Pillar 03 · Brain
Brain health starts decades before memory changes
Dementia can feel like fate, but a large share of the risk is modifiable. The 2024 Lancet standing Commission estimates that around 45% of dementia cases are associated with 14 modifiable risk factors acting across a lifetime [Livingston G, 2024], up from 12 factors and roughly 40% in its 2020 report [Livingston G, 2020]. That is a population estimate, not an individual guarantee, but the direction is clear: what happens across midlife matters, and it matters early.
The most useful starting point is that much of what protects the heart and metabolism also protects the brain. Several of the Commission’s risk factors are the same vascular and metabolic levers covered on the Heart and Metabolism pages: hypertension, diabetes, and (new in the 2024 update) high LDL cholesterol. So the calculators there apply here too.
Blood pressure
Hypertension is a modifiable dementia risk factor, and the Commission’s proactive, prevention-oriented recommendation is to keep systolic blood pressure at or below 130 mmHg from age 40 [Livingston G, 2024]. That target is earlier and lower than waiting for a diagnosis. The excess risk is concentrated in untreated high blood pressure and largely attenuates once it is treated.
Category: Normal
Zones follow the 2017 ACC/AHA categories; because the higher of the systolic and diastolic categories applies, the bands are L-shaped. Your reading is the dot. The dashed green box is the prevention-optimal target: the 2025 ACC/AHA guidance to get as close to under 120/80 as tolerated. Judge yourself against home readings (rested, seated, averaged); office readings run high.
Sources
Blood sugar (A1C)
Diabetes is on the Commission’s list of modifiable dementia risk factors [Livingston G, 2024]. A1C is the standard marker for average blood glucose, and the metabolic dysfunction it reflects tracks with brain risk as well as cardiovascular risk.
Category: Normal
Estimated average glucose: 108 mg/dL
ADA cut-points: normal <5.7%, prediabetes 5.7–6.4%, diabetes ≥6.5%. eAG via the ADAG regression (28.7 × A1C − 46.7).
Sources
ApoB / LDL cholesterol
The 2024 update newly added high LDL cholesterol as a dementia risk factor, tied with hearing loss as the largest single contributor by population share [Livingston G, 2024]. LDL cholesterol is the measure the Commission used; ApoB counts the same atherogenic particles more completely (see the Heart page for why particle count beats concentration).
Tier: High
Sources
- Sniderman AD, et al. Apolipoprotein B Particles and Cardiovascular Disease: A Narrative Review (2019)
- Ference BA, et al. Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the EAS Consensus Panel (2017)
- Giugliano RP, et al. Clinical efficacy and safety of achieving very low LDL-cholesterol concentrations with the PCSK9 inhibitor evolocumab: a prespecified secondary analysis of the FOURIER trial (2017)
- Blumenthal RS, et al. 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia (2026)
Still to come
This page is a starting skeleton. The brain-specific levers still to be written up, each sourced and where useful given its own calculator, include:
- Hearing loss: one of the largest single modifiable factors (~7% of cases) [Livingston G, 2024]. Treating it is promising but not yet proven in randomized trials, so the case is currently strongest for people who already carry other risk factors.
- Air pollution, smoking, and excess alcohol.
- Sleep, physical activity, and social and cognitive engagement.
- Vision loss (untreated), also new to the 2024 list.
- APOE genotype: a common genetic risk factor, and how to think about a risk you cannot change.