Hypothesis

Disruption of circadian‑driven chromatin remodeling accelerates epigenetic aging, particularly in females during the perimenopausal transition, and restoring circadian chromatin dynamics via timed NAD⁺ boosting will reduce biological age predictions in multi‑omics digital twin models.

Rationale

Recent work shows that multi‑omics clocks outperform single‑omics predictors and reveal sex‑specific aging trajectories, with women exhibiting a sharp acceleration in their fifth decade that coincides with menopause [4]. Parallel studies demonstrate that circadian regulators (e.g., BMAL1, CLOCK) control rhythmic histone acetylation and methylation, linking temporal gene expression to epigenetic age [7]. Moreover, NAD⁺ levels decline with age and modulate sirtuin activity, which deacetylates histones in a circadian‑dependent manner.

We hypothesize that the menopausal drop in estrogen reduces BMAL1 expression in peripheral tissues, dampening circadian chromatin remodeling. This leads to a loss of rhythmic histone marks, causing a drift toward a higher epigenetic age as captured by multi‑omics clocks. Consequently, the digital twin’s predicted biological age diverges from chronological age more rapidly in females than males.

Novel Mechanistic Insight

Beyond correlative observations, we propose a causal loop: estrogen‑dependent BMAL1 transcription → circadian histone acetylation cycles → periodic NAD⁺‑dependent SIRT1 activity → controlled heterochromatin‑euchromatin transitions → stable methylation patterns at age‑associated CpG sites. When estrogen falls, BMAL1 amplitude falls, NAD⁺ rhythms flatten, SIRT1 activity becomes constitutively low, resulting in hypoacetylated histones and aberrant DNA methylation at loci driving the OMICmAge acceleration.

Thus, interventions that reinstate circadian NAD⁺ oscillations (e.g., timed nicotinamide riboside supplementation aligned to individual activity rhythms) should restore SIRT1‑mediated deacetylation, re‑establish proper histone mark rhythms, and consequently lower the multi‑omics biological age estimate.

Testable Predictions

1. Longitudinal multi‑omics profiling of pre‑menopausal, perimenopausal, and post‑menopausal women will show a correlation between reduced BMAL1 expression (measured in blood mononuclear cells), flattened NAD⁺ rhythms, loss of daily H3K27ac oscillation, and an increase in OMICmAge residuals beyond what is explained by chronological age alone.
2. Male counterparts will exhibit a milder, age‑graded decline in these circadian markers, consistent with their linear biological age trajectory.
3. Intervention trial: administering NAD⁺ precursors at the individual’s circadian nadir (determined via wearable melatonin or core temperature) for 12 weeks will increase daily H3K27ac amplitude, improve SIRT1 activity, and produce a statistically significant reduction (≥1.5 years) in predicted biological age from the digital twin model compared to placebo or mistimed supplementation.
4. In silico, a digital twin model that incorporates circadian chromatin variables (BMAL1, NAD⁺, SIRT1 activity) will predict the observed sex‑specific aging curves only when these variables are included; removing them will erase the female acceleration phenotype.

Falsifiability

If longitudinal data reveal no association between circadian chromatin markers and OMICmAge acceleration, or if timed NAD⁺ supplementation fails to alter biological age predictions despite restoring NAD⁺ levels, the hypothesis is falsified. Likewise, if adding circadian chromatin variables to the digital twin does not improve prediction of sex‑specific trajectories, the mechanistic claim is unsupported.

Implementation Note

Researchers can leverage existing digital twin platforms (e.g., the OMICmAge framework [3]) and extend them with a circadian module that ingests time‑stamped omics, wearable‑derived activity, and metabolite data to simulate the impact of chronotherapeutic NAD⁺ boosting.

By tying estrogen‑driven circadian chromatin dynamics to epigenetic aging, this hypothesis bridges multi‑omics aging clocks, sex‑specific trajectories, and actionable chronotherapeutic interventions, offering a concrete path to refine digital twin predictions and validate personalized longevity strategies.