Adiposity and ischemic and hemorrhagic stroke: Prospective study in women and meta-analysis.
OBJECTIVE
To compare associations of body mass index (BMI) with ischemic stroke and hemorrhagic stroke risk, and to review the worldwide evidence.


METHODS
We recruited 1.3 million previously stroke-free UK women between 1996 and 2001 (mean age 57 years [SD 5]) and followed them by record linkage for hospital admissions and deaths. We used Cox regression to estimate adjusted relative risks for ischemic and hemorrhagic (intracerebral or subarachnoid hemorrhage) stroke in relation to BMI. We conducted a meta-analysis of published findings from prospective studies on these associations.


RESULTS
During an average follow-up of 11.7 years, there were 20,549 first strokes, of which 9,993 were specified as ischemic and 5,852 as hemorrhagic. Increased BMI was associated with an increased risk of ischemic stroke (relative risk 1.21 per 5 kg/m2BMI, 95% confidence interval 1.18-1.23, p < 0.0001) but a decreased risk of hemorrhagic stroke (relative risk 0.89 per 5 kg/m2BMI, 0.86-0.92, p < 0.0001). The BMI-associated trends for ischemic and hemorrhagic stroke were significantly different (heterogeneity: p < 0.0001) but were not significantly different for intracerebral hemorrhage (n = 2,790) and subarachnoid hemorrhage (n = 3,062) (heterogeneity: p = 0.5). Published data from prospective studies showed consistently greater BMI-associated relative risks for ischemic than hemorrhagic stroke with most evidence (prior to this study) coming from Asian populations.


CONCLUSIONS
In UK women, higher BMI is associated with increased risk of ischemic stroke but decreased risk of hemorrhagic stroke. The totality of the available published evidence suggests that BMI-associated risks are greater for ischemic than for hemorrhagic stroke.
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Mary E
ME
Kroll
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Jane
J
Green
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Valerie
V
Beral
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Cathie L M
CL
Sudlow
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Anna
A
Brown
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Oksana
O
Kirichek
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
Alison
A
Price
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK.
TienYu Owen
TO
Yang
From the Nuffield Department of Population Health (M.E.K., J.G., V.B., A.B., O.K., A.P., T.O.Y., G.K.R.), University of Oxford; and Centre for Clinical Brain Sciences (C.L.M.S.), University of Edinburgh, UK. gill.reeves@ceu.ox.ac.uk.
Gillian K
GK
Reeves
D050154:Adiposity; D015992:Body Mass Index; D002545:Brain Ischemia / Q000453:epidemiology* / Q000503:physiopathology; D002543:Cerebral Hemorrhage / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D020521:Stroke / Q000453:epidemiology* / Q000503:physiopathology; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology