Posts filed under Medical news (325)

March 14, 2016

Dementia and rugby

Dylan Cleaver has a feature story in the Herald on the Taranaki rugby team who won the Ranfurly Shield in 1964. Five of the 22 have been diagnosed with dementia. Early on in the process he asked me to comment on how surprising that was.

The key fact here is 1964: the five developed dementia fairly young, in their 60s and early 70s. That happens even in people who have no family history and no occupational risks, as I know personally, but it’s unusual.

I couldn’t find NZ data, but I did find a Dutch study (PDF, Table 3) estimating that a man who is alive and healthy at 55 has a 1.5% risk of diagnosed dementia by 70 and 3.2% by 75. There’s broadly similar data from the Framingham study in the US.   The chance of getting 5 or more out of 22 depends on exact ages and on how many died earlier of other causes, but if these were just 22 men chosen at random the chance would be less than 1 in 10,000 — probably much less.  People who know about rugby tell me the fact they were all in the back line is also relevant, and that makes the chance much smaller.

There are still at least two explanations. The first, obviously, is that rugby — at least as played in those days — caused similar cumulative brain damage to that seen in American football players. The second, though, is that we’re hearing about the 1964 Taranaki team partly because of the dementia cases — there wouldn’t have been this story if there had only been two cases, and there might have been a story about some other team instead. That is, it could be a combination of a tragic fluke and the natural human tendency to see patterns.  Statistics is bad at disentangling these; the issue crops up over and over again in cancer surveillance.

In the light of what has been seen in the US, I’d say it’s plausible that concussions contributed to the Taranaki cases.  There have already been changes to the game to reduce repeated concussions, which should reduce the risk in the future. There is also a case for more systematic evaluation of former players, to get a more reliable estimate of the risk, though the fact there’s nothing that can currently be done about it means that players and family members need to be involved in that decision.

March 7, 2016

A good source of iron

Stuff has a story under the lead

Now that it’s autumn, flu season isn’t far off and there’s plenty you could be doing in the kitchen to give your body that extra oomph for the cold months ahead.

Sadly they don’t mean making a phone call to book a flu vaccine shot: they have a list of herbs and spices with unsupported health claims.

Take the first, cinnamon.  Stuff says “It is high in antioxidants, is an anti-inflammatory and has an effect in lowering blood sugar.”  The  National Center for Complementary and Integrative Health , who are about as sympathetic as you can get to this sort of thing “High-quality clinical evidence (i.e., studies in people) to support the use of cinnamon for any medical condition is generally lacking. An analysis of five clinical trials concluded that cinnamon does not appear to affect factors related to diabetes and heart disease.”

Or, for a total failure to do arithmetic, saffron. Stuff says “It is a good source of vitamins, magnesium and iron.” Now, it’s true that saffron is high in nutrients for its weight. A mere 100g of saffron will supply about two-thirds of your daily iron and magnesium, and substantial amounts of vitamins C and B-6. By weight, it does better than spinach. But the typical serving of saffron is a small fraction of a gram, with nutrient contents that would round to zero in any sensible display.

Following the lines of previous StatsChat food advice, I think the photo caption  just needs a bit of editing: “Herbs and spices are an easy way to add healthy elements  flavour to your diet.

(via Mark Hanna and Bart Janssen)

February 29, 2016

‘Cure’ exaggeration

A Herald headline says “Dementia cure just five years away – world expert“. That’s even worse than the Telegraph headline for the original piece “Dementia cure may be just five years away, says world expert“.

The ‘world expert’ is Dennis Gillings, an expert in clinical trials, who is the G8 ‘World Dementia Envoy’, so his opinions are worth listening to. What he says doesn’t really support the headline.

Dr Gillings… said progress was being made on treatments that might halt or reverse the progress of dementia, with some kind of brain training used to help rebuild lost neural pathways.


scientists increasingly believed it had been a mistake to treat dementia as one disease, saying it was likely that breakthroughs would come from targeting subtypes of the condition.


Saluting recent British investment in science, and the creation of a 150 million Dementia Research Institute, he said that, none the less, breakthroughs were more likely in the US, which put more money into research

If a cure was actually going to be available in five years you would have heard about its success in early clinical trials already. He’s talking about making scientific progress within five years to identify a cure, with breakthroughs still needed.

January 25, 2016

Hangover cure?

“The ‘kudzu’ could cure your hangover”, says the Herald (from the Daily Mail)

We’ve had stories based on unpublished research before. This one is a bit special, because the ‘unpublished research’ is a BBC television programme that won’t be shown for a few days (or, at all, in NZ). And because it didn’t study hangovers or people with hangovers.

