Normal Curves: Sexy Science, Serious Statistics – Détails, épisodes et analyse

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/X
Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Introduction
(02:27) - Pheromone Dating Parties
(06:57) - Pheromone Dating Sites and Genetic Matching
(10:47) - The Science of HLA Genes and Mate Selection
(18:08) - Breaking Down the Original Sweaty T-Shirt Study
(23:08) - Study Design Flaws and Data Transparency Issues
(27:31) - Statistical Flaws: Correlated Observations Explained
(35:22) - Analyzing the Study's Questionable Results
(38:18) - The Pill's Influence on Scent Preferences
(41:26) - Overstated Conclusions and Wandering Discussions
(46:09) - Media Reactions and the Study’s Public Impact
(52:22) - Other Studies and their results
(55:01) - Conclusion

Normal Curves: Who are we and what is this podcast about?

Épisode 1

lundi 17 février 2025 • Durée 13:31

Welcome to a lively conversation about science that's like a journal club, but with less jargon, more fun, and a touch of PG-13 flair. In this introduction, Professors Regina Nuzzo and Kristin Sainani share how they met in graduate school, what they’ve been doing since then, how they’ll choose edgy topics and journal articles to dissect, and a bit about what makes them tick. Join them for their fresh, engaging take on scientific studies, data analysis, and statistical sleuthing.

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding

Epidemiology and Clinical Research Graduate Certificate Program

Program that we teach in:

Find us on:
Kristin - LinkedIn & Twitter/X
Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Introduction to Normal Curves
(03:49) - How We Met and Our Lasting Friendship
(05:24) - Career Paths
(08:07) - The Art of Evaluating Scientific Studies
(09:06) - Personal Health Journeys and Biases
(10:48) - Shameless Course Plugs & Teaching
(12:37) - Podcast Origins & Conclusion

Normal Curves Trailer

jeudi 13 février 2025 • Durée 02:09

Vitamin D Part 2: Good for more than just your bones?

Épisode 4

lundi 24 mars 2025 • Durée 01:09:19

Can you really sit on your couch, pop vitamin D pills, and shave seconds off your 5k? Touted as a miracle cure-all, vitamin D is claimed to slash cancer and infection risks while boosting mood, cognition, and athletic performance. But does upping your vitamin D really make you healthier and happier? In this episode, we’ll follow the epidemiologic evidence—from clues in petri dishes through randomized trials. Along our journey, we’ll encounter chocolate-fueled Nobel Prizes, rock stars, pasty Brits, and a tangled mess of promiscuous variables.

Statistical topics

ecological studies
ecological fallacy
correlation is not causation
observational studies
statistical adjustment
confounding
randomized trials
factorial design
post-hoc analyses
subgroup analyses

Methodologic morals

“Variables with too many entanglements make observational studies a fool’s game.”
“If your intervention works only when you torture your data, it’s probably a false confession.”

Citations

Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer? Int J Epidemiol. 1980;9:227-31.

Messerli FH. Chocolate consumption, cognitive function, and Nobel laureates. N Engl J Med. 2012;367:1562-64.

Holick, MF. The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problems. Penguin Publishing Group, 2011.

McMillan A. Can vitamin D boost your fitness routine? Dec 18, 2018.

Marawan A, Kurbanova N, Qayyum R. Association between serum vitamin D levels and cardiorespiratory fitness in the adult population of the USA. Eur J Prev Cardiol. 2019;26:750-55.

Vitamin D levels in the blood linked to cardiorespiratory fitness. European Society of Cardiology. Oct 30, 2018.

Jones AM, Kirby BS, Clark IE, et al. Physiological demands of running at 2-hour marathon race pace. J Appl Physiol. 2021;130:369-79.

Manson JE, Bassuk SS, Lee IM, et al. The VITamin D and OmegA-3 TriaL (VITAL): rationale and design of a large randomized controlled trial of vitamin D and marine omega-3 fatty acid supplements for the primary prevention of cancer and cardiovascular disease. Contemp Clin Trials. 2012;33:159-71.

