Friday, April 06, 2007

Smoking, Depression & The Heart

I was intrigued when I read in The Sun that "depression makes people 5 times more likely to have a heart attack". It was reportedly said by a Dr Carmine Pariantes of the Medical Research Council. I thought I'd look into it and just a simple google search revealed that there was a tremendous amount of so-called evidence supporting this statement.

Now I may be simplifying things a bit, but thats me, pretty simple! But I know that it is a psychiatric conundrum that more patients with mental illness and particularly depression smoke than the random population. It is however not known whether the smoking or the depression are the egg or the chicken. It probably is not as simple a relationship as egg laying and chicken sex anyhow!

What is very simple though is the gentle hop, yeah not a jump at all, to the idea that this may be the biggest confounder in any epidemiological endeavour to identify links between smoking and disease. It doesn't take too clever a mind to see that depression with its 5 times link to heart disease could certainly slightly fuck up any study into "passive smoking" and heart disease that was trying to demonstrate a 1.25 times link.

I almost feel like I'm stating the obvious here.

It also makes you think a little about the 2-4 times link between actual smoking and heart disease. Does it not beg the question, did these epidemiologists allow for the 5 times link depression in their groups?

I'm not saying that I've stumbled on the biggest scientific revelation since Archimedes willy bobbed up and down in his bath, but surely this could be a big hole in any study. I notice that one of the authors in the depression and heart disease studies specifically attempted to exclude smoking as a confounder. This was very worthy indeed but how many of the smoking and passive smoking studies have allowed for the confounder of depression?

All I did was put "depression makes people FIVE TIMES more likely to have a heart attack" in Google's search bar. You too could make similar or perhaps more refined enquiries, whilst I take my antidepressants and have a fag or two.