The BBC programme is apparently going to report a placebo-controlled crossover trial of how much free booze people drank when they had taken kudzu root extract or a dummy pill — they say they saw a 20% difference. The design is a good one, and given the general theme of the show there probably isn’t much risk of publication bias. Having a reasonably good design fits with seeing a benefit that’s only about half of what was seen in earlier US research.

The big problems with the BBC study are that it’s probably small (the stories don’t say) and doesn’t (so far)give any idea of the uncertainty in the 20% reduction, and that open-bar drinking in a television science experiment may be importantly different from the sort of drinking they’d like to decrease.

As science, the BBC study might actually be ok. But reducing alcohol consumption by 20%, if it does, is unlikely to have a big impact in preventing hangovers. And there is not the slightest suggestion in the research that kudzu root would work as a hangover cure.



January 21, 2016

Mining uncertainty

The FDA collects data on adverse events in people taking any prescription drugs. This information is, as it should be, available for other uses. I’ve been involved in research using it.

The data are also available for less helpful purposes. As Scott Alexander found,  if you ask Google whether basically anything could cause basically anything, there are companies that make sure Google will return some pages reporting that precise association.  And, as he explains, this is serious.

For example, I tried “Adderall” and “plantar fasciitis” as an implausible combination and got 4 hits based on FDA data. And “Accutane” and “plantar fasciitis”, and “Advair” and “plantar fasciitis”, and “acyclovir” and “plantar fasciitis”. Then I got bored.

It’s presumably true that there are people who have been taking Adderall and at the same time have had plantar fasciitis. But given enough patients to work with, that will be true for any combination of drug and side effect. And, in fact, the websites will happily put up a page saying there are no reported cases, but still saying “you are not alone” and suggesting you join their support group.

These websites are bullshit in the sense of philosopher Harry Frankfurt: it is irrelevant to their purpose whether Adderall really causes plantar fasciitis or not. They make their money from the question, not from the answer.


(via Keith Ng)

January 19, 2016

Rebooting your immune system?

OneNews had a strange-looking story about multiple sclerosis tonight, with lots of footage of one British guy who’d got much better after treatment, and some mentions of an ongoing trial. With the trial still going on, it wasn’t clear why there was publicity now, or why it mostly involved just one patient.

I Google these things so you don’t have to.

So. It turns out there was a new research paper behind the publicity. There is an international trial of immune stem cell transplant for multiple sclerosis, which plans to follow patients for five years after treatment. The research paper describes what happened for the first three years.

As the OneNews story says, there has been a theory for a long time that if you wipe out someone’s immune system and start over again, the new version wouldn’t attack the nervous system and the disease would be cured. The problem was two-fold. First, wiping out someone’s immune system is an extraordinarily drastic treatment — you give a lethal dose of chemotherapy, and then rescue the patient with a transplanted immune system. Second, it didn’t work reliably.

The researcher behind the current trial believes that the treatment would work reliably if it was done earlier — during one of the characteristic remissions in disease progress, rather than after all else fails. This trial involves 25 patients, and so far the results are reasonably positive, but three years is really to soon to tell whether the benefits are worth the treatment. Even with full follow-up of this uncontrolled study it probably won’t be clear exactly who the treatment is worthwhile for.

Why the one British guy? Well,

The BBC’s Panorama programme was given exclusive access to several patients who have undergone the stem cell transplant.

The news story is clipped from a more in-depth current-affairs programme. That BBC link also shows a slightly worrying paranoid attitude from the lead researcher

He said: “There has been resistance to this in the pharma and academic world. This is not a technology you can patent and we have achieved this without industry backing.”

That might explain pharma, but there’s no real reason for the lack of patents to be a problem for academics. It’s more likely that doctors are reluctant to recommend ultra-high-dose chemotherapy without more concrete evidence. After all, it was supposed to work for breast cancer and didn’t, and it was theorised to work for HIV and doesn’t seem to. And at least in the past it didn’t work reliably for multiple sclerosis.

All in all, I think the OneNews story was too one-sided given the interim nature of the data and lack of availability of the treatment.  It could also have said a bit more about how nasty the treatment is.  I can see it being fine as part of a story in a current affairs programme such as Panorama, but as TV news I think it went too far.

January 18, 2016

Supplement pushing

The Herald has a Daily Mail story about vitamin D for making you generally feel better. It’s not so long ago that the NZ media had a lot of less supportive coverage on vitamin D — Ian Reid, Mark Bolland, and Andrew Grey won the Prime Minister’s Science Prize last year for their work showing that calcium and vitamin D aren’t all they’re cracked up to be.