Manson JE, Cook NR, Lee IM, et al. Vitamin D supplements and prevention of cancer and cardiovascular disease. NEJM. 2019;380:33-44.

Lee KL, McNeer JF, Starmer CF, et al. Clinical judgment and statistics: lessons from a simulated randomized trial in coronary artery disease. Circulation. 1980; 61:508-15.

Wood S. VITAL: No Benefits to Vitamin D and Omega-3s in Reducing Major CV Events, Cancer. TCTMD.com. Nov 10, 2018.

Neale RE, Baxter C, Romero BD, et al. The D-Health Trial: a randomised controlled trial of the effect of vitamin D on mortality. Lancet Diabetes Endocrinol. 2022;10:120-28.

Okereke OI, Reynolds CF, Mischoulon D, et al. Effect of Long-term Vitamin D3 Supplementation vs Placebo on Risk of Depression or Clinically Relevant Depressive Symptoms and on Change in Mood Scores: A Randomized Clinical Trial. JAMA. 2020;324:471-80.

LeBoff MS, Murata EM, Cook NR, et al. VITamin D and OmegA-3 TriaL (VITAL): Effects of Vitamin D Supplements on Risk of Falls in the US Population. J Clin Endocrinol Metab. 2020;105:2929-38.

Albert CM, Cook NR, Pester J, et al. Effect of Marine Omega-3 Fatty Acid and Vitamin D Supplementation on Incident Atrial Fibrillation: A Randomized Clinical Trial. JAMA. 2021;325:1061-73.

Rist PM, Buring JE, Cook NR, et al. Effect of Vitamin D and/or Marine n-3 Fatty Acid Supplementation on Changes in Migraine Frequency and Severity. Am J Med. 2021;134:756-62.

Christen WG, Cook NR, Manson JE, et al. Effect of Vitamin D and ω-3 Fatty Acid Supplementation on Risk of Age-Related Macular Degeneration: An Ancillary Study of the VITAL Randomized Clinical Trial. JAMA Ophthalmol. 2020;138:1280-89.

MacFarlane LA, Cook NR, Kim E, et al. The Effects of Vitamin D and Marine Omega-3 Fatty Acid Supplementation on Chronic Knee Pain in Older US Adults: Results From a Randomized Trial. Arthritis Rheumatol. 2020 Nov;72(11):1836-1844.

Chou SH, Murata EM, Yu C, et al. Effects of Vitamin D3 Supplementation on Body Composition in the VITamin D and OmegA-3 TriaL (VITAL). J Clin Endocrinol Metab. 2021;106:1377-88.

Kang JH, Vyas CM, Okereke OI, et al. Effect of vitamin D on cognitive decline: results from two ancillary studies of the VITAL randomized trial. Sci Rep. 2021;11:23253.

Rist PM, Buring JE, Cook NR, et al. Effect of vitamin D and/or omega‐3 fatty acid supplementation on stroke outcomes: A randomized trial. Eur J Neurol. 2021;28:809-15.

Hahn J, Cook NR, Alexander EK, et al. Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial. BMJ. 2022;376:e066452

LeBoff MS, Chou SH, Murata EM, et al. Effects of Supplemental Vitamin D on Bone Health Outcomes in Women and Men in the VITamin D and OmegA-3 TriaL (VITAL). J Bone Miner Res. 2020;35:883-93.

LeBoff MS, Chou SH, Ratliff KA, et al. Supplemental vitamin D and incident fractures in midlife and older adults. NEJM. 2022;387:299-309.

Kolata G. Study finds another condition that vitamin D pills do not help. The New York Times. July 27, 2022

Jolliffe DA, Holt H, Greenig M, et al. Effect of a test-and-treat approach to vitamin D supplementa...

Vitamin D Part 1: Is the Deficiency Epidemic Real?

Épisode 3

lundi 10 mars 2025 • Durée 01:23:09

Is America really facing an epidemic of vitamin D deficiency? While this claim is widely believed, the story behind it is packed with twists, turns, and some pesky statistical cockroaches. In this episode, we’ll dive into a study on Hawaiian surfers, expose how shifting goalposts can create an epidemic, tackle dueling medical guidelines, and flex our statistical sleuthing skills. By the end, you might wonder if the real deficiency lies in the data.

Statistical topics

dichotomization
normal distribution
standard deviation
researcher biases
conflicts of interest
statistical sleuthing

Methodologic morals

“Arbitrary thresholds make for arbitrary diseases.”
“Statistical errors are like cockroaches: Where there’s one, there’s many.”

Note that all blood vitamin D levels discussed in the podcast are 25-hydroxyvitamin D levels given in units of ng/ml. To convert from ng/ml to nmol/L, use the formula: nmol/L=2.5*ng/ml. For example, a vitamin D level of 30 ng/mL corresponds to 75 nmol/L.

Citations
Dr. Rhonda Patrick: Micronutrients for Health & Longevity. Huberman Lab Podcast. May 1, 2022

Noh CK, Lee MJ, Kim BK, et al. A Case of Nutritional Osteomalacia in Young Adult Male. J Bone Metab. 2013; 20:51-55.

Binkley N, Novotny R, Krueger D, et al. Low vitamin D status despite abundant sun exposure. J Clin Endocrinol Metab. 2007;92:2130-5.

Malabanan A, Veronikis IE, Holick MF. Redefining Vitamin D Insufficiency. Lancet. 1998;351:805-6.

Dawson-Hughes B, Heaney RP, Holick MF, et al. Estimates of optimal vitamin D status. Osteoporos Int. 2005;16:713-6.

Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357:266-81.

Cui A, Xiao P, Ma Y, et al. Prevalence, trend, and predictor analyses of vitamin D deficiency in the US population, 2001-2018. Front Nutr. 2022;9:965376.

Ross AC, Manson JE, Abrams SA, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011;96:53-8.

Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2011;96:1911-30.

Manson JE, Brannon PM, Rosen CJ, et al. Vitamin D deficiency-is there really a pandemic. N Engl J Med. 2016;375:1817-20.

Conti G, Chirico V, Lacquaniti A, et al. Vitamin D intoxication in two brothers: be careful with dietary supplements. J Pediatr Endocrinol Metab. 2014;27:763-7.

Holick, Michael, et al. The UV Advantage. Ibooks, 2004.

Holick, Michael F. The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problems. Penguin Publishing Group, 2011.

Szabo, Liz. Vitamin D, the Sunshine Supplement, Has Shadowy Money Behind It. The New York Times. August 18, 2018.

Lee JM, Smith JR, Philipp BL, Chen TC, Mathieu J, Holick MF. Vitamin D deficiency in a healthy group of mothers and newborn infants. Clin Pediatr. 2007;46:42-4.

Holick MF. Vitamin D deficiency: what a pain it is. Mayo Clin Proc. 2003;78:1457-9.

Passeri G, Pini G, Troiano L, et al. Low Vitamin D Status, High Bone Turnover, and Bone Fractures in Centenarians. J Clin Endocrinol Metab. 2003;88:5109-15.

Armstrong, David. The Child Abuse Contrarian. ProPublica. September 16, 2018.

Irwig MS, Kyinn M, Shefa MC. Financial Conflicts of Interest Among Authors of Endocrine Society Clinical Practice Guidelines. J Clin Endocrinol Metab. 2018;103:4333-38.

Demay MB, Pittas AG, Bikle DD, et al. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2024;109:1907-47.

McCartney CR, McDonnell ME, Corrigan MD, et al. Vitamin D Insufficiency and Epistemic Humility: An Endocrine Society Guideline Communication. J Clin Endocrinol Metab. 2024; 109:1948–54.

