- 475studies in the library match, of 29,780
- 29name it in the title
- 1964–2026years published
- 459peer-reviewed articles
The query: title or abstract mentions "smoking", "smoker", "cigarette", "tobacco" or "nicotine", matched case-insensitively against each record's title and abstract (its summary field) in alzhub's library of 29,780 study records, as of 2026-11-09. Every count on this page comes from that match. The matched list as JSON.
Smoking damages blood vessels throughout the body including the brain, promotes inflammation and oxidative stress, and is tied to stroke and heart disease, all of which feed into dementia risk. Older studies sometimes suggested nicotine might protect against Alzheimer's; later work attributed that to smokers dying younger, before the age at which dementia is common. The research now asks how much risk falls after quitting, and how quickly.
This page describes what published research in alzhub's library reports. It is not medical advice and does not apply to any one person: a doctor who knows the person's history is the only one who can say what a result or a treatment means for them.
What the studies report, in their own words
Whole sentences copied from the abstract or key findings of the highest-scoring matched studies, chosen because they mention the subject and give a figure. 8 of the 475 matched records are quoted; each links to its study page and from there to the paper.
“Approximately 30%-40% of dementia cases have been estimated to be attributed to modifiable risk factors, including hypertension, smoking and sedentary lifestyle.”
“Overall, 28·8 million (95% UI 24·5-34·0) DALYs were attributed to dementia; 6·4 million (95% UI 3·4-10·5) of these could be attributed to the modifiable GBD risk factors of high BMI, high fasting plasma glucose, smoking, and a high intake of sugar-sweetened beverages.”
“Importance Previous estimates suggested that 1 in 3 cases of Alzheimer disease and related dementia (ADRDs) in the US are associated with modifiable risk factors, the most prominent being physical inactivity, depression, and smoking.”
“Meta-analysis of 31 studies with incident AD yielded pooled RR for low education (RR = 1.99; 95% CI: 1.30-3.04), high Hcy (RR = 1.93; 95% CI: 1.50-2.49), and current/ever smoking status (RR = 1.37; 95% CI: 1.23-1.52) while indicating protective effects of higher physical activity and n-3 fatty acids.”
“Results We included 207 studies and found high or moderate certainty that the following 49 variables provide valuable prognostic information on mortality and/or severe disease in patients with COVID-19 infectious disease: Demographic factors (age, male sex, smoking), patient history factors (comorbi”
“In Cox proportional hazards models adjusted for education, smoking status, presence of at least one APOE epsilon4 allele, and history of stroke or diabetes at baseline, persons who had used statins were about half as likely as those who did not use statins to develop dementia/CIND (HR = 0.52; 95% CI 0.34, 0.80).”
“Results We report significant associations between age acceleration and body mass index, total cholesterol to high-density lipoprotein cholesterol ratios, socioeconomic status, high blood pressure, and smoking behavior (Bonferroni-adjusted P < .05).”
“Among current smokers, this relationship was most pronounced (RRs, 0.65 [95% CI, 0.37-1.14] and 0.58 [95% CI, 0.30-1.12], respectively) and also was present for intake of beta carotene (RR, 0.49 [95% CI, 0.27-0.92]) and flavonoids (RR, 0.54 [95% CI, 0.31-0.96]).”
What kind of evidence it is
By study design
| Design (as recorded) | Studies |
|---|---|
| Systematic review or meta-analysis | 37 |
| Randomised controlled trial | 7 |
| Other clinical trial | 3 |
| Cohort or longitudinal study | 89 |
| Case-control study | 17 |
| Cross-sectional study | 35 |
| Other recorded design | 4 |
| No design recorded | 283 |
The design is the one named in alzhub's record for the study; a record with none is counted as "no design recorded".
