Friday, December 19, 2003

Once more on DVT and planes

A new report in the Lancet suggests that as many as one percent of long-haul travellers may suffer symptomatic blood clots (deep-vein thrombosis or pulmonary embolism) as a result of sitting still for long periods. The study appears to be quite a good one, with 1000 initial participants monitored. However, the figure seems remarkably high. Are all these people really getting ill just from being on a plane? Of the initial group, nine people were found to have these blood clots. Such a small absolute number means that the figures could be misleading. Moreover, how many of these cases would have resulted in no harm at all if undetected?

What is interesting about the study is the uselessness of preventative measures like aspirin and flight socks, and the fact that two of the nine people causing concern travelled exclusively in business class. Moreover, six of the nine had pre-existing clinical risk factors.

All of which suggests that travelling for long periods on planes contains a very small increased risk of a life-threatening blood clot - but sitting still anywhere for a long period of time would, too, and there's not a great deal you can do about it.

How about faster aircraft?

BBC NEWS | Health | One in 100 get travel blood clots

Tuesday, December 16, 2003

MRSA and antibiotics

An interesting new study suggests that the clampdown on the prescription of antibiotics to treat coughs and colds may have led to an increase in pneumonia deaths. The study, by researchers at the University of Aberdeen, 'found that excess winter deaths rates - those above average levels - from pneumonia went up from 20.4 per 100,000 in 1995-96 to 30.7 per 100,000 in 1999-2000.'

It's only one study, but worth noting nonetheless. Instead of fretting about overuse of antibiotics, perhaps the government could pay someone to clean hospitals properly.

BBC NEWS | Health | UK considers antibiotic policy

George Monbiot on the Wright Brothers: breathtakingly reactionary

According to Monbiot's festering view of history and humanity, we should remember the anniversary as the moment of creation for a weapon of mass destruction (the bomber), an instrument of global domination (tourism), a destroyer of the planet (global warming), and an incidious excuse for government kick-backs (to the aviation industry).

Human freedom, overcoming nature, broadening horizons - all these things become twisted in the misanthropic imagination of Monbiot, who somehow has the reputation for being a radical but would society backwards given half a chance.

Guardian Unlimited | Guardian daily comment | A weapon with wings

How to write the perfect panic

Some hack at the BBC should be warmly congratulated for this piece which encapsulates the perfect moral panic.

1. Assert that undertaking an activity doubles your risk of some terrible outcome.
2. Illustrate just how many people already suffer this terrible outcome.
3. Point out how many people undertake the dangerous activity.
4. Describe in detail just how terrible that outcome can be.


Singularly fail to point out the difference between relative and absolute risk. In other words, note that the risk doubles, but that the risk was tiny to begin with.

To take the particular example.

1. If you drink a lot, you could double your risk of stroke.
2. 130,000 people suffer a stroke in the UK each year.
3. Lots of people drink more than five units in a single session frequently.
4. Having a stroke is fatal in one-third of cases, and can leave the victim with permanent disability.


While stroke is a common form of death, it effects the old disproportionately. According to the Office of National Statistics, ages 0-35 years old suffered 0.2 cases per 1000 population annually in England and Wales from 1994-1998. But those 85 years old and over suffered stroke at a rate of 26.2 per 1000 population i.e. 130 times more often.

BBC NEWS | Health | Stroke warning to binge-drinkers

Prevalence of stroke per 1000 patients, by age, sex and calendar year: 1994 - 98

Monday, December 15, 2003

Drug-rape: an urban myth?

The Roofie Foundation, a group which seeks to highlight the dangers of 'date-rape drugs', has urged the government to launch a Christmas campaign to highlight the dangers of drinks being spiked. According to the group, named after the street-name for rohypnol which has been implicated in drug rape, cases of people being sexually assaulted after consuming drinks spiked with drugs have risen to over 1000 cases in the UK in the past year. Most UK police forces are already running their own campaigns on the subject and drugs like rohypnol and gamma hydroxybutyrate (GHB) have already been restricted with stiff prison sentences for those caught in possession unlawfully. The Roofie Foundation suggests that 'Everyone is aware of their own, personal tolerance to alcohol. If you feel odd, nauseous, slightly drunk, tipsy or wasted after only a couple of drinks, or you know that you cannot be drunk, there is more than a chance that your drink has been spiked. If so get yourself immediately to a place of safety.'

While there have been isolated incidents of such drugs being used, evidence of widespread use is rather thin on the ground. The BBC News report tells us that Essex police found eight spiked drinks among 200 in one club, and that Cumbria police 'received up to seven reports a month from people who believe their drinks may have been spiked'. As for the suggestion that everyone knows their personal tolerance for alcohol, surely painful experience demonstrates that we all get it wrong sometimes? It beggars belief that every time we are unexpectedly inebriated, we should assume we've been slipped a Mickey Finn.

The UK Institute of Biomedical Science noted in December 2000 that, 'Despite a large number of requests for flunitrazepam [rohypnol] analysis, very few positives have been found. Although this could be due partly to the long time delays before the victim has sufficient recall of events to report the incident to the police, it could also indicate that the use of flunitrazepam for this purpose in the UK is not that widespread...There have also been relatively few seizures of flunitrazepam in the UK, and so it is felt that its use in "date rape" is vastly over estimated.'

A study, published in 1999 in the Journal of Analytical Toxicology, examined 1179 samples from across the USA. These were from victims of alleged sexual assault where the assailant was accused of drugging. It was found that in around 40 per cent of cases nothing was found at all, not even alcohol. In the other cases, various substances were found including alcohol (38 per cent), cannabis (18 per cent), cocaine (8 per cent), benzodiazepines (8 per cent), amphetamines (4 per cent), and GHB (4 per cent). In New Zealand in September 2003, a spokesman for the Institute for Environmental Science and Research noted that none of the 162 samples passed on by police over a two-year period in relation to drug rape allegations tested positive for GHB or ketamine.

The truth is that for all the talk of powerful new drugs rendering women senseless and vulnerable, plain old alcohol is by far a more common method to overcome a woman's resistance - hardly a new phenomenon.

Campaign call over spiked drinks, BBC News, 13 December 2003

How to tell, and what to do if you've been spiked, The Roofie Foundation

About the Forensic Science Service, Biomedical Scientist, December 2000

Date rape: drink more common than drugs, Dominion Post, 1 September 2003 (reproduced by NZ Drug Foundation)

(see a later version of this item on spiked)