Five Lancet factors cluster around vascular and metabolic health. They share underlying biology, often co-occur, and respond to overlapping interventions. Together, they account for a substantial portion of preventable dementia — and notably, they are the factors that primary care medicine already addresses as cardiovascular risk. The longevity-psychiatry insight is that cardiovascular risk factor management is also cognitive risk factor management, and the brain endpoint should be explicit in the clinical conversation.
Hypertension accounts for approximately 2% preventable fraction in the Lancet framework, though this likely underestimates the true effect because of how the studies have been done. Sustained elevated blood pressure damages small vessels in the brain, contributes to vascular cognitive impairment, and accelerates the accumulation of white matter disease that compounds with neurodegenerative pathology. The SPRINT-MIND trial demonstrated that intensive blood pressure control (systolic under 120, though current consensus is under 130) reduced incidence of mild cognitive impairment. The clinical implication is that the cognitive-protection target is under 130 systolic, not the older general-population target of 140.
Diabetes accounts for approximately 2% preventable fraction. The metabolic-cognitive link runs through insulin resistance, chronic glycemic variability, cerebrovascular disease, and the increasingly characterized pathway some researchers call “Type 3 diabetes” — Alzheimer’s pathology with substantial insulin signaling dysregulation. Glycemic control matters; the goal is durable normalization, not just A1c targeting. Patients with diabetes have approximately a 60% increased risk of dementia compared to non-diabetic peers. Pre-diabetes is also relevant — the metabolic trajectory matters before diagnostic thresholds are crossed.
Obesity in midlife (not late-life — the relationship inverts after age 65) accounts for approximately 1% preventable fraction. The mechanism is partly direct — adipose-derived inflammation, insulin resistance — and partly indirect, through overlap with diabetes, hypertension, sleep apnea, and physical inactivity. Midlife BMI in the obese range is associated with elevated dementia risk in long-term follow-up. The clinical conversation is delicate because weight is a complex, multidimensional issue — but the longevity-psychiatry framing makes the brain endpoint visible to patients in a way that pure cardiovascular framing does not always achieve.
Physical inactivity accounts for approximately 2% preventable fraction. Aerobic activity that maintains VO2max in higher quartiles is among the most consistently evidence-supported interventions across cognitive aging research. The mechanism includes BDNF elevation, neurogenesis support, cerebrovascular health, glucose regulation, mood improvement, and sleep enhancement. The dose-response curve appears roughly linear above a minimum threshold — more is better, within reason. The clinical task is to make exercise a real prescription, with specific dose recommendations, not a generic “you should exercise.”
LDL cholesterol was added in the 2024 Lancet update, with an estimated preventable fraction of approximately 7% — making it one of the highest single factors. The evidence basis is the accumulating data linking midlife hypercholesterolemia with later dementia risk, mediated through cardiovascular and neuroinflammatory mechanisms. The relevant target is midlife apoB-containing lipoproteins; the relevant intervention is the same lipid-lowering therapy that cardiology already deploys for cardiovascular protection. The longevity-psychiatry implication is that apoB should be measured and treated to cognitive-protection targets, which are similar to or more aggressive than standard cardiology targets.
The cluster shares biology — insulin resistance, inflammation, cerebrovascular disease, oxidative stress — and the interventions overlap. A patient who is treating hypertension, controlling glycemia, maintaining physical activity, controlling apoB, and avoiding midlife obesity is addressing a single interconnected substrate, not five separate problems. The clinical efficiency comes from this overlap: the work that protects the heart also protects the brain, and framing it explicitly as brain protection often produces better adherence than cardiovascular framing alone.