By year
| Year | Studies | Share |
|---|---|---|
| 2026 | 24 | |
| 2025 | 88 | |
| 2024 | 14 | |
| 2023 | 19 | |
| 2022 | 20 | |
| 2021 | 34 | |
| 2020 | 18 | |
| 2019 | 21 | |
| 2018 | 15 | |
| 2017 | 17 | |
| 2016 and earlier | 205 |
Other counts within the matched set
| Peer-reviewed articles | 459 |
| Marked open access in the record | 184 |
| Rated "high" evidence strength in alzhub's summary | 70 |
| Rated "moderate" evidence strength in alzhub's summary | 158 |
| Rated "low" evidence strength in alzhub's summary | 244 |
| No evidence-strength rating | 3 |
| Records stating a participant count | 213 |
| Median participants (those records) | 1,686 |
| Largest participant count | 3,142,673 |
Within the 475 matched studies
| Studies… | Count | Rule |
|---|---|---|
| …that mention quitting or former smokers | 32 | the abstract also contains "quit", "cessation", "former smoker" or "ex-smoker" |
| …about midlife smoking | 73 | the abstract also contains "midlife" or "middle age" |
| …that report a hazard ratio | 63 | the abstract also contains "hazard ratio" or "HR" |
The 10 highest-scoring matched studies
Title matches first, then by alzhub's usefulness score, which rates a study's design, journal, evidence and recency, not whether its result is good news.
- Smoking as a risk factor for dementia and cognitive decline: a meta-analysis of prospective studies
- Smoking and risk of dementia and Alzheimer's disease in a population-based cohort study: the Rotterdam Study
- Relation between smoking and risk of dementia and Alzheimer disease: the Rotterdam Study
- Smoking and increased Alzheimer's disease risk: a review of potential mechanisms
- Cigarette Smoking is a Risk Factor for Alzheimer's Disease: An Analysis Controlling for Tobacco Industry Affiliation
- Smoking is associated with an increased risk of dementia: a meta-analysis of prospective cohort studies with investigation of potential effect modifiers
- Smoking Cessation, Weight Change, and Risk of Dementia: A Prospective Cohort Study
- Effect of smoking on global cognitive function in nondemented elderly
- Relationship of Cigarette Smoking and Time of Quitting with Incident Dementia and Cognitive Decline
- The effect of alcohol and tobacco consumption, and apolipoprotein E genotype, on the age of onset in Alzheimer's disease
Systematic reviews and meta-analyses in the set
37 of the matched records are recorded as a systematic review, meta-analysis or umbrella review; the highest-scoring not already listed above:
- Risk factors for mortality in elderly patients with hip fractures: a meta-analysis of 18 studies
- Association of the Mediterranean Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) Diet With the Risk of Dementia
- Global, regional, and national burden of Alzheimer's disease and other dementias, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016
- Risk Factors Associated With Alzheimer Disease and Related Dementias by Sex and Race and Ethnicity in the US
- Western diet is associated with a smaller hippocampus: a longitudinal investigation
Newest matched studies
- Retinal biomarkers and dementia risk: A review of evidence across the 14 Lancet modifiable risk factors for dementia
- Carbonaceous Components Underlying Wildfire Smoke PM 2.5 -Associated Alzheimer’s Disease and Related Dementias in Older US Adults
- The microbial soy metabolite S-equol mitigates cadmium neurotoxicity in mice
- Varenicline as a Repurposable Drug Candidate for ADRD Prevention
- Regional choroid plexus calcifications and their associations with aging, brain structure, and disease
Journals with the most matched studies
| Journal | Studies |
|---|---|
| Neurology | 33 |
| Journal of Alzheimer's disease : JAD | 20 |
| Alzheimer's & dementia : the journal of the Alzheimer's Association | 12 |
| Stroke | 11 |
| Alzheimer s & Dementia | 10 |
Questions
- Does quitting smoking lower dementia risk?
- Cohort studies that follow people after they quit generally find risk falling towards that of never-smokers over years. The quoted papers give the figures and the follow-up times behind them.
- How many studies on smoking and dementia does alzhub hold?
- 475 of the 29,780 study records in alzhub's library match the query "title or abstract mentions "smoking", "smoker", "cigarette", "tobacco" or "nicotine""; 29 of them name it in the title. Counted from the records when this page was built.
- What kinds of study are they?
- 37 systematic review or meta-analysis, 7 randomised controlled trials, 3 other clinical trials, 89 cohort or longitudinal studys, 17 case-control studys, 35 cross-sectional studys; 283 record no design.
- What is the most recent study in the set?
- "Retinal biomarkers and dementia risk: A review of evidence across the 14 Lancet modifiable risk factors for dementia" (PsyArXiv, 2026), the newest by publication date among the matched records.
- Which journals publish most on it?
- Neurology (33); Journal of Alzheimer's disease : JAD (20); Alzheimer's & dementia : the journal of the Alzheimer's Association (12), counted across the matched records.
Read on
- PreventionWhat has been properly tested.
- Alcohol and dementiaThe other common exposure in the same cohorts.
- Risk factors, rankedSmoking among the modifiable risks.