Background: The relationship between mitochondrial DNA copy number (mtDNA CN) and cardiovascular disease remains elusive. Methods and Results: We performed cross‐sectional and prospective association analyses of blood‐derived mtDNA CN and cardiovascular disease outcomes in 27 316 participants in 8 cohorts of multiple racial and ethnic groups with whole‐genome sequencing. We also performed Mendelian randomization to explore causal relationships of mtDNA CN with coronary heart disease (CHD) and cardiometabolic risk factors (obesity, diabetes, hypertension, and hyperlipidemia). P <0.01 was used for significance. We validated most of the previously reported associations between mtDNA CN and cardiovascular disease outcomes. For example, 1‐SD unit lower level of mtDNA CN was associated with 1.08 (95% CI, 1.04–1.12; P <0.001) times the hazard for developing incident CHD, adjusting for covariates. Mendelian randomization analyses showed no causal effect from a lower level of mtDNA CN to a higher CHD risk (β=0.091; P =0.11) or in the reverse direction (β=−0.012; P =0.076). Additional bidirectional Mendelian randomization analyses revealed that low‐density lipoprotein cholesterol had a causal effect on mtDNA CN (β=−0.084; P <0.001), but the reverse direction was not significant ( P =0.059). No causal associations were observed between mtDNA CN and obesity, diabetes, and hypertension, in either direction. Multivariable Mendelian randomization analyses showed no causal effect of CHD on mtDNA CN, controlling for low‐density lipoprotein cholesterol level ( P =0.52), whereas there was a strong direct causal effect of higher low‐density lipoprotein cholesterol on lower mtDNA CN, adjusting for CHD status (β=−0.092; P <0.001). Conclusions: Our findings indicate that high low‐density lipoprotein cholesterol may underlie the complex relationships between mtDNA CN and vascular atherosclerosis.

Background: Although some neuropsychological (NP) tests are considered more central for the diagnosis of Alzheimer disease (AD), there is a lack of understanding about the interaction between different cognitive tests. Objective: This study aimed to demonstrate a global view of hierarchical probabilistic dependencies between NP tests and the likelihood of cognitive impairment to assist physicians in recognizing AD precursors. Methods: Our study included 2091 participants from the Framingham Heart Study. These participants had undergone a variety of NP tests, including Wechsler Memory Scale, Wechsler Adult Intelligence Scale, and Boston Naming Test. Heterogeneous cognitive Bayesian networks were developed to understand the relationship between NP tests and the cognitive status. The performance of probabilistic inference was evaluated by the 10-fold cross validation. Results: A total of 4512 NP tests were used to build the Bayesian network for the dementia diagnosis. The network demonstrated conditional dependency between different cognitive functions that precede the development of dementia. The prediction model reached an accuracy of 82.24%, with sensitivity of 63.98% and specificity of 92.74%. This probabilistic diagnostic system can also be applied to participants that exhibit more heterogeneous profiles or with missing responses for some NP tests. Conclusions: We developed a probabilistic dependency network for AD diagnosis from 11 NP tests. Our study revealed important psychological functional segregations and precursor evidence of AD development and heterogeneity.

Aims: We tested the hypothesis that mitochondrial DNA copy number (CN) is associated with cardiometabolic disease (CMD) traits. Methods and results: We determined the cross-sectional association of mtDNA CN measured in whole blood with several CMD traits in 65,996 individuals (mean age 60, 54% women, and 79% European descent). Cohort- and ancestry/ethnicity-specific association analysis was performed adjusting for trait- and cohort-specific covariates. Age was slightly positively associated with age (0.03 s.d. / 10 years (95% CI=0.01, 0.05)) before 65 years, while every 10 years older age was associated with 0.14 s.d. lower level of mtDNA CN after 65 years (95% CI= -0.18, -0.10). In meta-analysis without adjustment for white blood cell (WBC) and differential count in participants of European descent (N=52,491), low mtDNA CN was associated with increased odds of obesity (OR with 95% CI=1.13 (1.11, 1.16), P=3.3e-30) and hypertension (OR=1.05 (1.03, 1.08), P=4.0e-07). Further adjusting for WBC and differential count in the same participants of European descent (N=44,035), associations became non-significant (P>0.05) for hypertension, attenuated for obesity (OR _{without cell count} =1.15 (1.12, 1.18) versus OR _{cell count} =1.06 (1.03, 1.08)) but strengthened for hyperlipidemia (OR _{without cell counts} =1.03 (1.00, 1.06) versus OR _{cell counts} =1.06 (1.03, 1.09)). The magnitude and directionality of most associations were consistent between participants of European descent and other ethnicity/ancestry origins. Conclusion: Low levels of mtDNA CN in peripheral blood were associated with an increased risk of CMD diseases.

