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Growing evidence has linked inflammatory processes to cognitive decline and dementia. This work examines whether an epigenetic marker of C-reactive protein (CRP), a common clinical inflammatory biomarker, may mediate the relationship between educational attainment and cognition. We first evaluated whether 53 previously reported CRP-associated DNA methylation sites (CpGs) are associated with CRP, both individually and aggregated into a methylation risk score (MRSCRP), in 3 298 participants from the Health and Retirement Study (HRS, mean age = 69.7 years). Forty-nine CpGs (92%) were associated with the natural logarithm of CRP in HRS after adjusting for age, sex, smoking, BMI, genetic ancestry, and white blood cell counts (p  < .05), and each standard deviation increase in MRSCRP was associated with a 0.38 unit increase in lnCRP (p  = 4.02E-99). In cross-sectional analysis, for each standard deviation increase in MRSCRP, total memory score and total cognitive score decreased, on average, by 0.28 words and 0.43 items, respectively (p  < .001). Further, MRSCRP mediated 6.9% of the relationship between high school education and total memory score in a model adjusting for age, sex, and genetic ancestry (p  < .05); this was attenuated to 2.4% with additional adjustment for marital status, APOE ε4 status, health behaviors, and comorbidities (p  < .05). Thus, CRP-associated methylation may partially mediate the relationship between education and cognition at older ages. Further research is warranted to determine whether DNA methylation at these sites may improve current prediction models for cognitive impairment in older adults. [ABSTRACT FROM AUTHOR]

Background: Dyslipidemia, which is characterized by an unfavorable lipid profile, is a key risk factor for cardiovascular disease (CVD). Understanding the relationships between epigenetic aging and lipid levels may help guide early prevention and treatment efforts for dyslipidemia. Methods: We used weighted linear regression to cross-sectionally investigate the associations between five measures of epigenetic age acceleration estimated from whole blood DNA methylation (HorvathAge Acceleration, HannumAge Acceleration, PhenoAge Acceleration, GrimAge Acceleration, and DunedinPACE) and four blood lipid measures (total cholesterol (TC), LDL-C, HDL-C, and triglycerides (TG)) in 3,813 participants (mean age = 70 years) from the Health and Retirement Study (HRS). As a sensitivity analysis, we examined the same associations in participants who fasted prior to the blood draw (n = 2,531) and in participants who did not take lipid-lowering medication (n = 1,869). Using interaction models, we also examined whether demographic factors including age, sex, and educational attainment modified the relationships between epigenetic age acceleration and blood lipids. Results: After adjusting for age, race/ethnicity, sex, fasting status, and lipid-lowering medication use, greater epigenetic age acceleration was associated with lower TC, HDL-C, and LDL-C, and higher TG (p < 0.05), although the effect sizes were relatively small (e.g., < 7 mg/dL of TC per standard deviation in epigenetic age acceleration). GrimAge acceleration and DunedinPACE associations with all lipids remained significant after further adjustment for body mass index, smoking status, and educational attainment. These associations were stronger in participants who fasted and who did not use lipid-lowering medication, particularly for LDL-C. We observed the largest number of interactions between DunedinPACE and demographic factors, where the associations with lipids were stronger in younger participants, females, and those with higher educational attainment. Conclusion: Multiple measures of epigenetic age acceleration are associated with blood lipid levels in older adults. A greater understanding of how these associations differ across demographic groups can help shed light on the relationships between aging and downstream cardiovascular diseases. The inverse associations between epigenetic age and TC and LDL-C could be due to sample limitations or non-linear relationships between age and these lipids, as both TC and LDL-C decrease faster at older ages. [ABSTRACT FROM AUTHOR]

Biomarkers developed from DNA methylation (DNAm) data are of growing interest as predictors of health outcomes and mortality in older populations. However, it is unknown how epigenetic aging fits within the context of known socioeconomic and behavioral associations with aging-related health outcomes in a large, population-based, and diverse sample. This study uses data from a representative, panel study of US older adults to examine the relationship between DNAm-based age acceleration measures in the prediction of cross-sectional and longitudinal health outcomes and mortality. We examine whether recent improvements to these scores, using principal component (PC)-based measures designed to remove some of the technical noise and unreliability in measurement, improve the predictive capability of these measures. We also examine how well DNAm-based measures perform against well-known predictors of health outcomes such as demographics, SES, and health behaviors. In our sample, age acceleration calculated using “second and third generation clocks,” PhenoAge, GrimAge, and DunedinPACE, is consistently a significant predictor of health outcomes including cross-sectional cognitive dysfunction, functional limitations and chronic conditions assessed 2 y after DNAm measurement, and 4-y mortality. PC-based epigenetic age acceleration measures do not significantly change the relationship of DNAm-based age acceleration measures to health outcomes or mortality compared to earlier versions of these measures. While the usefulness of DNAm-based age acceleration as a predictor of later life health outcomes is quite clear, other factors such as demographics, SES, mental health, and health behaviors remain equally, if not more robust, predictors of later life outcomes. [ABSTRACT FROM AUTHOR]