See our detailed notes here

Kristin and Regina’s online courses
Demystifying Data: A Modern Approach to Statistical Understanding

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/X

Regina - LinkedIn & ReginaNuzzo.com

Chapters:

(00:00) - Introduction
(02:55) - Sources of Vitamin D
(05:43) - What is Vitamin D & Why Do We Need It?
(07:07) - Vitamin D Deficiency & Rickets
(10:03) - Defining Vitamin D Deficiency – Changing the Goalposts
...

Sugar Sag: Is Your Diet Aging You?

Épisode 8

lundi 19 mai 2025 • Durée 01:08:27

Wrinkles and sagging skin—just normal aging, or can you blame your sweet tooth? We dive into “sugar sag,” exploring how sugar, processed foods, and even your crispy breakfast toast might be making you look older than if you’d said no to chocolate cake and yes to broccoli. Along the way, we encounter statistical adjustment, training and test data sets, what we call “references to nowhere,” plus some cadavers and collagen. Ever heard of an AGE reader? Find out how this tool might offer a sneak peek at your date’s age—and maybe even a clue about his… um… “performance.”

Statistical topics

Training and test sets
Statistical adjustment
Overfitting
Plagiarism
Proper citing practices
References to nowhere

Methodologic morals

“When you plagiarize, you steal the errors too.”
“Overdone statistical adjustment is like overdone photo filters–at a certain point it’s just laughable.”

Citations

Collagen turnover:

Verzijl N, DeGroot J, Thorpe SR, et al.Effect of Collagen Turnover on the Accumulation of Advanced Glycation End Products. JBC. 2000;275:39027-31.

Cadaver study:

Hamlin CR, Kohn RR, Luschin JH. Apparent Accelerated Aging of Human Collagen in Diabetes Mellitus. Diabetes. 1975; 24: 902–904.

AGE Reader

Studies of AGEs and diabetes and health:

Monnier VM, Cerami A. Nonenzymatic browning in vivo: possible process for aging of long-lived proteins. Science. 1981;211:491-3.
Brownlee M, Vlassara H, Cerami A. Nonenzymatic glycosylation and the pathogenesis of diabetic complications. Ann Intern Med. 1984;101:527-37.
Monnier VM, Vishwanath V, Frank KE, et al. Relation between Complications of Type I Diabetes Mellitus and Collagen-Linked Fluorescence. N Engl J Med. 1986;314:403-408.
Monnier VM, Sell DR, Abdul-Karim FW, et al. Collagen browning and cross-linking are increased in chronic experimental hyperglycemia. Relevance to diabetes and aging. Diabetes. 1988;37:867-72.
Monnier VM, Bautista O, Kenny D, et al. Skin collagen glycation, glycoxidation, and crosslinking are lower in subjects with long-term intensive versus conventional therapy of type 1 diabetes: relevance of glycated collagen products versus HbA1c as markers of diabetic complications. Diabetes 1999; 48: 870–80.
Genuth S, Sun W, Cleary P, et al. Glycation and carboxymethyllysine levels in skin collagen predict the risk of future 10-year progression of diabetic retinopathy and nephropathy in the diabetes control and complications trial and epidemiology of diabetes interventions and complications participants with type 1 diabetes. Diabetes. 2005;54:3103-11.
van Waateringe RP, Slagter SN, van Beek AP, et al. Skin autofluorescence, a non-invasive biomarker for advanced glycation end products, is associated with the metabolic syndrome and its individual components. Diabetol Metab Syndr. 2017;9:42.
Kouidrat Y, Zaitouni A, Amad A, et al. Skin autofluorescence (a marker for advanced glycation end products) and erectile dysfunction in diabetes. J Diabetes Complications. 2017;3:108-113.
Fujita N, Ishida M, Iwane T, et al. Association between Advanced Glycation End-Products, Carotenoids, and Severe Erectile Dysfunction. World J Mens Health. 2023;41:701-11.
Uruska A, Gandecka A, Araszkiewicz A, et al. Accumulation of advanced glycation end products in the skin is accelerated in relation to insulin resistance in people with Type 1 diabetes mellitus. Diabet Med. 2019;36:620-625.
Boersma HE, Smit AJ, Paterson AD, et al. Skin autofluorescence and cause-specific mortality in a population-based cohort. Sci Rep 2024;14:19967.