Investigating the interplay between mitochondrial DNA (mtDNA) variations and epigenetic aging metrics may elucidate biological mechanisms associated with age‐related diseases. We estimated epigenetic age acceleration (EAA) metrics from DNA methylation data and derived mtDNA metrics, including heteroplasmic variants and mtDNA copy number (mtDNA CN) from whole genome sequencing. Linear regressions and meta‐analyses were conducted to assess associations between EAA and mtDNA metrics, adjusting for chronological age, self‐identified sex, and other covariates in 6,316 participants (58% female, 41% non‐White Americans). Mediation analysis was conducted to examine whether EAA mediated the relationship between mtDNA CN and metabolic traits. A higher burden of rare heteroplasmic variants was associated with accelerations of first‐generation EAA metrics, while a lower level mtDNA CN was associated with accelerations of second‐ and third‐generation EAA metrics. For example, one standard deviation (SD) higher MSS, a score based on the predicted functions of rare heteroplasmic variants, was associated with a 0.22‐year higher EAA by the Hannum method ( p = 1.3E‐6) among all participants, while one SD lower mtDNA CN was associated with higher DunedinPACE ( β = −0.005, p = 6.0E‐4). No significant association was observed between the heteroplasmy burden of common variants and EAAs. Furthermore, we observed DunedinPACE mediated 11.1% and 10.8% of the associations of mtDNA CN with obesity and T2DM in older FHS participants, respectively. Our analysis indicated that higher levels of heteroplasmy burden of rare variants and lower mtDNA CN were associated with accelerated epigenetic aging, and these associations showed stronger magnitudes among older participants.

Background: Alcohol use patterns influence health outcomes. This study examined sex-specific drinking trajectories and their associations with all-cause mortality and coronary heart disease (CHD) in the US-based Framingham Heart Study. Method: Among 6570 participants (mean age: 55 ± 13; 55% women) followed for 15 years, a growth mixture model identified four sex-specific alcohol consumption trajectories. Cox models examined associations of alcohol trajectories with CHD and mortality over 10 years of follow-up, adjusting for covariates. Results: This study identified four distinct, sex-specific alcohol consumption trajectories: the Moderate-Decreasing group (1179 women, 0–14 g/day; 1534 men, 0–28 g/day) showed a declining moderate intake, The Low-to-None group included light or non-drinkers (992 women, 826 men), the Inverse-U group (606 women, 199 men) showed variable intake over time, while the High-Decreasing group (858 women, 376 men) had high initial consumption (women > 14 and men > 28 g/day) that declined over time. Compared with the Moderate-Decreasing group, women in other groups had higher CHD risks (HRs 1.58–1.61) and greater mortality risk in the Low-to-None (HR 1.25) and Inverse-U (HR 1.28) groups. Men in Low-to-None had higher mortality (HR 1.17) and CHD (HR 1.60), while High-Decreasing showed the highest mortality (HR 1.27). Low-to-moderate drinking was associated with lower mortality and CHD risks; however, these findings do not confirm the protective effects of alcohol use. Discussion: Our findings suggest that sustained low to moderate drinking was associated with lower risks of mortality and CHD in both women and men, compared to high-level or fluctuating patterns. Although these associations may not confirm causality, our findings emphasize the importance of investigating long-term drinking patterns in public health. Nevertheless, we caution against promoting moderate alcohol use as a strategy to reduce mortality risk or prevent CHD.

We analyze 10,986 participants (mean age 77; 63% women; 54% non-White) across seven U.S. cohorts to study the relationship between mitochondrial DNA (mtDNA) heteroplasmy and nuclear DNA methylation. We identify 597 CpGs associated with heteroplasmy burden, generally showing lower methylation. These CpGs are enriched in dynamically regulated island shores and depleted in CpG islands, indicating involvement in context-specific rather than constitutive gene regulation. In HEK293T cells, we introduce a truncating mtDNA mutation (MT-COX3, mt.9979) and observe a positive correlation between variant allele fraction and methylation at cg04569152, supporting a direct mtDNA–nDNA epigenetic link. Many heteroplasmy-associated CpGs overlap with known methylation-trait associations for metabolic and behavioral traits. Composite CpG scores predict all-cause mortality and incident CVD, with one-unit increases associated with 1.27-fold and 1.12-fold higher hazards, respectively. These findings suggest an mtDNA–nDNA epigenetic connection in aging and disease, though its direction and mechanisms remain to be studied.