graph LR
Respiratory_Epithelial_Infection_and_Cytopathic_Effect["Respiratory Epithelial Infection and Cytopathic Effect"]
Endothelial_Dysfunction_and_Thromboinflammation["Endothelial Dysfunction and Thromboinflammation"]
Immune_competent_microvascularized_lung_on_a_chip_IC_LOC_severe_H1N1_model["Immune-competent microvascularized lung-on-a-chip (IC-LOC) severe H1N1 model"]
Triggering_of_Acute_Myocardial_Infarction["Triggering of Acute Myocardial Infarction"]
Inflammasome_Activation_and_Cytokine_Storm["Inflammasome Activation and Cytokine Storm"]
Endothelial_Dysfunction_and_Thromboinflammation --> Triggering_of_Acute_Myocardial_Infarction
Immune_competent_microvascularized_lung_on_a_chip_IC_LOC_severe_H1N1_model --> Inflammasome_Activation_and_Cytokine_Storm
Immune_competent_microvascularized_lung_on_a_chip_IC_LOC_severe_H1N1_model --> Respiratory_Epithelial_Infection_and_Cytopathic_Effect
Immune_competent_microvascularized_lung_on_a_chip_IC_LOC_severe_H1N1_model --> Endothelial_Dysfunction_and_Thromboinflammation
style Respiratory_Epithelial_Infection_and_Cytopathic_Effect fill:#dbeafe
style Endothelial_Dysfunction_and_Thromboinflammation fill:#dbeafe
style Immune_competent_microvascularized_lung_on_a_chip_IC_LOC_severe_H1N1_model fill:#ccfbf1
style Triggering_of_Acute_Myocardial_Infarction fill:#dbeafe
style Inflammasome_Activation_and_Cytokine_Storm fill:#dbeafe
graph LR
Neuronal_Endosomal_Lysosomal_Acidification_Failure["Neuronal Endosomal-Lysosomal Acidification Failure"]
Glymphatic_Clearance_Failure["Glymphatic Clearance Failure"]
Cumulative_exposure_to_strong_central_anticholinergic_medication["Cumulative exposure to strong central anticholinergic medication"]
Necroptotic_Neuronal_Death["Necroptotic Neuronal Death"]
Senescent_Cell_Accumulation["Senescent Cell Accumulation"]
PYCARD["PYCARD"]
Brain_N_Glycan_Hyperglycosylation["Brain N-Glycan Hyperglycosylation"]
TREM2["TREM2"]
Cortical_Structural_Connectivity_Degeneration["Cortical Structural Connectivity Degeneration"]
Amyloid_Plaque_Formation["Amyloid Plaque Formation"]
Oxidative_Stress["Oxidative Stress"]
PARP1_Mediated_Parthanatos["PARP1-Mediated Parthanatos"]
Tau_Directed_Antisense_Oligonucleotide_Therapy["Tau-Directed Antisense Oligonucleotide Therapy"]
Tau_Induced_Nucleocytoplasmic_Transport_Failure["Tau-Induced Nucleocytoplasmic Transport Failure"]
Selective_Vulnerability_of_RORB+_Entorhinal_Excitatory_Neurons["Selective Vulnerability of RORB+ Entorhinal Excitatory Neurons"]
Intercellular_Tau_Transmission_via_Extracellular_Vesicles["Intercellular Tau Transmission via Extracellular Vesicles"]
Neuroinflammation["Neuroinflammation"]
Interneuron_Dysfunction_and_Network_Hypersynchrony["Interneuron Dysfunction and Network Hypersynchrony"]
LRP1["LRP1"]
HMC3_human_microglial_micro_MKKS63_CRISPR_Cas9_knockout_lines["HMC3 human microglial micro-MKKS63 CRISPR-Cas9 knockout lines"]
Autophagy_Lysosomal_Dysfunction["Autophagy-Lysosomal Dysfunction"]
Oligodendrocyte_and_Myelin_Dysfunction["Oligodendrocyte and Myelin Dysfunction"]
Astrocyte_Plasma_Proteomic_Age_Gap["Astrocyte Plasma Proteomic Age Gap"]
Oligodendrocyte_Precursor_Cell_Plasma_Proteomic_Age_Gap["Oligodendrocyte Precursor Cell Plasma Proteomic Age Gap"]
Muscarinic_M1_Receptor_Signaling_Loss["Muscarinic M1 Receptor Signaling Loss"]
PSEN1["PSEN1"]
Digital_Alzheimers_Disease_Diagnosis_DADD_patient_specific_brain_model["Digital Alzheimer's Disease Diagnosis (DADD) patient-specific brain model"]
Microglial_Oxidative_Phosphorylation_Failure["Microglial Oxidative Phosphorylation Failure"]
