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[Repost] Yay for BMJ journal news release for caveats about observational study!

An example of a heart attack, which can occur ...

An example of a heart attack, which can occur after the use of a performance-enhancing drug. (Photo credit: Wikipedia)

Yay for BMJ journal news release for caveats about observational study!.

From the 19 August 2014 post at HealthNewsReview

I’ve criticized them many times, so now it’s time to salute them.

And let’s hope the news release writers for BMJ journals continue this practice.

This week, in a news release about a paper in one of the journals published by the BMJ, the Journal of Epidemiology & Community Health, was this caveat:

“This is an observational study so no definitive conclusions can be drawn about cause and effect, and the researchers admit that some potentially important risk factors, such as family history of heart disease/stroke and genetic influences were not known.”

Such a statement of limitations has been missing many times in past news releases from/about BMJ journals.

I can’t see everything, so I may have missed other good examples in the past.

Here is the full text of the news release in question:

Good neighbours and friendly local community may curb heart attack risk

Might extend social support network which is also linked to lower cardiovascular disease risk, say researchers

[Perceived neighbourhood social cohesion and myocardial infarction Online First doi 10.1136/jech-2014-204009]

Having good neighbours and feeling connected to others in the local community may help to curb an individual’s heart attack risk, concludes research published online in the Journal of Epidemiology & Community Health.

Current evidence suggests that the characteristics of an area in which a person lives can negatively affect their cardiovascular health. This includes, for example, the density of fast food outlets; levels of violence, noise, and pollution; drug use; and building disrepair.

But few studies have looked at the potential health enhancing effects of positive local neighbourhood characteristics, such as perceived neighbourhood social cohesion, say the authors.

They therefore tracked the cardiovascular health of over 5000 US adults with no known heart problems over a period of four years, starting in 2006. Their average age was 70, and almost two thirds were women and married (62%).

All the study participants were taking part in the Health and Retirement Study, a nationally representative study of American adults over the age of 50, who are surveyed every two years.

In 2006 participants were asked to score on a validated seven point scale how much they felt part of their local neighbourhood; if they felt they had neighbours who would help them if they got into difficulty; whether they trusted most people in the area; and felt they were friendly.

Potentially influential factors, such as age, race, gender, income, marital status, educational attainment, outlook and attitude, social integration, mental health, lifestyle, weight, and underlying health issues, such as diabetes and high blood pressure, were all taken into account.

During the four year monitoring period, 148 of the 5276 participants (66 women and 82 men) had a heart attack.

Analysis of the data showed that each standard deviation increase in perceived neighbourhood social cohesion was associated with a 22% reduced risk of a heart attack. Put another way, on the seven-point scale, each unit increase in neighbourhood social cohesion was associated with a 17% reduced risk of heart attack.*

This association held true even after adjusting for relevant sociodemographic, behavioural, biological, and psychosocial factors, as well as individual-level social support.

The researchers say their findings echo those of other studies which have found a link between well integrated local neighbourhoods and lower stroke and heart disease risk.

This is an observational study so no definitive conclusions can be drawn about cause and effect, and the researchers admit that some potentially important risk factors, such as family history of heart disease/stroke and genetic influences were not known. But a strong social support network of friends and family has been linked to better health, so friendly neighbourhoods might be an extension of that, they say.

“Perceived neighbourhood social cohesion could be a type of social support that is available in the neighbourhood social environment outside the realm of family and friends,” they write.

And tight-knit local communities may help to reinforce and ‘incentivise’ certain types of cohesive behaviours and so exclude antisocial behaviours, they suggest.

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October 15, 2014 Posted by | Medical and Health Research News | , , , , , , | Leave a comment

[Reblog] Misleading BMJ news releases may be one reason journalists report on more observational studies

From the 24 January 2014 post at TheHealthNewsReview Blog  by Gary Schwitzer

[At least 16 comments on this post, click on the link above to read them]

Just a few days ago, a paper in the journal PLoS One, “Media Coverage of Medical Journals: Do the Best Articles Make the News?” showed how journalists are more likely to report on observational studies than on randomized clinical trials.  The authors suggest this shows a systematic bias to report on weaker evidence.

And here’s one reason why that may happen.

This week the BMJ sent out a news release on a paper from the Annals of the Rheumatic Diseases, one of the specialist journals it publishes. And I’ve been waiting for days to address it – waiting for the journal’s embargo time to pass so that I’m not violating that sacred trust.

The headline of the news release:  HRT cuts risk of repeat knee/hip replacement surgery by 40%.

 

Nope.  Sorry, BMJ news release writers.  That’s an overstatement, to be kind.  An inaccuracy, to be accurate. That’s not what the study showed, because it wasn’t equipped to show that anything “cut risk.”  Proof of cutting risk would be proof of cause and effect.  And the observational study in question can’t do that.

Don’t blame the authors of the journal article. They didn’t use cause-and-effect language.  They concluded: “HRT is associated with an almost 40% reduction.”  (My emphasis added.) That’s the way you describe the results of an observational study. That’s what we try to teach journalists and the public with a primer that’s been on our site for years. Maybe the BMJ should have its news release writers read it.

The researchers went even further, for any writer – journal news release writers included – who bothered to read the study.  The research team wrote: “The main limitation of this study is its observational nature.”

To be clear, this was a large study with long followup.  This could be a head-turner in medical circles.

But it still is what it is – a study that can only show statistical association.

And association ≠ causation.

We’ve written about this problem with BMJ news releases in the past, and will continue to do so until they get it right.  Past examples:

As I wrote in one of these posts:  Journals could help lift all ships – or they can (and sometimes do) help us all drown in a daily tsunami of global miscommunication about health news.

 

 

 

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January 28, 2014 Posted by | Medical and Health Research News | , , , , , , , , , | Leave a comment

[Reblog] Nuts and death – journal animated video explanation

From the 22 November post at HealthNewsReview.blog

You probably saw, read, or heard about news of an observational study in the New England Journal of Medicine pointing to a statistical association between nut consumption and lower death rate.  Larry Husten did a good job explaining the study on Forbes.com.

The NEJM itself posted a YouTube video that had journal editor Jeffrey Drazen’s voice over an animated explanation.  I hadn’t seen such NEJM videos before.  Take a look. Drazen ends:  “I would be nuts to think that eating nuts alone would add years to my life.”

I wish I had that kind of budget. Frankly, I wish I had any budget.

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Comments

Ellen Goldbaum posted on November 22, 2013 at 11:37 am

Thank you for posting this wonderful video! It was everything a press release should be but so much more enjoyable! To your point about budgets, even those of us who work for large institutions are wondering, how did NEJM make that video, how much personpower and money does it take? curious.

Reply

Brad F posted on November 22, 2013 at 8:26 pm

they ript off Blank on Blank
http://blankonblank.org/pbs/

 

December 8, 2013 Posted by | Nutrition, Uncategorized | , , , , , | Leave a comment

Unpublished trial data ‘violates an ethical obligation’ to study participants, say researchers

Flowchart of four phases (enrollment, interven...

Flowchart of four phases (enrollment, intervention allocation, follow-up, and data analysis) of a parallel randomized trial of two groups, modified from the CONSORT 2010 Statement Schulz KF, Altman DG, Moher D; for the CONSORT Group (2010). “CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials”. BMJ 340 : c332. doi:10.1136/bmj.c332. PMC 2844940. PMID 20332509 . . (Photo credit: Wikipedia)

 

From the 29 October 2013 British Medical Journal press release

 

Study finds almost 1 in 3 large clinical trials still not published 5 years after completion

Almost one in three (29%) large clinical trials remain unpublished five years after completion. And of these, 78% have no results publicly available, finds a study published on bmj.com today.

This means that an estimated 250,000 people have been exposed to the risks of trial participation without the societal benefits that accompany the dissemination of their results, say the authors.

They argue that this “violates an ethical obligation that investigators have towards study participants” and call for additional safeguards “to ensure timely public dissemination of trial data.”

Randomized clinical trials are a critical means of advancing medical knowledge. They depend on the willingness of people to expose themselves to risks, but the ethical justification for these risks is that society will eventually benefit from the knowledge gained from the trial.

But when trial data remain unpublished, the societal benefit that may have motivated someone to enrol in a study remains unrealized.

US law requires that many trials involving human participants be registered – and their results posted – on the largest clinical trial website ClinicalTrials.gov. But evidence suggests that this legislation has been largely ignored.

So a team of US-based researchers set out to estimate the frequency of non-publication of trial results and, among unpublished studies, the frequency with which results are unavailable in theClinicalTrials.gov database.

They searched scientific literature databases and identified 585 trials with at least 500 participants that were registered with ClinicalTrials.gov and completed prior to January 2009. The average time between study completion and the final literature search (November 2012) was 60 months for unpublished trials.

Registry entries for unpublished trials were then reviewed to determine whether results for these studies were available in the ClinicalTrials.gov results database.

Of 585 registered trials, 171 (29%) remained unpublished. Of these, 133 (78%) had no results available in ClinicalTrials.gov. Non-publication was more common among trials that received industry funding (32%) than those that did not (18%).

“Our results add to existing work by showing that non-publication is an important problem even among large randomized trials,” say the authors. Furthermore, the sponsors and investigators of these unpublished trials infrequently utilize the ClinicalTrials.gov results database.

The lack of availability of results from these trials “contributes to publication bias and also constitutes a failure to honor the ethical contract that is the basis for exposing study participants to the risks inherent in trial participation,” they add. “Additional safeguards are needed to ensure timely public dissemination of trial data,” they conclude.

 

 

 

 

 

 

October 30, 2013 Posted by | Medical and Health Research News | , , , , , | Leave a comment

   

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