/glz099