Review article with conflicts of interest:

Draelos ZD. Sugar Sag: What Is Skin Glycation and How Do You Combat It? J Drugs Dermatol. 2024; 23:s5-10.

Clinical study on AGE interrupter cream:

Draelos ZD, Yatskayer M, Raab S, Oresajo C. An evaluation of the effect of a topical product containing C-xyloside and blueberry extract on the appearance of type II diabetic skin. J Cosmet Dermatol. 2009;8:147-51.

The citation trail:

2023 review article: Zgutka K, Tkacz M, Tomasiak, et al. A Role for Advanced Glycation End Products in Molecular Ageing. Int J Mol Sci. 2023; 24: 9881. Sentence: “Interestingly, strict control of blood sugar for 4 months reduced the production of glycosylated collagen by 25%, and low-sugar food prepared by boiling could also reduce the production of AGEs [152].”
Reference 152 is a review article: Cao C, Xiao Z, Wu Y, et al. Diet and Skin Aging-From the Perspective of Food Nutrition. Nutrients. 2020;12:870. Sentence: “However, strict control of blood sugar for four months can reduce the production of glycosylated collagen by 25%, and low-sugar food prepared by boiling can also reduce the production of AGEs [93–95].”
Reference 93 is a review article: Nguyen HP, Katta R. Sugar sag: Glycation and the role of diet in aging skin. Skin Ther Lett. 2015; 20: 1–5. Sentence: “Tight glycemic control over a 4-month period can result in a reduction of glycated collagen formation by 25%.37,38”
Reference 94 and 38 is a review article: Draelos ZD. Aging skin: the role of diet: facts and controversies. Clin Dermatol. 2013;31:701-6. Sentence: “Tighter glycemic control can reduce glycated collagen by 25% in 4 months.” No citation given.
Reference 95 and 37 is a review article: Danby FW. Nutrition and aging skin: Sugar and glycation. Clin. Dermatol. 2010;28: 409–11. Sentence: “...tight glycemic control can drop glycated collagen formation by 25% in 4 months.” No citation given.
The origi...

Hookworms: Can parasites improve your health?

Épisode 7

lundi 5 mai 2025 • Durée 01:08:00

What if you could treat your prediabetes with . . . worms? Regina and Kristin dive into a surprising early-phase clinical trial on hookworm therapy—that’s right, intentionally infecting yourself with parasitic worms—to treat metabolic conditions. They dig into the biological rationale (inflammation, abdominal fat, and gut immunology), the clever study design (hello, Tabasco sauce!), and the statistical chops behind this phase 1B trial (block randomization, missing data, and nonparametric hypothesis tests). Along the way, expect self-experimenting scientists, worm sex, poop analysis, and the world’s nerdiest aphrodisiac: a well-documented protocol.

Statistical topics

Randomized controlled trial (RCT)
Primary and secondary outcomes
Placebos, placebo effect, and nocebo effect
Block randomization
Sample size
Double-blinding
Missing data protocols
Reproducible research
Nonparametric hypothesis testing
Kruskal-Wallis test

Methodological morals

“Walk before you can run. Invest in simple but high-quality Phase I clinical trials.”
“When faced with small samples, you better rank and sum, baby.”

