Posts filed under Research (111)

April 4, 2014

Thomas Lumley’s latest Listener column

…”One of the problems in developing drugs is detecting serious side effects. People who need medication tend to be unwell, so it’s hard to find a reliable comparison. That’s why the roughly threefold increase in heart-attack risk among Vioxx users took so long to be detected …”

Read his column, Faulty Powers, here.

March 26, 2014

Are web-based student drinking interventions worthwhile?

Heavy drinking and the societal harm it causes is a big issue and attracts a lot of media and scholarly attention (and Statschat’s, too). So we were interested to see today’s new release from the Journal of the American Medical Association. It describes a double-blind, parallel-group, individually-randomised trial that studied moderate to heavy student drinkers from seven of our eight universities to see if a web-based alcohol screening and intervention programme reduced their unhealthy drinking behaviour.

And the short answer? Not really. But if they identified as Māori, the answer was … yes, with a caveat. More on that in a moment.

Statistician Nicholas Horton and colleagues used an online questionnaire to identify students at Otago, Auckland, Canterbury, Victoria, Lincoln, Massey, and Waikato who had unhealthy drinking habits. Half the students were assigned at random to receive personalised feedback and the other students had no input. Five months later, researchers followed up with the students on certain aspects of their drinking.

The overall result? “The intervention group tended to have less drinking and fewer problems then the control group, but the effects were relatively modest,” says Professor Horton. The take-away message: A web-based alcohol screening and intervention program had little effect on unhealthy drinking among New Zealand uni students. Restrictions on alcohol availability and promotion are still needed if we really want to tackle alcohol abuse.

But among Māori students, who comprise 10% of our national uni population, those receiving intervention were found to drink 22% less alcohol and to experience 19% fewer alcohol-related academic problems at the five-month follow-up. The paper suggests that Māori students are possibly more heavily influenced by social-norm feedback than non-Māori students. “Māori students may have a stronger group identity, enhanced by being a small minority in the university setting.” But the paper warns that the difference could also be due to chance, “underscoring the need to undertake replication and further studies evaluating web-based alcohol screening and brief intervention in full-scale effectiveness trials.”

The paper is here. Read the JAMA editorial here.

 

 

 

March 25, 2014

An ounce of diagnosis

The Disease Prevention Illusion: a tragedy in five parts, by Hilda Bastian

“An ounce of prevention is worth a pound of cure.” We’ve recognized the false expectations we inflate with the fast and loose use of the word “cure” and usually speak of “treatment” instead. We need to be just as careful with the P-word.

 

March 18, 2014

Seven sigma?

The cosmologists are excited today, and there is data visualisation all over my Twitter feed

That’s a nice display of uncertainty at different levels of evidence, before (red) and after (blue) adding new data.  To get some idea of what is greater than zero and why they care, read the post by our upstairs neighbour Richard Easther (head of the Physics department)

March 16, 2014

The only way he knows how

Q: Did you see the story about aphrodisiacs on Stuff this weekend?

A: Yes

Q: How did they find out which ones worked?

A: It says “Richard Cornish investigates the only way he knows how.”

Q: Randomised n-of-1 trials with independent evaluation by someone who doesn’t know what he’s eaten?

A: Sadly, no.

Q: Allocating different foods, and some control foods, to a large group of people and collecting their reports?

A: No

Q: Getting a librarian to help him review the scientific research on the topic? Or the traditional knowledge?

A: Not really, though there are some biochemical or historical anecdotes for many of the items.

Q: Um. Did he just try each food as you would if you wanted to use it as an aphrodisiac?

A: Not that, either.

Q: I give up. What did he do?

A: ” It was my task to consume them in a bland environment, with no chance of any stimulation or excitement.”

Q: What a waste. But aren’t you being a bit harsh?  He’s a food writer and TV producer. He does sustainability and Spanish food. He’s not a science journalist or an investigative reporter.  They didn’t expect anyone to take it seriously.

A: Ok, but some of the nutrition stories and sex stories they run are supposed to be taken seriously. It should be easier to tell which is which online.

Q: Wait, isn’t it March now?

A: Yes.

Q: That sounds more like a Valentine’s Day column

A: An interesting point. You thought of that faster than I did.

Q: Well?

A: It is a Valentine’s Day column. From the Southland Times. Except they took out the foie gras and truffles to make it suitable for the national audience. Reruns aren’t just for The Simpsons, you know.

March 4, 2014

What you do know that ain’t so

From a randomised trial of four different sets of information about vaccine benefits (via Brendan Nyhan)

Parents were randomly assigned to receive 1 of 4 interventions: (1) information explaining the lack of evidence that MMR causes autism from the Centers for Disease Control and Prevention; (2) textual information about the dangers of the diseases prevented by MMR from the Vaccine Information Statement; (3) images of children who have diseases prevented by the MMR vaccine; (4) a dramatic narrative about an infant who almost died of measles from a Centers for Disease Control and Prevention fact sheet; or to a control group.

In particular, intervention 4 is a popular and sensible idea, and it has occurred to people from Benjamin Franklin to Kiwi parents and the Herald. However:

RESULTS: None of the interventions increased parental intent to vaccinate a future child. Refuting claims of an MMR/autism link successfully reduced misperceptions that vaccines cause autism but nonetheless decreased intent to vaccinate among parents who had the least favorable vaccine attitudes. In addition, images of sick children increased expressed belief in a vaccine/autism link and a dramatic narrative about an infant in danger increased self-reported belief in serious vaccine side effects.

This research is depressing from the point of view of science communication. The problem is that the message goes in two apparently opposite ways.  One conclusion is that increasing trust in science and medicine is the only solution, which would require more public contact and communication, and openness about uncertainty.  The other conclusion is that a public health advertising campaign is a treatment, and like any other treatment it should be evaluated for safety and effectiveness before it’s applied to the population, an approach that seems to imply a reduction in open and unfiltered communication.

I don’t think the contradiction is unavoidable; I think more communication about research process — who are we and what do we actually do — will help, but also that advertising, whether government-funded or pushed by PR departments, is actually dangerous.  If we overstate claims about the biochemical effects of compounds in chocolate, or the number of deaths prevented by lowering the blood alcohol limit, why should we be trusted on important issues?

 

February 26, 2014

Caricatures in music space

There’s a map going around Twitter, being described as the most popular band in each US state


It’s a bit surprising that every state has a different favourite band, so I looked at the site listed on the map as the source.  In fact, the listed bands are not the most popular ones in any of the states. They are something more interesting.

Paul Lamere used Spotify (and perhaps other social music-streaming services) to get music listening preferences for 200000 people. He then looked at which artist in the top 100 for a state had the worst ranking over the US as a whole. He forced the result to be different for every state by bumping the less-populous state to its next choice when there was a tie. So, as the title on the map actually says, these are the most distinctive bands for a state, not the most popular.  They are caricatures, not photographs.

Since he had data based on postal code (ZIP code), it’s a pity he grouped these all the way up to the state level.  It would have been interesting to see urban vs suburban vs rural differences, and the major geographical trends across states such as Texas.

February 17, 2014

Two charts about animal use in research

Prompted by Siouxsie Wiles’s report of talking to an anti-vivisectionist demonstrator, here are two charts from the annual report of the National Animal Ethics Advisory Committee. These are the people who monitor the use of animals in research, testing, and teaching in New Zealand.

The first chart shows what types of animals are used and what happens to them afterwards

animal-bar

More than half are sheep and cattle, mostly cattle, and mostly subjected to things like breeding or eating different types of feed.  There are quite a lot of mice used in biological research, though the numbers are decreasing (down 24% last year) partly because they are being replaced by zebrafish. None are monkeys.

About half of the research is commercial, with about a quarter at universities

animal-pie

Some people will still be opposed to livestock research because they’re opposed to livestock farming. Some people still  disapprove of the use of mice in biomedical research. But anyone who wants to campaign on those issues should be clear that those are the issues.

February 14, 2014

Interpreted with caution

There’s a new paper in The Lancet, summarising population-based surveys across the world that asked about non-partner sexual violence. The paper’s conclusion, from the abstract

Sexual violence against women is common worldwide, with endemic levels seen in some areas, although large variations between settings need to be interpreted with caution because of differences in data availability and levels of disclosure.

The story in Stuff has the headline Sexual assaults more than double world average, and starts

The rate of sexual assault in Australia and New Zealand is more than double the world average, according to a new report.

After several highly publicised rapes and murders of young women in India and South Africa, researchers from several countries  decided to review and estimate prevalence of sexual violence against women in 56 countries.

The results, published in the UK medical journal The Lancet, found that 7.2 per cent of women aged 15 years or older  reported being sexually assaulted by someone other than an intimate  partner at least once in their lives.

The study found that Australia and New Zealand has the third-highest rate, more than double the world average, with 16.4  per cent.

If you look at the raw numbers reported in the paper, they showed Australia/NZ at about ten times the rate of the Caribbean or southern Latin America or Eastern Europe, which is really not plausible. Statistical adjustment for differing types of survey reduced that margin, but as the researchers explicitly and carefully point out, a lot of the variation between regions could easily be due to variations in disclosure, and it suggests that rape is being underestimated in some areas.

As usual with extreme international comparisons, the headline is both probably wrong and missing the real point. The real point is that roughly one in six women in Australia & NZ report having experienced sexual violence.

February 13, 2014

Commuting costs are housing costs

There’s an interesting story in the Herald about research on the combined cost of commuting and housing in Auckland.

“If you just look at housing costs alone, outlying areas appear really affordable and it initially seems to make sense to say, hey, let’s open up greenfield sites on the urban periphery and develop here,” Mr Mattingly said. “But when you include these broader costs, they are not as affordable as they seem.”

This is the sort of conclusion I like to see, as a non-driver, so I looked at the research paper (there wasn’t a link, but the Herald did give the researchers’ names and journal name). I was disappointed that the impact of commuting costs wasn’t higher, at least until you got out to Pukekohe or Warkworth.

Since the journal is published by a company known for its dedication to preventing knowledge being disseminated for free, I won’t show any whole maps, but here are the central chunks of the cost maps with and without commuting costs. Or perhaps the other way around.