YapSpan

What runs in families

Lifespan itself is barely heritable, but specific diseases do run in families.

Updated 2026-08-20

Test yourself: Family history quiz6 questions · ~1 minStart →

Family history, by the numbers

🌳
<10%

of how long you live is explained by your genes, per 400 million family-tree records. Spouses’ lifespans correlate almost as much as siblings’, so most “family resemblance” is habits, not DNA [1].

What a family history actually changes

Your risk with an affected close relative, versus without one

Parent with type 2 diabetes≈3x risk
Parent or sibling with early heart disease≈2x risk
Cancers caused by inherited single genes5–10% of all
Favorable lifestyle at worst genetic heart risk−46%
works in your favor works against you

[1] · [2] · [3] · National Cancer Institute

What you inherit from your family, and what you don’t

?%

What raises dementia risk most

50%25%0%25%50%75%100%← more risk · % change in risk · less risk →Factors, ranked by biggest effect1349%#1120%#2≈76%#312%60%#470%#570%#626%≈35%#760%#850%#949%#1044%#1140%#1240%#1330%#1430%#1530%#1626%#17≈4%20%#1823%#1923%#2023%#2122%#2220%#2320%#2420%#2519%#2610%#27Everythingelseno single number

Scroll sideways to see every factor →

Tap a pill to answer yours.

Where you sit

0 of 27 answered

Answer the 27 factors above to see which ones raise your own risk, which sit at the reference, and which the studies have no number for.

Relative risk versus each factor’s reference group; above the line is lower risk, below it higher.

Sources (28)Livingston G, Huntley J, Liu KY, et al., Lancet 2024 · Zhong et al., PLoS One 2015 · Yeo BSY, Song HJJMD, Toh EMS, et al., JAMA Neurol 2023 and 25 moreShow all
  1. [1]E. Genin et al. APOE and Alzheimer disease: a major gene with semi-dominant inheritance. Mol Psychiatry, 16(9):903-7, 2011. doi:10.1038/mp.2011.52 Evidence: Low
  2. [2]G. Livingston et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet, 404(10452):572-628, 2024. doi:10.1016/S0140-6736(24)01296-0 Evidence: Not graded (review)
  3. [3]S. A. Shumaker et al. Conjugated equine estrogens and incidence of probable dementia and mild cognitive impairment in postmenopausal women: Women's Health Initiative Memory Study. JAMA, 291(24):2947-58, 2004. doi:10.1001/jama.291.24.2947 Evidence: Moderate
  4. [4]S. A. Shumaker et al. Estrogen plus progestin and the incidence of dementia and mild cognitive impairment in postmenopausal women: the Women's Health Initiative Memory Study: a randomized controlled trial. JAMA, 289(20):2651-62, 2003. doi:10.1001/jama.289.20.2651 Evidence: Moderate
  5. [5]Y. Vinogradova et al. Use of menopausal hormone therapy and risk of dementia: nested case-control studies using QResearch and CPRD databases. BMJ, 374:n2182, 2021. doi:10.1136/bmj.n2182 Evidence: Low
  6. [6]N. Pourhadi et al. Menopausal hormone therapy and dementia: nationwide, nested case-control study. BMJ, 381:e072770, 2023. doi:10.1136/bmj-2022-072770 Evidence: Low
  7. [7]A. Sommerlad et al. Association of social contact with dementia and cognition: 28-year follow-up of the Whitehall II cohort study. PLoS Med, 16(8):e1002862, 2019. doi:10.1371/journal.pmed.1002862 Evidence: Low
  8. [8]D. A. R. Sutin et al. Sense of meaning and purpose in life and risk of incident dementia: New data and meta-analysis. Arch Gerontol Geriatr, 105:104847, 2023. doi:10.1016/j.archger.2022.104847 Evidence: High
  9. [9]C. A. C. Coupland et al. Anticholinergic Drug Exposure and the Risk of Dementia: A Nested Case-Control Study. JAMA Intern Med, 179(8):1084-1093, 2019. doi:10.1001/jamainternmed.2019.0677 Evidence: Low
  10. [10]K. H. Franks et al. Association of Stress with Risk of Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis. J Alzheimers Dis, 82(4):1573-1590, 2021. doi:10.3233/JAD-210094 Evidence: Low
  11. [11]L. Johansson et al. Midlife psychological stress and risk of dementia: a 35-year longitudinal population study. Brain, 133(Pt 8):2217-24, 2010. doi:10.1093/brain/awq116 Evidence: Low
  12. [12]B. S. Y. Yeo et al. Association of Hearing Aids and Cochlear Implants With Cognitive Decline and Dementia: A Systematic Review and Meta-analysis. JAMA Neurol, 80(2):134-141, 2023. doi:10.1001/jamaneurol.2022.4427 Evidence: High
  13. [13]M. Zuin et al. Risk of dementia in patients with atrial fibrillation: Short versus long follow-up. A systematic review and meta-analysis. Int J Geriatr Psychiatry, 36(10):1488-1500, 2021. doi:10.1002/gps.5582 Evidence: Moderate
  14. [14]G. Zhong et al. Smoking Is Associated with an Increased Risk of Dementia: A Meta-Analysis of Prospective Cohort Studies with Investigation of Potential Effect Modifiers. PLoS One, 10(3):e0118333, 2015. doi:10.1371/journal.pone.0118333 Evidence: High
  15. [15]Y. Leng et al. Association of Sleep-Disordered Breathing With Cognitive Function and Risk of Cognitive Impairment: A Systematic Review and Meta-analysis. JAMA Neurol, 74(10):1237-1245, 2017. doi:10.1001/jamaneurol.2017.2180 Evidence: Moderate
  16. [16]P. Iso-Markku et al. Physical activity as a protective factor for dementia and Alzheimer's disease: systematic review, meta-analysis and quality assessment of cohort and case-control studies. Br J Sports Med, 56(12):701-709, 2022. doi:10.1136/bjsports-2021-104981 Evidence: High
  17. [17]O. M. Shannon et al. Mediterranean diet adherence is associated with lower dementia risk, independent of genetic predisposition: findings from the UK Biobank prospective cohort study. BMC Med, 21(1):81, 2023. doi:10.1186/s12916-023-02772-3 Evidence: Low
  18. [18]S. Su et al. Leisure Activities and the Risk of Dementia. Neurology, 99(15), 2022. doi:10.1212/WNL.0000000000200929 Evidence: High
  19. [19]X. Qi et al. Dose-Response Meta-Analysis on Tooth Loss With the Risk of Cognitive Impairment and Dementia. J Am Med Dir Assoc, 22(10):2039-2045, 2021. doi:10.1016/j.jamda.2021.05.009 Evidence: Moderate
  20. [20]S. Asher et al. Periodontal health, cognitive decline, and dementia: A systematic review and meta-analysis of longitudinal studies. J Am Geriatr Soc, 70(9):2695-2709, 2022. doi:10.1111/jgs.17978 Evidence: Low
  21. [21]S. Sabia et al. Association of sleep duration in middle and old age with incidence of dementia. Nat Commun, 12(1):2289, 2021. doi:10.1038/s41467-021-22354-2 Evidence: Low
  22. [22]D. Hughes et al. Association of Blood Pressure Lowering With Incident Dementia or Cognitive Impairment: A Systematic Review and Meta-analysis. JAMA, 323(19):1934-1944, 2020. doi:10.1001/jama.2020.4249 Evidence: High
  23. [23]M. Eyting et al. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature, 641(8062):438-446, 2025. doi:10.1038/s41586-025-08800-x Evidence: Low
  24. [24]M. Pomirchy et al. Herpes Zoster Vaccination and Dementia Occurrence. JAMA, 333(23):2083-2092, 2025. doi:10.1001/jama.2025.5013 Evidence: Low
  25. [25]M. Taquet et al. The recombinant shingles vaccine is associated with lower risk of dementia. Nat Med, 30(10):2777-2781, 2024. doi:10.1038/s41591-024-03201-5 Evidence: Low
  26. [26]L. Shi et al. Sleep disturbances increase the risk of dementia: A systematic review and meta-analysis. Sleep Med Rev, 40:4-16, 2018. doi:10.1016/j.smrv.2017.06.010 Evidence: Moderate
  27. [27]O. M. Bubu et al. Sleep, Cognitive impairment, and Alzheimer's disease: A Systematic Review and Meta-Analysis. Sleep, 40(1), 2017. doi:10.1093/sleep/zsw032 Evidence: High
  28. [28]M. Melville et al. Menopause hormone therapy and risk of mild cognitive impairment or dementia: a systematic review and meta-analysis. Lancet Healthy Longev, 6(12):100803, 2025. doi:10.1016/j.lanhl.2025.100803 Evidence: Low
Open What Matters →

Learn more about all the dementia factors, with the factor-by-factor walkthrough on its own page.

The short version

  • •Lifespan itself is barely inherited. The largest study ever run — 400 million family-tree records — found the true heritability of longevity is likely under 10% once you account for people marrying people like themselves [1]. Your parents’ ages at death say very little about yours.
  • •Specific diseases are a different story: a parent with premature heart disease roughly doubles your risk [2], a parent with type 2 diabetes roughly triples it, and some cancers and early dementia cluster in families too.
  • •Genes are odds, not verdicts. In 55,000 people, those with the worst genetic heart-disease risk cut that risk nearly in half with a favorable lifestyle [3]. Nine in ten first heart attacks are explained by modifiable factors [4].
  • •Age of onset is the signal. A father with a heart attack at 50 means far more than a grandmother with one at 88 — late-life disease in a long-lived relative is close to noise.
  • •The real payoff of knowing your family history is earlier screening: it can move up your first colonoscopy, cholesterol checks, and glucose testing by years, which is where lives actually get saved.
Test yourself: Family history quiz6 questions · ~1 minStart →

Many people quietly believe their lifespan was decided the day a parent died young: “heart attacks run in my family, so that’s how I’ll go.” The research says something more interesting and more hopeful. How long your relatives lived barely predicts how long you will — but WHAT they got sick with, and how young, is real information you can act on. Here is what a family tree actually tells you, ranked by the strength of the evidence.

1

Longevity itself is barely heritable

Classic twin studies put the heritability of lifespan around 20–25% [5]. Then Calico and Ancestry analyzed 400 million pedigree records and found even that was inflated: spouses’ lifespans correlate almost as strongly as siblings’, because people marry people with similar backgrounds and habits. The true genetic share of longevity is likely below 10% [1].

Do this

Retire the “I’ll die when my dad died” math. More than 90% of what determines your lifespan is not that inheritance.

Take the family history quiz →
2

Early heart disease in a parent or sibling is real risk

In the Framingham Offspring cohort, having a parent with cardiovascular disease before 60 roughly doubled a person’s own risk, even after adjusting for their own blood pressure and cholesterol [2]. The younger the relative was, the stronger the signal.

Do this

If a parent or sibling had a heart attack, bypass, or stent before ~60, tell your doctor — it changes when statins and earlier testing are worth it. Then check your own numbers: the INTERHEART study found nine modifiable factors explain about 90% of first heart attacks [4].

Take the heart health quiz →
3

Genetic risk is not a verdict — lifestyle moves it a lot

Among 55,000 people ranked by genetic heart-disease risk, those in the WORST genetic quintile who lived favorably (no smoking, decent diet, regular activity, healthy weight) had nearly HALF the coronary events of those with the same genes who lived poorly [3]. The genes loaded the gun; behavior decided whether it fired.

Do this

If your family history scares you, treat it as a reason to be in the favorable-lifestyle group, not as a sentence. The worse your inherited odds, the more each healthy habit is worth.

Take the heart health quiz →
4

Type 2 diabetes runs strongly in families

One parent with type 2 diabetes roughly triples your risk; two parents raise it further ([6], InterAct cohort). But in the Diabetes Prevention Program trial, people already on the way to diabetes cut their progression by 58% with modest weight loss and 150 minutes of weekly activity — beating the drug metformin [7].

Do this

A diabetic parent or sibling means: ask for a fasting glucose or HbA1c test now, not at 45. Prediabetes caught early is one of the most reversible conditions in medicine.

Take the metabolic health quiz →
5

Cancer in the family usually isn’t a cancer syndrome

Only about 5–10% of cancers come from inherited single-gene mutations like BRCA or Lynch syndrome (National Cancer Institute). What matters is the pattern: the SAME cancer in multiple close relatives, unusually young ages at diagnosis, or rare cancers clustering together.

Do this

One relative with cancer at 75 is common and changes little. A first-degree relative with colorectal cancer, or breast cancer before 50, should move your screening up — the American Cancer Society recommends starting colonoscopy 10 years before the age your relative was diagnosed.

6

Dementia: family history matters less than the headlines say

Late-life Alzheimer’s in a parent nudges your risk; it does not determine it. The 2024 Lancet Commission attributes about 45% of dementia risk to 14 modifiable factors — hearing loss, blood pressure, exercise, smoking, social contact among them. The FINGER trial showed a lifestyle package measurably improved cognition in at-risk older adults [8].

Do this

If dementia is in your family, the highest-evidence moves are boring and powerful: control blood pressure in midlife, stay active, treat hearing loss, stay socially connected.

7

Exceptional longevity DOES cluster — in the extreme tail

The one place genes clearly show up is the far end: longevity defined as being in the top 10% of survivors of your generation is transmitted in families, and the effect compounds with each long-lived relative [9]. Parents and grandparents past 90 meaningfully raise your own odds of getting there.

Do this

If your tree is full of 90-somethings, that’s a genuine tailwind — worth knowing, not worth coasting on. If it isn’t, remember item 1: the absence of long-lived ancestors barely predicts anything.

Take the family history quiz →
8

Some of what “runs in the family” is the household, not the genes

Families share cooking, smoking habits, activity norms, stress patterns, and zip codes — all of which travel down generations without a single gene involved. This shared environment is precisely why simple family-history numbers overstate genetics [1], and it’s also good news: unlike your genome, you can move out of an inherited lifestyle.

Do this

When you note a condition in a relative, ask what else you inherited with it — the diet, the smoking, the sedentary evenings. Those are yours to change.

How to tell if yours is good

Signals you can read yourself, starting today, and what a good reading looks like.

A parent or sibling with heart disease, stroke, or diabetes before ~60

None you know of — or you know of one and your own numbers are checked and managed

Same cancer in 2+ close relatives, or any diagnosed before ~50

No such pattern — or you’ve told a doctor and your screening schedule reflects it

You know your close relatives’ major conditions and rough ages of onset

You could fill in a family tree from memory — knowing is the whole game

How you think about a relative who died young

As one data point that changed your screening, not a prophecy about your own lifespan

Check your own risk

5 quick questions about you, not the article. You get a personal readout of where your risks sit.

Pick an answer to reveal the numbers: check points for every answer (+2p working for you, +1p worth tightening, +0p elevated risk), plus life-model years where an answer maps to one (+0y = measured, no effect on its own).

1. Did a parent or sibling develop heart disease, stroke, or type 2 diabetes before about 60?

2. Any strong family history of cancer in your close family?

3. Any strong family history of dementia in your close family?

4. Could you fill in your close relatives’ major conditions and rough ages of onset from memory?

5. Do you still carry the habits of the household you grew up in — the cooking, smoking, or sedentary evenings?

Now score your own

These two-minute quizzes turn this research into your numbers, and the years they are worth.

Family history quizHeart health quizMetabolic health quizPreventive care quiz

Go deeper in the Wiki

Family history and genetics →

Sources

  1. [1]J. G. Ruby et al. Estimates of the Heritability of Human Longevity Are Substantially Inflated due to Assortative Mating. Genetics, 210(3):1109-1124, 2018. doi:10.1534/genetics.118.301613 Evidence: Low
  2. [2]D. M. Lloyd-Jones et al. Parental cardiovascular disease as a risk factor for cardiovascular disease in middle-aged adults: a prospective study of parents and offspring. JAMA, 291(18):2204-11, 2004. doi:10.1001/jama.291.18.2204 Evidence: Low
  3. [3]A. V. Khera et al. Genetic Risk, Adherence to a Healthy Lifestyle, and Coronary Disease. N Engl J Med, 375(24):2349-2358, 2016. doi:10.1056/NEJMoa1605086 Evidence: Moderate
  4. [4]S. Yusuf et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet, 364(9438):937-52, 2004. doi:10.1016/S0140-6736(04)17018-9 Evidence: Moderate
  5. [5]A. M. Herskind et al. The heritability of human longevity: a population-based study of 2872 Danish twin pairs born 1870-1900. Hum Genet, 97(3):319-23, 1996. doi:10.1007/BF02185763 Evidence: Low
  6. [6]InterAct Consortium et al. The link between family history and risk of type 2 diabetes is not explained by anthropometric, lifestyle or genetic risk factors: the EPIC-InterAct study. Diabetologia, 56(1):60-9, 2013. doi:10.1007/s00125-012-2715-x Evidence: Moderate
  7. [7]W. C. Knowler et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med, 346(6):393-403, 2002. doi:10.1056/NEJMoa012512 Evidence: Moderate
  8. [8]T. Ngandu et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet, 385(9984):2255-63, 2015. doi:10.1016/S0140-6736(15)60461-5 Evidence: Moderate
  9. [9]N. van den Berg et al. Longevity defined as top 10% survivors and beyond is transmitted as a quantitative genetic trait. Nat Commun, 10(1):35, 2019. doi:10.1038/s41467-018-07925-0 Evidence: Moderate
  10. [10]G. Livingston et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. Lancet, 404(10452):572-628, 2024. doi:10.1016/S0140-6736(24)01296-0 Evidence: Not graded (review)
  11. [11]National Cancer Institute. The Genetics of Cancer. National Cancer Institute. Evidence: Not graded (reference page)
  12. [12]American Cancer Society. American Cancer Society Guideline for Colorectal Cancer Screening. American Cancer Society. Evidence: Not graded (guideline)
  13. [13]A. Dutta et al. Longer lived parents: protective associations with cancer incidence and overall mortality. J Gerontol A Biol Sci Med Sci, 68(11):1409-18, 2013. doi:10.1093/gerona/glt061 Evidence: Low
  14. [14]L. A. Mucci et al. Familial Risk and Heritability of Cancer Among Twins in Nordic Countries. JAMA, 315(1):68-76, 2016. doi:10.1001/jama.2015.17703 Evidence: Moderate
  15. [15]F. J. Wolters et al. Parental family history of dementia in relation to subclinical brain disease and dementia risk. Neurology, 88(17):1642-1649, 2017. doi:10.1212/WNL.0000000000003871 Evidence: Low
  16. [16]S. Seshadri et al. Parental occurrence of stroke and risk of stroke in their children: the Framingham study. Circulation, 121(11):1304-12, 2010. doi:10.1161/CIRCULATIONAHA.109.854240 Evidence: Low
  17. [17]Murphy SL, Kochanek KD, Xu J, Arias E. Mortality in the United States, 2023 (NCHS Data Brief No. 521). National Center for Health Statistics, 2024. Evidence: Not graded (statistics)

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YapSpan estimates are for reflection and entertainment only. They are not medical advice, a diagnosis, or a prediction of any individual outcome. Check with a doctor before making any medical decision.