Friday, August 15, 2003

Aspirin, ibuprofen and miscarriage

The British Medical Journal reports today that women using non-steroidal anti-inflammatory drugs and aspirin are 80 percent more likely to suffer miscarriage than those who do not, or who take paracetamol.

The study is based on 1055 pregnant women in the San Francisco area. 162 suffered miscarriage. Of these, 149 had not used aspirin or NSAIDs. 13 had used them. The overall hazard ratio was 1.8, but the 95 percent confidence interval ranged from 1.0 to 3.2. If the 1.0 figure is correct, then we can say there is no effect whatsoever.

Moreover, how many extra miscarriages were there compared to what would have been expected? About 18 percent of non-users suffered miscarriage. If the same rate had been true for NSAID users, then there would have been 9.5 miscarriages. Therefore, the study has found an extra three or four miscarriages for NSAID users. For aspirin, the number of extra miscarriages compared to what would have been expected was... one.

Based on such small numbers, it is hard to see how any firm conclusions can be drawn at all. What is worse, the study was actually investigating the effect of magnetic fields on miscarriage rates. Only after hearing about an admittedly flawed Danish study did the researchers look at the effect of NSAID and aspirin usage. Could this be a case of finding something in the results that is statistically significant but not real?

The strongest conclusion that can be drawn is that more research might be warranted.

Exposure to non-steroidal anti-inflammatory drugs during pregnancy and risk of miscarriage: population based cohort study, British Medical Journal, 16 August 2003

Wednesday, August 13, 2003

The viral hurricane

Just when you thought that New Scientist might be getting all sensible, it comes out with this. Apparently, West Nile Virus is now endemic in the US, and could kill even more people than last year.

How many did it kill in 2002? 282.

Population of the USA? 280million.

Risk? One in a million!

Compare that to road travel, for example. About 3,000 people a year die on Britain's roads. So, the odds of being killed are about one in 20,000. That hasn't stopped me getting into cars. And West Nile Virus is preventable by just the kind of measures you would take in any mosquito-infested area, like slapping on some insect repellent. Mosquitos in the USA at the moment are an irritant, not generally a threat to life.

West Nile Virus set for fresh rampage across US, New Scientist, 8 August 2003

Research deficiencies

New Scientist this week features a contrary article that points out that lack of sun could be linked to internal cancers. Research in the US and UK has shown that lack of sunshine, and hence a lack of the vitamin D produced by exposure to sunshine, could allow cancers to develop more quickly. Vitamin D, it is suggested, is suppresses excessive cell growth.

So, the orthodox sun-causes-cancer are in a tizz about it, because it might dilute the message that was finally getting through to people to cover up in the sun and slap on sun-tan lotion.

The truth is that neither side of the argument has a really convincing case. Either way, the risks would be quite low. The most important thing is to enjoy the sun while it lasts!

Bring me sunshine, New Scientist vol 179 issue 2407 - 09 August 2003, page 30