Serum homocysteine, folate and risk of stroke: Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study.
BACKGROUND
Homocysteine and folate have been suggested to have opposite effects on the risk of stroke, although the results are controversial.


METHODS
The purpose of this study was to assess the effects of serum total homocysteine (tHcy) and serum folate levels on the risk of stroke in a prospective cohort study. The subjects were 1015 men aged 46-64 years and free of prior stroke, examined in 1991-1993 in the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study.


RESULTS
At baseline the mean serum tHcy concentration was 10.9 micromol/l (SD 3.4). During an average follow-up time of 9.6 years, 49 men experienced a stroke, of which 34 were ischaemic. In Cox proportional hazards models, men in the highest tHcy third had a risk factor-adjusted hazard rate ratio (RR) of 2.77 [95% confidence interval (CI): 1.23-6.24] for any stroke and 2.61 (95% CI: 1.02-6.71) for ischaemic stroke, compared with men in the lowest third. The mean baseline serum folate concentration was 10.4 nmol/l (SD 4.1). Men in the highest third of serum folate (>11.2 nmol/l) had an adjusted RR for any stroke of 0.35 (95% CI: 0.14-0.87) and for ischaemic stroke of 0.40 (95% CI: 0.15-1.09), compared with men in the lowest third.


CONCLUSIONS
Elevated serum tHcy is associated with increased risk of all strokes and ischaemic strokes in middle-aged eastern Finnish men free of prior stroke. On the other hand, high serum folate concentration may protect against stroke.
Virtanen
Jyrki K
JK
Research Institute of Public Health, University of Kuopio, Kuopio, Finland. jyrki.virtanen@uku.fi
Voutilainen
Sari
S
Happonen
Pertti
P
Alfthan
Georg
G
Kaikkonen
Jari
J
Mursu
Jaakko
J
Rissanen
Tiina H
TH
Kaplan
George A
GA
Korhonen
Maarit J
MJ
Sivenius
Juhani
J
Salonen
Jukka T
JT
D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005387:Finland / Q000453:epidemiology; D005492:Folic Acid / Q000097:blood*; D005500:Follow-Up Studies; D006397:Hematinics / Q000097:blood*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000453:epidemiology; D016017:Odds Ratio; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000097:blood* / Q000453:epidemiology*; D014280:Triglycerides / Q000097:blood
D015415:Biomarkers; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D006397:Hematinics; D014280:Triglycerides; D006710:Homocysteine; D005492:Folic Acid