Objective: To compare risk factors for ischemic and hemorrhagic strokes in subjects aged 70 years and above with those in younger subjects.
Design: Case control study, with controls matched for age and sex in 5-year age groups.
Setting: A general district hospital in Hong Kong with a catchment population of over 1 million.
Patients: All patients admitted consecutively over a 6-month period. Classification of stroke was by neurological examination and CT scan, or autopsy if death occurred before CT scanning could be performed.
Exclusion criteria: onset of ictus greater than 48 hours before admission, those with previous stroke, subarachnoid hemorrhage, or embolic stroke from rheumatic heart disease, and those with liver, renal, biliary, or thyroid diseases. For ischemic strokes, 78 pairs less than 70 years and 121 pairs greater than or equal to 70 years were recruited. For hemorrhagic strokes, the numbers were 40 and 39, respectively.
Results: For ischemic strokes, atrial fibrillation and the presence of ischemic heart disease were risk factors only for those aged 70 years and above, while smoking and left ventricular hypertrophy were risk factors only for those below 70 years. Hypertension and glucose intolerance were risk factors for both age groups, although the effect of glucose intolerance was less marked in the older group. No marked difference in serum lipids and lipoproteins as risk factors was observed between the two age groups. Hypertension was the only demonstrable risk factor for hemorrhagic stroke in the younger, but not in the older, group.
Conclusion: Risk factors for ischemic and hemorrhagic strokes are different in elderly compared with younger subjects, with the possibility that certain risk factors for ischemic strokes, in contrast to those for hemorrhagic strokes, may be modifiable even in subjects aged 70 years or above.