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Showing posts from 2011

Genetic testing and potential harm: DTC or trust me I’m a doctor?

Recently at a couple of conferences (European Human Genetics conference and Consumer Genetics Conf) there have been various speakers questioning DTC genetics and calling for all health related personal genetics to be delivered through medical practitioners. I argued in the past that unregulated tests delivered through practitioners actually have the potential for more harm, not less. By coincidence last week some discrepancies in a DTC and a via MD test were pointed out to me – and they seem topical. Breast feeding has many benefits one of which appears to be increased IQ scores – however not all studies agree, some indicating that results may be confounded by maternal intelligence (see Wikipedia). Sometimes inconsistencies in associating an action with an outcome can be resolved by looking at genetic variation (which tends to increase the error bars when not accounted for). So in 2007 some headlines were made when a study was published by Caspi’s group (PNAS, open access) reporting …

If You Want to Practice Evidence Based Medicine then… Use the Evidence

Travelling on a train to Scotland, all for the first time:

Clinical researcher says: "Look the cows in Scotland are black!".
Physicist replies: "No. Some of the cows in Scotland are black"
Mathematician says:  "No, actually in Scotland there is at least one cow black on one side"
I’ve written about folic acid, homocysteine and various clinical trials of nutrients in the past. I just want to revisit it briefly because I think there are some seriously wrong messages emerging from the conclusions. For an excellent comment on evidence based recommendations see Colby Vorland.

Homocysteine (Hcy) is associated with CVD, may or may not be causal but the evidence is good (Wald et al, BMJ, 2002). Folic acid (Vitamin B9) in reasonable amounts will lower homocysteine  but clinical trials have been carried out, mostly showing not much benefit as far a CVD is concerned. A recent meta-analysis of 8 trials (total 37,485 individuals) seems to confirm this: “Dietary supplemen…

Breast feeding: Personal genetics is in it’s infancy…

There is a lot in the new today about breast feeding – should it be exclusive for at least 6 months (WHO) or should it include some earlier introduction of solid foods (BMJ article)? A lot of the reporting is confusing the issue, claiming or implying that the BMJ authors are saying the 6 months is too long (and pointing out that they have been consultants to the baby food industry). The BMJ authors are not saying that, they simply say that it might be prudent to introduce gradually some solid foods, while still breast feeding before 6 months.There is a useful account at the Marion Nestle blog and I left a comment there which I have expanded upon here. This could be an area where genetic testing can help – blanket advice is never the best for all but confusion (as we have now) is even worse. I blogged about celiac disease and genetic testing a while ago and part of the post addressed exactly the issue of breastfeeding and weaning....babies differ! Probably, very likely, one type of adv…