References

Pierce DR, McDonald M, Merone L, et al. Effect of experimental hookworm infection on insulin resistance in people at risk of type 2 diabetes. Nat Commun. 2023;14(1):4503. doi:10.1038/s41467-023-40263-4
Nuzzo, R. What Happens When Scientists Experiment on Themselves? Reader’s Digest. Updated April 16, 2016.
Ethics of self-experimentation
Helminthic Therapy Wiki
Pritchard D. Worming your way to good health [video online]. TEDx Talks. Published November 19, 2013. https://www.youtube.com/watch?v=sm5DcdZbnGA
Chapman PR, Giacomin P, Loukas A, McCarthy JS. Experimental human hookworm infection: a narrative historical review. PLoS Negl Trop Dis. 2021;15(12):e0009908. doi:10.1371/journal.pntd.0009908
Sobotková K, Parker W, Levá J, Růžková J, Lukeš J, Jirků Pomajbíková K. Helminth Therapy - From the Parasite Perspective. Trends Parasitol. 2019;35(7):501-515. doi:10.1016/j.pt.2019.04.009
Zatterale F, Longo M, Naderi J, et al. Chronic Adipose Tissue Inflammation Linking Obesity to Insulin Resistance and Type 2 Diabetes. Front Physiol. 2020;10:1607. Published 2020 Jan 29. doi:10.3389/fphys.2019.01607

Kristin and Regina’s online courses

Demystifying Data: A Modern Approach to Statistical Understanding

Epidemiology and Clinical Research Graduate Certificate Program

Program we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

(02:44) - What happens when scientists experiment on themselves
(06:56) - Mail-order DIY helminthic therapy
(09:26) - Hookworm biology
(15:53) - Inflammation, abdominal fat, immune system, and hookworms
(21:29) - Hookworm therapy clinical trial design
(26:00) - Clinical trial phases deep dive
(31:24) - Interesting placebos (sham surgeries and psychedelics)
(37:33) - Excitement over hookworm trial open data and data protocols
(44:45) - Hookworm trial results
(48:48) - Mood and well-being with hookworms
(53:26) - Effects of hookworms on weight
(56:09) - Nonparametric tests and how they work
(01:02:56) - What the participants did after the study
(01:04:53) - Wrap-up

Alcohol: Are happy hours good for your heart?

Épisode 6

lundi 21 avril 2025 • Durée 01:05:31

Does a daily glass of wine really keep the cardiologist away? It’s a claim we’ve all heard: light to moderate drinking is good for your heart. But is it science or just a convenient excuse for happy hour? In this episode, we dive into the history behind this claim, discuss the challenges of observational studies and statistical adjustment, and explore attempts at randomized trials and natural experiments to get to the bottom of this boozy debate. Grab your drink—or maybe don’t—and join us!

Statistical topics

Statistical Adjustment
Regression
Residual and Unmeasured Confounding
Randomized Trials
Multiple Testing
Outcome Switching
Mendelian Randomization

Methodological morals
“Statistical adjustment cannot erase all confounding.”

“When you can’t experiment on people, let Nature experiment on people.”

Citations

Alcohol and Drinking. Gallup Poll. 2024.
Canada’s Guidance on Alcohol and Health. Canadian Centre on Substance Use and Addiction. 2023.
U.S. Department of Agriculture and U.S. Department of Health and Human Services. 2020 – 2025 Dietary Guidelines for Americans. 2020.
U.S. Department of Agriculture and U.S. Department of Health and Human Services. Alcohol and Cancer Risk: The US Surgeon General's Advisory. 2025.
Mezue K, Osborne MT, Abohashem S, et al. Reduced stress-related neural network activity mediates the effect of alcohol on cardiovascular risk. JACC. 2023;81:2315-25.
McPhillips D, Goodman B. Small amounts of alcohol may turn down stress in the brain, benefiting the heart, new study finds. CNN. June 12, 2023.
Friedman GD, Klatsky AL. Is alcohol good for your health? NEJM. 1993;329:1882-3.
Sainani K. Alcohol and Weight. Allure. July 14, 2010.
Wang LU, Lee IM, Manson JE, et al. Alcohol consumption, weight gain, and risk of becoming overweight in middle-aged and older women. Arch Intern Med. 2010;170:453-61.
Sainani K. Drinking and Weight. Allure. Oct 31, 2008.
Tolstrup JS, Halkjær J, Heitmann BL, et al. Alcohol drinking frequency in relation to subsequent changes in waist circumference. Am J Clin Nutr. 2008;87:957-63.
Rabin RC. Major Study on Drinking Will be Shut Down. New York Times. June 15, 2018.
Mitchell G, Lesch M, McCambridge J. Alcohol industry involvement in the moderate alcohol and cardiovascular health trial. AJPH. 2020;110:485-8.
Gepner Y, Golan R, Harman-Boehm I, et al. Effects of Initiating Moderate Alcohol Intake on Cardiometabolic Risk in Adults With Type 2 Diabetes: A 2-Year Randomized, Controlled Trial. Ann Intern Med. 2015;163:569-79.
Slade E, Drysdale H, Goldacre B, et al. Discrepancies between prespecified and reported outcomes. Ann Intern Med. 2016;164:374.
Biddinger KJ, Emdin CA, Haas ME, et al. Association of habitual alcohol intake with risk of cardiovascular disease. JAMA Netw Open. 2022;5:e223849.

