September 1, 2015

Reproducing Study Results: Why It’s Hard, and Why It’s Important

An article in the August 27 edition of The New York Times reports that the results of scientific studies may not be as dependable – or at least as reproducible – as we might think.  

Hundreds of millions of people – doctors and patients around the world – use those studies to make important healthcare decisions. This blog regularly features recent study results.

In a new analysis called the Reproducibility Project, University of Virginia psychologist Brian Nosek recruited a team of 250 researchers four years ago. They identified 100 studies published in 2008 in three of psychology’s top journals (Psychological Science, the Journal of Personality and Social Psychology, and the Journal of Experimental Psychology: Learning, Memory, and Cognition).

Next, in close collaboration with those studies’ original authors, Nosek’s team undertook the daunting task of reproducing the results.

Almost 2/3 of All Study Results Didn't Hold Up
Their finding? Of the 100 studies, 35 held up, while 62 did not, according to a statistical measure of the likelihood that a result did not occur by chance. The remaining three studies were excluded because statistical significance wasn’t clear.

The team asked original study authors for guidance in replicating study design, methodology, and materials. In most cases, Nosek’s replications involved more subjects than the original studies, thus giving his own results more statistical heft.

The research team also measured whether the original research groups’ expertise or academic affiliations – their “prestige” – had any effect on the likelihood that results would hold up. They didn’t. Only one factor seemed to matter: the robustness of the original finding.

August 31, 2015

God Save the "New York Times"

Every Sunday morning for years, I've stepped out the front door to pick up my New York Times and Washington Post from the sidewalk, yard, or curb... depending on the delivery driver's aim.

During Ben Bradlee's 26 years as editor, the Post increasingly challenged the Times as the best in American journalism. No more.

Digital Journalism
The Times is considered a top innovator with web journalism, particularly multimedia and interactive data. It recently announced that it had reached a new milestone: one million digital-only subscribers.

As a subscriber to the Sunday-only Times, I can access its many digital offerings. Here's one example.

The Times Weekly Wrap
Every Saturday, I receive an email with "The Times Weekly Wrap," which "takes readers behind the scenes of the New York Times newsroom to show how its journalists work and how decisions are made."

Sounds boring, and sometimes it is. But then I find something like last week's posting, "Where Are U Now That I Need You?" -- the name of the million-selling single by Skrillex and Diplo with Justin Bieber. The song, which Times music critic Jon Pareles calls "four minutes of high-tech bliss," was the subject of a series of articles that ran last week about how pop music is made today.

I have little interest in pop music, but I really liked the song:

August 27, 2015

Two TED Talks Related to Upcoming Discussion of Brain Healing and Parkinson's

It's 9pm Thursday, and I'm just getting around to writing today's post. So, looking for something quick and easy, I came up with these two TED talks. I had saved them because they relate to a post I intend to run next week on neural plasticity (the brain's ability to heal itself) and Parkinson's.

First comes the highly popular talk by the positive psychology expert Shawn Achor. Most people believe that once they land that long-awaited promotion, make more money, get their kids into the right schools, lose a few pounds or find a meaningful relationship, then they'll be happy. But based on recent discoveries in the fields of positive psychology and neuroscience, Achor says this formula has it backwards. As it turns out, happiness actually fuels success, not the other way around.

Achor's TED talk has been viewed by millions. It's a bit too slick and cute for my taste. Much more to my liking is this talk by Dr. Libby McGugan, an emergency physician from Glascow, Scotland. When I looked at the video, YouTube showed 1,682 views. You go, girl!

August 26, 2015

Another Call for "Less Medicine, More Health"

That's the title of an excellent book by Dr. H. Gilbert Welch.

An internist at the White River Junction Veterans Administration Medical Center in Vermont, and a researcher at the Dartmouth Institute, Welch presents an informal, witty, and wise argument that less "care" may result in better health and less harm to the patient.

He systematically debunks seven widely held assumptions about the value of more tests and treatments. His book is "more narrative, with fewer numbers, and perhaps most importantly, no scary tabular and graphical data and no superscript references."

The Seven Assumptions
Welsh devotes a chapter to each assumption, and he ends each chapter with a "prescription" of simple, actionable strategies to avoid too much medical care.

August 25, 2015

Nine Risk Factors for Alzheimer's

An article published online last week in the Journal of Neurology, Neurosurgery & Psychiatry describes nine risk factors for Alzheimer’s disease (AD). The data from this study suggests that these nine factors contribute to two thirds of all AD cases worldwide.

What’s more, these remarkably varied risk factors are all modifiable; there is something we can do about them. That’s important because there is no cure for the disease that affects over 44 million people around the world… and hundreds of millions of family members and caregivers.

Eager to study the complexity of AD development, researchers in China and California undertook a monumental enterprise: reviewing all relevant studies published in English from 1968 to July, 2014 (in PubMed and the Cochrane Database of Systematic Reviews).

From the 16,906 studies they reviewed, the scientists identified 323 that offered data they could include in their own study. From those 323 studies, the team found 93 separate possible AD risk factors that involved more than 5,000 people.

Because they were especially concerned with the causes – the complexity – of dementia development, the researchers pooled the metadata from all the applicable studies and evaluated the evidence based on its strength.

First, the Evidence
The team found “grade 1 level evidence” (evidence obtained from at least one properly designed randomized controlled trial) that the following medical exposures were protective against dementia development: 
  • The female hormone estrogen
  • Statins (cholesterol-lowering drugs)
  • Drugs to lower high blood pressure
  • NSAIDS (non-steroidal anti-inflammatory drugs)
The scientists found the same quality of evidence – protective against AD – for these dietary exposures:
  • Folate (a water-soluble B vitamin naturally present in some foods, added to others, and available as a dietary supplement)
  • Vitamins C and E
  • Coffee

On the other hand, the scientists found a strong association between the following and a heightened risk of developing AD: