Notes on Evidence-Based Medicine and Data Transparency
What Epidemiology Is
- Epidemiology is the science of how we know in the real world whether something is good for you or bad for you.
- It helps explain why sensational headlines (e.g., about coffee, Wi‑Fi, or olive oil) can be inconsistent or misleading.
- The aim is to unpick the evidence behind claims; this is socially useful and a powerful explanatory tool.
Core Idea: Evidence-Based Medicine (EBM)
- EBM = critical appraisal of evidence to determine what really helps or harms people.
- It relies on data, not authority or prestige.
- Academic critique (e.g., Q&A in journals) is normal and valuable.
- Authority alone is unreliable in science; reasons matter more than titles.
- Example: Gillian McKeith (TV diet guru) with an unaccredited PhD and dubious credentials; illustrates why credentials aren’t enough.
From Headlines to Proper Science
- Red wine and breast cancer: lab findings (enzyme behavior with grape compounds) do not translate to personal risk reduction; alcohol increases breast cancer risk.
- Observational claims (olive oil + vegetables reducing wrinkles) reflect associations, not causation; confounding factors matter.
- What we need: well-conducted human studies, ideally trials, to establish causation.
Observational vs Experimental Evidence
- Observational studies: snapshot associations; prone to confounding (socioeconomic status, lifestyle).
- Trials (randomized, controlled) are the gold standard for establishing causation.
Trials, Randomization, and Placebo
- A well-designed trial compares a new treatment to the best available alternative, not just to nothing.
- The fish oil trial (3{,}000 children) lacked a proper control group and was vulnerable to placebo effects and natural maturation.
- Placebo effect: beliefs and expectations can change outcomes; two sugar pills can outperform one; even a saltwater injection can outperform a dummy pill.
- Trials must be properly controlled to attribute effects to the treatment.
Distortion Tactics in Evidence Communication
- Media and marketers can distort evidence; misreport, cherry-pick, or oversimplify.
- Industry trials use similar tricks with slightly more sophistication, but still aim to shape outcomes.
- Key idea: control groups, appropriate comparators, and realistic dosing are essential for fair trials.
Publication Bias and Missing Data
- Industry-funded trials are more likely to report positive results, but negative data are often missing.
- The missing data problem skews the apparent effectiveness of treatments.
- A top-priority problem: having access to all trial data is essential for accurate judgments.
Detecting Missing Data and Bias
- Funnel plots: graphs that show trial size vs. effect; asymmetry suggests publication bias or missing small negative trials.
- Data withholding can be inferred from statistical patterns or stories of withheld trials.
- Reboxetine example: 76% of trials were withheld from clinicians and patients.
Data Transparency and Ethics in Medicine
- About half of antidepressant trial data have been withheld historically; similar issues exist with other medications.
- The Nordic Cochrane Group and European agencies have struggled to obtain complete data for systematic reviews.
- Tamiflu data access illustrates large-scale implications for policy and public health.
- Ethical problem: decisions cannot be made without all information.
The Right Standard: Sunshine as Disinfectant
- Sunlight (data transparency) is the best disinfectant for science.
- Problems persist due to a culture of tediousness around data sharing.
- Actionable takeaway: promote full data availability and rigorous, independent analysis to improve real-world decisions.
Takeaways for Quick Recall
- Epidemiology helps verify real-world health claims beyond sensational headlines.
- Prioritize evidence over authority; seek randomized, placebo-controlled trials with appropriate comparators.
- Be wary of observational studies and confounding factors.
- Recognize and account for placebo effects in trial design.
- Be vigilant about publication bias and data withholding; demand complete data access.
- Use transparency and independent reviews (e.g., Cochrane-style analyses) to inform decisions.