Page with more details on the CASCADE trial

Kristin and Regina’s online courses:

Program that we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Introduction
(03:00) - Drinking habits in America
(04:13) - New Canadian drinking guidelines
(07:51) - Definition of light-to-moderate drinking
(08:43) - Risks and benefits of light-to-moderate drinking
(11:37) - History of the heart health claim
(18:34) - Problems with observational studies
(22:40) - Statistical adjustment
(25:39) - Residual and unmeasured confounding
(31:19) - Overconfidence in observational studies
(35:16) - Randomized trials of alcohol
(36:32) - Canceled NIH randomized trial of alcohol
(41:42) - The CASCADE randomized trial of wine
(43:18) - The problem of multiple testing
(47:56) - Outcome switching
(49:32) - Mendelian randomization
(59:04) - Mendelian randomization studies of alcohol and heart disease
(01:03:09) - Wrap-up

The Red Dress Effect: Are women in red sexier?

Épisode 5

lundi 7 avril 2025 • Durée 01:08:45

Wear red and drive men wild with lust – or so says scientific research on color’s role in human mating. But can a simple color swap really boost a woman’s hotness score? In this episode, we delve into the evidence behind the Red Dress Effect, from a controversial first study in college men to what the latest research says about who this trick might work for (and who it might not). Along the way we encounter red monkey butts, old-Internet websites, the Winner’s Curse in scientific research, adversarial collaborations, and why size (ahem, sample size) really does matter.

Statistical topics

Reproducibility crisis in psychology
Sample size
Selection bias
Winner’s curse
Cohen’s d standardized effect size
Adversarial collaboration
Meta-analysis
Preregistration
Publication bias
Statistical moderators

Methodological morals

“The smaller the sample, the flashier the result, the less you should trust it.”

“Good scientists learn from their statistical mistakes and fix them.”

References

Clarke, G. How to Be Sexy: 7 Weird (But True) Rules of Attraction. Allure. January 23, 2013.
Nuzzo, R. Vying for a soul mate? Psych out the competition with science. Los Angeles Times. December 8, 2008.
Vying for a Soul Mate on the Today Show, December 30, 2008.
Elliot, A.J. and Niesta, D. Romantic red: red enhances men's attraction to women. Journal of personality and social psychology. 2008; 95: 1150 – 1164.
Lehrer, J. The Truth Wears Off. The New Yorker, December 5, 2010.
MacMahon, B., Yen, S., Trichopoulos, D., Warren, K. and Nardi, G. Coffee and cancer of the pancreas. New England Journal of Medicine. 1981; 304: 630-633.
Ioannidis, J.P. Why most published research findings are false. PLoS medicine. 2005; 2(8), e124
Lehmann, G.K., Elliot, A.J. and Calin-Jageman, R.J. Meta-analysis of the effect of red on perceived attractiveness. Evolutionary Psychology. 2018; 16: 1474704918802412.
Pazda, A.D., Thorstenson, C.A. and Elliot, A.J. The effect of red on attractiveness for highly attractive women. Curr Psychol. 2023; 42: 8066–8073

