I’ve blogged before about the association between stroke and depression. It seems logical that people who have strokes are at risk of depression afterwards, but studies have also shown a more concrete relationship between the two conditions.
This new meta-analysis conducted by a research team from Soochow University in China looks at prospective studies to investigate the links between depression and the subsequent risk of stroke.
The authors only searched PubMed and reference lists, but found 17 studies involving over 200,000 patients. They limited their selection to research studies that were:
- Prospective studies looking at a specific population or based in the community
- Depression or depressive symptoms were studied as the exposure
- The incidence of stroke was measured as the outcome
- Participants had no history of stroke at the beginning of the study
- An estimate of the risk of stroke was reported, along with a confidence interval of the depression-stroke association
Here’s what they found:
- Most of the studies (82%) found a positive association between depression and stroke, and this association was statistically significant in around half of the studies (47%)
- People with depression had a significantly increased risk of stroke compared to people without depression (17 studies; RR 1.34, 95% CI 1.17 to 1.54)
- This risk was apparent in both men and women
- Heterogeneity was found in studies (I2=55.1%, p=0.003) when assessed overall, but studies of men alone did not show heterogeneity (p=0.24; I2=23.4%)
- When the authors excluded studies with poor follow-up (<5 years) the association between depression and stroke risk remained (15 studies; RR 1.33, 95% CI 1.16 to 1.53)
- Finally, the authors limited just to studies that used a specific depression assessment scale (CES-D) and found that the association remained with no heterogeneity (eight studies; RR 1.23, 95% CI 1.13 to 1.34; I2=0%, p for heterogeneity=0.86)
The authors concluded:
Depression significantly increased the risk of development of stroke, and this increase was probably independent of other risk factors, including hypertension and diabetes.
Dong JY, Zhang YH, Tong J, et al. Depression and risk of stroke: a meta-analysis of prospective studies. Stroke 2012;43:32–7.