The study aimed at assessing what kinds of factors increase the risk of stroke clarifies the relationship between mental health and stroke, according to the lead investigator and his colleagues.
Paul Surtees, Ph.D., and his colleagues conducted a large population study of more than 20,000 residents of Norfolk taking part in the United Kingdom arm of the 10-country European Prospective Investigation Into Cancer.
They found that lower baseline scores on a mental health inventory (indicating greater distress) were associated with an 11% increased risk of stroke over 8 years of follow-up after adjustment for known stroke risk factors. The association indicated a dose-response relationship.
Having a major depressive episode in the 12 months before the baseline mental-health assessment or at any point in their lives was not significantly associated with a greater stroke risk, however (Neurology 2008;70:788–94).
Dr. Surtees and his colleagues found that of the 20,627 study participants aged 41–80, 5% reported having an episode of major depressive disorder (MDD) in the previous 12 months and 15% reported having such an episode any time during their lives. The mean score on the MHI-5 was 55.2 for those who had experienced an MDD episode in the past 12 months, 76.5 for those who had an MDD episode at any time, and 78.5 for participants who reported never having an MDD episode. The researchers identified 595 strokes in 8.5 years of follow-up, 167 of which were fatal.
For every standard deviation lower score on the MHI-5, overall stroke risk increased by 11%, after adjustment for cardiovascular risk factors.
A single standard deviation lower score on MHI-5 resulted in an adjusted hazard ratio of 1.22 for fatal stroke. A significantly elevated risk of stroke was not found among participants who had experienced an MDD episode in last 12 months or in their lives.