What is True? Rating Evidence

Everyday we are inundated with new and often contradictory “breaking medical research.” Today, “Aspirin prevent melanoma.” But just 1 month prior “Aspirin doubles incidence of Macular Degeneration”. News outlets using sensational phrases like “Mammogram cause more harm than good” or eye catching “Mammogram done at earlier age catches more invasive breast cancer” make us think we should do something because it will better our health. Let’s face it, we are all busy and in this 24/7 always on information world, we hear something is good for us, so we want to try it.

How do you clear the clutter and educate yourself so you only pay attention to actual important news. First verify everything you hear. Ask a trusted doctor – shoot us a question on facebook.com, or visit reputable online sites like mayoclinic.org, medlineplus.gov, or Harvard’s Inteliheath. Even webmd.com, which does takes money from pharmaceutical companies, is still a good place to start.

But when evaluating research, that’s a needs a little bit of explanation. Not all research is the same, and not all study results deserve equal merit. The proof, or evidence as I refer to it, is graded based on the type of study done. In general, the more people enrolled in the trial and longer duration, the stronger the evidence.

Evidence in descending order of quality,

  1. Meta-analysis of Randomized Control Trials
  2. Randomized Control Trial with Cross Over Design. (RCT)
  3. Observational studies like cohort and case control studies
  4. Cross-Sectional studies aka “surveys”
  5. Non-evidence-based expert opinion or clinical experience
  6. Your Neighbor or what I call “N of 1.” A person who tells you, try this, it cured me, or don’t take that, it gave me joint pain

Believe it or not, expert opinion is the weakest form of evidence. And it ranks right above your neighbor giving you medical advice.

“N of 1” is something we are all guilty of putting a lot of misguided value in. But scientifically, it’s the worse most uninformed way to make a decision about your health. To put N of 1 into context, if I gave you a hot stock tip, would you risk your money just because I said so. Probably not.

So the next time you hear Good Morning America proclaim “Aspirin prevents Melanoma”, go online and look at the type of study done to see if it’s worth paying attention to.

Be informed, be empowered.

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