Friday, September 23, 2011

Mood Affects Stroke Risk

Observational studies are intriguing concepts.  They give us information linking A to B, but they tell us nothing of whether A causes B or vice versa or perhaps it's just a coincidence.  Luckily, most observational studies give us some clue as to directionality (unlike the chicken & egg conundrum) but it could still be happenstance.

Recently, studies have been published concluding that healthier lifestyles, white-fleshed fruits & vegetables, dark chocolate & high intensity exercise are associated with lower risk of stroke.  I suppose there's always the possibility that some other factor coincident with these factors is the true reason for the decrease in stroke risk.  But somehow I doubt it.  After all, these choices are all reported by healthier people.

But what about our mood?  In a meta-analysis and systematic review published in the Journal of the American Medical Association this week, the authors evaluated 28 prospective studies, including 317,540 cohorts & 8,478 cases of stroke during a 2-29 year follow up, and concluded that depression is associated with an increase risk of total, ischemic & fatal stroke.  Clearly, one could expect to become depressed after suffering a stroke.  However, the participants in these studies were stroke-free at baseline, such that only their moods differentiated one from the other, and thus their risk for stroke later on.

This study of studies builds upon other studies that have arrived at similar conclusions.  In fact, another trial, published last month, came to a similar conclusion after following 80,574 women, stroke-free at baseline, for 6 years in the Nurses' Health Study.

However, the tough part of the job is now set in front of us as we need to figure out the direction of this association.  I say this because one way to prove causation is to treat depression and look for a lower rate of stroke.  Only time will tell as we gather more information.  In the meantime, we should still aggressively treat & manage our depressed patients, not just to remission, but to recovery, so that they can see the rainbow at the end of the tunnel, regardless of whether this affects their stroke risk.