Mitochondrial_Quality_Control_Failure["Mitochondrial Quality-Control Failure"]
Complement_Mediated_Microglial_Synapse_Elimination["Complement-Mediated Microglial Synapse Elimination"]
APOE["APOE"]
Micro_MKKS63_Microprotein_Depletion["Micro-MKKS63 Microprotein Depletion"]
Inhibitory_Neuron_Plasma_Proteomic_Age_Gap["Inhibitory Neuron Plasma Proteomic Age Gap"]
Adaptive_Immune_T_Cell_Response_to_Tau_Pathology["Adaptive Immune T Cell Response to Tau Pathology"]
Microglial_Lipid_Droplet_Accumulation["Microglial Lipid Droplet Accumulation"]
PSEN2["PSEN2"]
Synaptic_Dysfunction["Synaptic Dysfunction"]
Neurofibrillary_Tangle_Formation["Neurofibrillary Tangle Formation"]
Memory_Loss["Memory Loss"]
NLRP3["NLRP3"]
APP["APP"]
Vascular_Dysfunction["Vascular Dysfunction"]
Oral_glucosamine_supplementation["Oral glucosamine supplementation"]
HSV_1_Reactivation_in_RORB+_Glutamatergic_Neurons["HSV-1 Reactivation in RORB+ Glutamatergic Neurons"]
Amyloid_Plaque_Formation --> Neurofibrillary_Tangle_Formation
Amyloid_Plaque_Formation --> Synaptic_Dysfunction
Amyloid_Plaque_Formation --> Neuroinflammation
Neurofibrillary_Tangle_Formation --> Synaptic_Dysfunction
Neurofibrillary_Tangle_Formation --> Necroptotic_Neuronal_Death
Neurofibrillary_Tangle_Formation --> Intercellular_Tau_Transmission_via_Extracellular_Vesicles
Synaptic_Dysfunction --> Cortical_Structural_Connectivity_Degeneration
Synaptic_Dysfunction --> Memory_Loss
Cortical_Structural_Connectivity_Degeneration --> Memory_Loss
Neuroinflammation --> Amyloid_Plaque_Formation
Neuroinflammation --> Neurofibrillary_Tangle_Formation
Neuroinflammation --> Oxidative_Stress
Neuroinflammation --> Vascular_Dysfunction
Neuroinflammation --> Senescent_Cell_Accumulation
Oxidative_Stress --> Synaptic_Dysfunction
Mitochondrial_Quality_Control_Failure --> Amyloid_Plaque_Formation
Mitochondrial_Quality_Control_Failure --> Neurofibrillary_Tangle_Formation
Mitochondrial_Quality_Control_Failure --> Memory_Loss
Mitochondrial_Quality_Control_Failure --> Neuroinflammation
Vascular_Dysfunction --> Amyloid_Plaque_Formation
Vascular_Dysfunction --> Synaptic_Dysfunction
Glymphatic_Clearance_Failure --> Amyloid_Plaque_Formation
Autophagy_Lysosomal_Dysfunction --> Amyloid_Plaque_Formation
Autophagy_Lysosomal_Dysfunction --> Neurofibrillary_Tangle_Formation
HSV_1_Reactivation_in_RORB+_Glutamatergic_Neurons --> Synaptic_Dysfunction
Intercellular_Tau_Transmission_via_Extracellular_Vesicles --> Neurofibrillary_Tangle_Formation
PARP1_Mediated_Parthanatos --> Neuroinflammation
PARP1_Mediated_Parthanatos --> Oxidative_Stress
PARP1_Mediated_Parthanatos --> Mitochondrial_Quality_Control_Failure
Adaptive_Immune_T_Cell_Response_to_Tau_Pathology --> Synaptic_Dysfunction
Muscarinic_M1_Receptor_Signaling_Loss --> Amyloid_Plaque_Formation
Muscarinic_M1_Receptor_Signaling_Loss --> Neurofibrillary_Tangle_Formation
Complement_Mediated_Microglial_Synapse_Elimination --> Synaptic_Dysfunction
Neuronal_Endosomal_Lysosomal_Acidification_Failure --> Amyloid_Plaque_Formation
Neuronal_Endosomal_Lysosomal_Acidification_Failure --> Autophagy_Lysosomal_Dysfunction
Selective_Vulnerability_of_RORB+_Entorhinal_Excitatory_Neurons --> Neurofibrillary_Tangle_Formation
Necroptotic_Neuronal_Death --> Neuroinflammation
Senescent_Cell_Accumulation --> Neurofibrillary_Tangle_Formation
Senescent_Cell_Accumulation --> Neuroinflammation
Oligodendrocyte_and_Myelin_Dysfunction --> Amyloid_Plaque_Formation
Microglial_Lipid_Droplet_Accumulation --> Neurofibrillary_Tangle_Formation
Microglial_Lipid_Droplet_Accumulation --> Neuroinflammation
Interneuron_Dysfunction_and_Network_Hypersynchrony --> Memory_Loss
Tau_Induced_Nucleocytoplasmic_Transport_Failure --> Neurofibrillary_Tangle_Formation
Brain_N_Glycan_Hyperglycosylation --> Memory_Loss
Micro_MKKS63_Microprotein_Depletion --> Microglial_Oxidative_Phosphorylation_Failure
Cumulative_exposure_to_strong_central_anticholinergic_medication --> Muscarinic_M1_Receptor_Signaling_Loss
Oral_glucosamine_supplementation --> Brain_N_Glycan_Hyperglycosylation
Tau_Directed_Antisense_Oligonucleotide_Therapy --> Neurofibrillary_Tangle_Formation
HMC3_human_microglial_micro_MKKS63_CRISPR_Cas9_knockout_lines --> Microglial_Oxidative_Phosphorylation_Failure
Digital_Alzheimers_Disease_Diagnosis_DADD_patient_specific_brain_model --> Cortical_Structural_Connectivity_Degeneration
Digital_Alzheimers_Disease_Diagnosis_DADD_patient_specific_brain_model --> Synaptic_Dysfunction
Neuroinflammation -.-> Astrocyte_Plasma_Proteomic_Age_Gap
Neurofibrillary_Tangle_Formation -.-> Astrocyte_Plasma_Proteomic_Age_Gap
Neurofibrillary_Tangle_Formation -.-> Oligodendrocyte_Precursor_Cell_Plasma_Proteomic_Age_Gap
Synaptic_Dysfunction -.-> Inhibitory_Neuron_Plasma_Proteomic_Age_Gap
APP --> Amyloid_Plaque_Formation
APP --> Neuronal_Endosomal_Lysosomal_Acidification_Failure
APP --> Oligodendrocyte_and_Myelin_Dysfunction
PSEN1 --> Amyloid_Plaque_Formation
PSEN1 --> Neuronal_Endosomal_Lysosomal_Acidification_Failure
PSEN2 --> Amyloid_Plaque_Formation
APOE --> Microglial_Lipid_Droplet_Accumulation
APOE --> Oligodendrocyte_and_Myelin_Dysfunction
TREM2 --> Neuroinflammation
NLRP3 --> Neuroinflammation
PYCARD --> Neuroinflammation
LRP1 --> Vascular_Dysfunction
style Neuronal_Endosomal_Lysosomal_Acidification_Failure fill:#dbeafe
style Glymphatic_Clearance_Failure fill:#dbeafe
style Cumulative_exposure_to_strong_central_anticholinergic_medication fill:#dcfce7
style Necroptotic_Neuronal_Death fill:#dbeafe
style Senescent_Cell_Accumulation fill:#dbeafe
style PYCARD fill:#f3e8ff
style Brain_N_Glycan_Hyperglycosylation fill:#dbeafe
style TREM2 fill:#f3e8ff
style Cortical_Structural_Connectivity_Degeneration fill:#dbeafe
style Amyloid_Plaque_Formation fill:#dbeafe
style Oxidative_Stress fill:#dbeafe
style PARP1_Mediated_Parthanatos fill:#dbeafe
style Tau_Directed_Antisense_Oligonucleotide_Therapy fill:#fce7f3
style Tau_Induced_Nucleocytoplasmic_Transport_Failure fill:#dbeafe
style Selective_Vulnerability_of_RORB+_Entorhinal_Excitatory_Neurons fill:#dbeafe
style Intercellular_Tau_Transmission_via_Extracellular_Vesicles fill:#dbeafe
style Neuroinflammation fill:#dbeafe
style Interneuron_Dysfunction_and_Network_Hypersynchrony fill:#dbeafe
style LRP1 fill:#f3e8ff
style HMC3_human_microglial_micro_MKKS63_CRISPR_Cas9_knockout_lines fill:#ccfbf1
style Autophagy_Lysosomal_Dysfunction fill:#dbeafe
style Oligodendrocyte_and_Myelin_Dysfunction fill:#dbeafe
style Astrocyte_Plasma_Proteomic_Age_Gap fill:#e0e7ff
style Oligodendrocyte_Precursor_Cell_Plasma_Proteomic_Age_Gap fill:#e0e7ff
style Muscarinic_M1_Receptor_Signaling_Loss fill:#dbeafe
style PSEN1 fill:#f3e8ff
style Digital_Alzheimers_Disease_Diagnosis_DADD_patient_specific_brain_model fill:#ecfccb
style Microglial_Oxidative_Phosphorylation_Failure fill:#dbeafe
style Mitochondrial_Quality_Control_Failure fill:#dbeafe
style Complement_Mediated_Microglial_Synapse_Elimination fill:#dbeafe
style APOE fill:#f3e8ff
style Micro_MKKS63_Microprotein_Depletion fill:#dbeafe
style Inhibitory_Neuron_Plasma_Proteomic_Age_Gap fill:#e0e7ff
style Adaptive_Immune_T_Cell_Response_to_Tau_Pathology fill:#dbeafe