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding

Epidemiology and Clinical Research Graduate Certificate Program

Chapters

(00:00) - Introduction
(06:04) - Red Dress Effect on TV
(10:01) - Red Monkey Butts
(12:56) - 2008 Study on Romantic Red
(16:04) - HotOrNot.com
(20:10) - 2008 Study Results
(25:10) - Cohen’s d Standardized Effect Size
(30:52) - Problems with Small Sample Sizes
(34:12) - Winner’s Curse and Publication Bias
(38:40) - Reproducibility Crisis
(44:03) - Adversarial Collaboration
(49:01) - Meta-Analysis and Pre-Registration
(55:23) - Adversarial Discussion Sections and Updates
(01:02:55) - Latest Red Study
(01:06:26) - Wrap-Up

Dating Wishlists: Are we happier when we get what we want in a mate?

Épisode 12

lundi 14 juillet 2025 • Durée 01:05:31

Loyal, funny, hot — you’ve probably got a wish list for your dream partner. But does checking all your boxes actually lead to happily ever after? In this episode, we dive into a massive global study that put the “ideal partner” hypothesis to the test. Do people really know what they want, and does getting it actually make them happier? We explore surprising statistical insights from over 10,000 romantics in 43 countries, from mean-centering and interaction effects to the good-catch confounder. Along the way, we dig into dessert metaphors, partner boat-count regression models, and the one trait that people say doesn’t matter — but secretly makes them happiest.

Statistical topics

Regression
Random Slopes and Intercepts (Random Effects) in Regression
Standardized Beta Coefficients in Regression
Interaction Effects in Regression
Mean Centering
Exploratory Analyses

Methodological morals

“Good science bares it all.”

“When the world isn't one size fits all, don't fit just one line; use random slopes and intercepts.”

References

Eastwick PW, Sparks J, Finkel EJ, Meza EM, Adamkovič M, Adu P, Ai T, Akintola AA, Al-Shawaf L, Apriliawati D, Arriaga P, Aubert-Teillaud B, Baník G, Barzykowski K, Batres C, Baucom KJ, Beaulieu EZ, Behnke M, Butcher N, Charles DY, Chen JM, Cheon JE, Chittham P, Chwiłkowska P, Cong CW, Copping LT, Corral-Frias NS, Ćubela Adorić V, Dizon M, Du H, Ehinmowo MI, Escribano DA, Espinosa NM, Expósito F, Feldman G, Freitag R, Frias Armenta M, Gallyamova A, Gillath O, Gjoneska B, Gkinopoulos T, Grafe F, Grigoryev D, Groyecka-Bernard A, Gunaydin G, Ilustrisimo R, Impett E, Kačmár P, Kim YH, Kocur M, Kowal M, Krishna M, Labor PD, Lu JG, Lucas MY, Małecki WP, Malinakova K, Meißner S, Meier Z, Misiak M, Muise A, Novak L, O J, Özdoğru AA, Park HG, Paruzel M, Pavlović Z, Püski M, Ribeiro G, Roberts SC, Röer JP, Ropovik I, Ross RM, Sakman E, Salvador CE, Selcuk E, Skakoon-Sparling S, Sorokowska A, Sorokowski P, Spasovski O, Stanton SCE, Stewart SLK, Swami V, Szaszi B, Takashima K, Tavel P, Tejada J, Tu E, Tuominen J, Vaidis D, Vally Z, Vaughn LA, Villanueva-Moya L, Wisnuwardhani D, Yamada Y, Yonemitsu F, Žídková R, Živná K, Coles NA. A worldwide test of the predictive validity of ideal partner preference matching. J Pers Soc Psychol. 2025 Jan;128(1):123-146. doi: 10.1037/pspp0000524
Love Factually Podcast: https://www.lovefactuallypod.com/

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding