EPISODE · Nov 3, 2025 · 1H 11M
Shingles Shot and Dementia: Could one vaccine protect your brain?
from Normal Curves: Sexy Science, Serious Statistics · host Regina Nuzzo and Kristin Sainani
What do chickenpox and shingles have to do with your brain? This week, we dig into two 2025 headline-grabbing studies that link the shingles shot to lower dementia rates. We start in Wales, where a birthday cutoff turned into the perfect natural experiment, and end in the U.S. with a multi-million-person megastudy. Featuring bias-variance Goldilockses, Fozzy-the-Bear regression discontinuities, a Barbie-versus-Oppenheimer showdown for propensity scores – and the hottest rebrand of inverse-probability weighting you’ll ever hear.Statistical topicsAbsolute vs. relative riskBias–variance tradeoffCausal inferenceCensoringConfoundingFuzzy regression discontinuity designHealthy-user biasInverse probability of treatment weighting (IPTW)Longitudinal studyNatural experimentNegative controlsOptimal bandwidthPropensity scoresSelection biasSubgroup analysisTriangular kernel weightsMethodological morals“Propensity scores are the lipstick you put on observational pigs.”“Natural experiments are a hot flirtation date with causality.”ReferencesEyting M, Xie M, Michalik F, Heß S, Chung S, Geldsetzer P. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025 May;641(8062):438-446. doi: 10.1038/s41586-025-08800-x. Epub 2025 Apr 2. PMID: 40175543; PMCID: PMC12058522.Polisky V, Littmann M, Triastcyn A, et al. Varicella-zoster virus reactivation and the risk of dementia. Nat Med. Published online October 6, 2025. doi:10.1038/s41591-025-03972-5Sainani KL. Propensity scores: uses and limitations. PM&R 2012; 4:693-97.Detailed Show Notes PageKristin and Regina’s online courses: Demystifying Data: A Modern Approach to Statistical Understanding Clinical Trials: Design, Strategy, and Analysis Medical Statistics Certificate Program Writing in the Sciences Epidemiology and Clinical Research Graduate Certificate Program Programs that we teach in:Epidemiology and Clinical Research Graduate Certificate Program Find us on:Kristin - LinkedIn & Twitter/XRegina - LinkedIn & ReginaNuzzo.com(00:00) - Intro and first gratuitous mention of sex (03:56) - What are shingles, chickenpox, and the vaccines against them? (12:30) - Fun facts about the varicella zoster and herpes viruses (17:16) - A natural experiment in Wales (21:10) - What is the Goldilocks optimal bandwidth? (25:33) - Fuzzy regression discontinuity design demystified (31:59) - Shingles vaccine vs dementia showdown (33:29) - Absolute risk reduction paradox (37:00) - Effects for men and women differ (39:48) - A giant longitudinal study (46:32) - Propensity scores demystified via Barbie and Oppenheimer (52:36) - Using propensity scores to make matches (56:49) - Inverse probability of treatment weighting demystified via more Barbenheimer (01:01:08) - Attempts to rename IPTW for TikTok (01:04:40) - Longitudinal study results (01:08:41) - Smooch ratings and methodological morals: pigs and hot dates
What this episode covers
What do chickenpox and shingles have to do with your brain? This week, we dig into two 2025 headline-grabbing studies that link the shingles shot to lower dementia rates. We start in Wales, where a birthday cutoff turned into the perfect natural experiment, and end in the U.S. with a multi-million-person megastudy. Featuring bias-variance Goldilockses, Fozzy-the-Bear regression discontinuities, a Barbie-versus-Oppenheimer showdown for propensity scores – and the hottest rebrand of inverse-probability weighting you’ll ever hear.Statistical topicsAbsolute vs. relative riskBias–variance tradeoffCausal inferenceCensoringConfoundingFuzzy regression discontinuity designHealthy-user biasInverse probability of treatment weighting (IPTW)Longitudinal studyNatural experimentNegative controlsOptimal bandwidthPropensity scoresSelection biasSubgroup analysisTriangular kernel weightsMethodological morals“Propensity scores are the lipstick you put on observational pigs.”“Natural experiments are a hot flirtation date with causality.”ReferencesEyting M, Xie M, Michalik F, Heß S, Chung S, Geldsetzer P. A natural experiment on the effect of herpes zoster vaccination on dementia. Nature. 2025 May;641(8062):438-446. doi: 10.1038/s41586-025-08800-x. Epub 2025 Apr 2. PMID: 40175543; PMCID: PMC12058522.Polisky V, Littmann M, Triastcyn A, et al. Varicella-zoster virus reactivation and the risk of dementia. Nat Med. Published online October 6, 2025. doi:10.1038/s41591-025-03972-5Sainani KL. Propensity scores: uses and limitations. PM&R 2012; 4:693-97.Detailed Show Notes PageKristin and Regina’s online courses: Demystifying Data: A Modern Approach to Statistical Understanding Clinical Trials: Design, Strategy, and Analysis Medical Statistics Certificate Program Writing in the Sciences Epidemiology and Clinical Research Graduate Certificate Program Programs that we teach in:Epidemiology and Clinical Research Graduate Certificate Program Find us on:Kristin - LinkedIn & Twitter/XRegina - LinkedIn & ReginaNuzzo.com(00:00) - Intro and first gratuitous mention of sex (03:56) - What are shingles, chickenpox, and the vaccines against them? (12:30) - Fun facts about the varicella zoster and herpes viruses (17:16) - A natural experiment in Wales (21:10) - What is the Goldilocks optimal bandwidth? (25:33) - Fuzzy regression discontinuity design demystified (31:59) - Shingles vaccine vs dementia showdown (33:29) - Absolute risk reduction paradox (37:00) - Effects for men and women differ (39:48) - A giant longitudinal study (46:32) - Propensity scores demystified via Barbie and Oppenheimer (52:36) - Using propensity scores to make matches (56:49) - Inverse probability of treatment weighting demystified via more Barbenheimer (01:01:08) - Attempts to rename IPTW for TikTok (01:04:40) - Longitudinal study results (01:08:41) - Smooch ratings and methodological morals: pigs and hot dates
NOW PLAYING
Shingles Shot and Dementia: Could one vaccine protect your brain?
No transcript for this episode yet
Similar Episodes
Jun 15, 2022 ·8m
May 25, 2022 ·20m
May 19, 2022 ·16m
May 15, 2022 ·34m
May 12, 2022 ·1m