style Microglial_Lipid_Droplet_Accumulation fill:#dbeafe
style PSEN2 fill:#f3e8ff
style Synaptic_Dysfunction fill:#dbeafe
style Neurofibrillary_Tangle_Formation fill:#dbeafe
style Memory_Loss fill:#fef3c7
style NLRP3 fill:#f3e8ff
style APP fill:#f3e8ff
style Vascular_Dysfunction fill:#dbeafe
style Oral_glucosamine_supplementation fill:#dcfce7
style HSV_1_Reactivation_in_RORB+_Glutamatergic_Neurons fill:#dbeafe
name: com_Influenza__Alzheimer_Disease
creation_date: "2026-06-25T12:00:00Z"
curation_status: CANDIDATE
notes: >-
Tentative directional trajectory: severe influenza (notably influenza with
pneumonia) has been associated with later neurodegenerative disease, including
Alzheimer's disease and other dementias, in biobank and cohort studies. IMPORTANT
EVIDENCE CAVEAT: the Intercept essay cited "~4.5-5x dementia" and "~2.6-4.1x
Alzheimer's" risk after severe influenza/pneumonia. Those specific magnitudes
most plausibly trace to per-disease hazard ratios in the Levine 2023 (Neuron)
biobank study, but they appear in that paper's figures/tables and could NOT be
verified from the abstract; they are therefore NOT asserted here as quantitative
signals. Only the verifiable qualitative abstract statements are curated. The
adjacent Sipila 2021 cohort quantifies an infection->dementia association but is
for ANY hospital-treated infection, not influenza specifically. Kept as CANDIDATE
pending extraction of the influenza-specific HRs from full text.
disease_a:
slug: Influenza
disease_b:
slug: Alzheimer_Disease
directionality: A_BEFORE_B
literature_evidence:
- reference: PMID:36669485
reference_title: "Virus exposure and neurodegenerative disease risk across national biobanks."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Influenza with pneumonia was significantly associated with five of the six neurodegenerative diseases studied."
explanation: >-
Cross-biobank study reports that influenza with pneumonia is significantly
associated with multiple neurodegenerative diseases (the numeric per-disease
hazard ratios are in the source tables, not the abstract).
- reference: PMID:34166620
reference_title: "Hospital-treated infectious diseases and the risk of dementia: a large, multicohort, observational study with a replication cohort."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Hospitalisation for any infectious disease was associated with increased dementia risk in the primary cohort"
explanation: >-
Adjacent cohort evidence that hospital-treated infection is associated with
increased dementia risk; not influenza-specific, so only partial support for
the influenza->Alzheimer's trajectory.
hypotheses:
- description: >-
Severe influenza (especially with pneumonia) may contribute to later
neurodegeneration through systemic and neuroinflammation, cerebrovascular
injury, and accelerated amyloid/tau pathology; an alternative/competing
explanation is reverse causation or shared frailty/susceptibility, and the
influenza-specific effect size on Alzheimer's disease is not yet verified
here from primary full text.
evidence:
- reference: PMID:36669485
reference_title: "Virus exposure and neurodegenerative disease risk across national biobanks."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "we identified 45 viral exposures significantly associated with increased risk of neurodegenerative disease and replicated 22 of these associations."
explanation: >-
Supports a broader pattern of viral exposures associated with later
neurodegenerative disease, of which influenza-with-pneumonia is one.