The story does have some new evidence.

In the study, by a medical team in Edinburgh, volunteers were asked to cycle for 20 minutes. They were then given either a placebo or vitamin D and, two weeks later, were asked to cycle for 20 minutes again.

The buck needs to stop somewhere

From Vox:

Academic press offices are known to overhype their own research. But the University of Maryland recently took this to appalling new heights — trumpeting an incredibly shoddy study on chocolate milk and concussions that happened to benefit a corporate partner.

Press offices get targeted when this sort of thing happens because they are a necessary link in the chain of hype.  On the other hand, unlike journalists and researchers, their job description doesn’t involve being skeptical about research.

For those who haven’t kept up with the story: the research is looking at chocolate milk produced by a sponsor of the study, compared to other sports drinks. The press release is based on preliminary unpublished data. The drink is fat-free, but contains as much sugar as Coca-Cola. And the press release also says

“There is nothing more important than protecting our student-athletes,” said Clayton Wilcox, superintendent of Washington County Public Schools. “Now that we understand the findings of this study, we are determined to provide Fifth Quarter Fresh to all of our athletes.”

which seems to have got ahead of the evidence rather.

This is exactly the sort of story that’s very unlikely to be the press office’s fault. Either the researchers or someone in management at the university must have decided to put out a press release on preliminary data and to push the product to the local school district. Presumably it was the same people who decided to do a press release on preliminary data from an earlier study in May — data that are still unpublished.

In this example the journalists have done fairly well: Google News shows that coverage of the chocolate milk brand is almost entirely negative.  More generally, though, there’s the problem that academics aren’t always responsible for how their research is spun, and as a result they always have an excuse.

A step in the right direction would be to have all research press releases explicitly endorsed by someone. If that person is a responsible member of the research team, you know who to blame. If it’s just a publicist, well, that tells you something too.

January 17, 2016

Not science yet

I’ve written before about the problem of unpublished science in the news: the news story won’t (can’t) give much detail, and there’s no way to find it out.  Stuff has gone one step further:

Recent animal studies show sleep’s cleansing process in action. But now scientists at Oregon Health & Science University are preparing to conduct a study on humans that would further explain deep sleep’s effect on human brains.

The ‘animal studies’ claim comes without any source. Fortunately the Google comes to the rescue and suggests it’s the research in this story from 2013. Interestingly, a couple of subsequent mouse studies have also found brain problems from interrupted sleep — but since each of the three studies found a different problem, with no overlap, this isn’t as supportive as it sounds.

It would matter less if it weren’t for the first sentence of the story

Forget about needing beauty sleep. It’s your brain that may suffer the most from a lack of deep shut eye.

There’s a definite suggestion that this is a risk factor you can do something about, especially as this is in the “Well & Good” section of the Stuff site.

Even if the Oregon research had been carried out and published, it might well not justify that sort of implication. Research that they’re still preparing to do certainly doesn’t.


[Update: It’s getting to be a trend: the Herald also has a story about research that hasn’t happened yet, on addiction.]

January 1, 2016

As dangerous as bacon?

From the Herald (from the Telegraph)

Using e-cigarettes is no safer than smoking tobacco with nicotine, scientists warned after finding the vapour damages DNA and could cause cancer.

Smoking tobacco is right up near the top of cancer risks that are easy to acquire, both in terms of how big the risk is and in terms of how strong the evidence is.

[There was some stuff here that was right as to the story in the Herald but wrong about the actual research paper, so I got rid of it. Some of the tests in the research paper used real cigarette smoke, and it was worse but not dramatically worse than the e-cig smoke]


The press release is a bit more responsibly written than the story. It describes some of the limitations of the lab tests, and makes it clear that the “no safer than smoking” is an opinion, not a finding. It also gets the journal name right (Oral Oncology) and links to the research paper.

It’s worth quoting the conclusion section from the paper. Here the researchers are writing for other people who understand the issues and whose opinion matters. I’ve deleted one sentence that’s technical stuff basically saying “we saw DNA damage and cell death”

In conclusion, our study strongly suggests that electronic cigarettes are not as safe as their marketing makes them appear to the public. [technical stuff]. Further research is needed to definitively determine the long-term effects of e-cig usage, as well as whether the DNA damage shown in our study as a result of e-cig exposure will lead to mutations that ultimately result in cancer.

That’s very different from the story.