Background and purpose: Higher plasma total homocysteine (tHcy) levels have been associated with carotid atherosclerosis and cerebral infarction in whites. However, data regarding such associations are limited for Asians. This study examined associations between tHcy levels and severity of carotid atherosclerosis in Japanese subjects. Additionally, because lacunar infarction is the most prevalent type of ischemic stroke in Japan, we also investigated its associations with tHcy levels.
Methods: The subjects were 152 Japanese patients (age, 66.2+/-11.0 years) at our hospital. Using ultrasound, we evaluated severity of carotid atherosclerosis by plaque score, which is defined by the sum of all plaque (intima-media thickness > or =1.1 mm) height in bilateral carotid arteries. In 112 of 152 patients, the existence of lacunar infarction was evaluated on brain MRI scans.
Results: A moderate linear association was found between tHcy levels and plaque score (r=0.48, P<0.0001). Moreover, tHcy level was associated with plaque score (beta=0.26, P<0.001) independently of traditional atherosclerotic risk factors. In logistic regression analyses, each 1-micromol/L-higher tHcy level was associated with a 1.37-fold-higher [95% confidence interval (CI), 1.19 to 1.58] likelihood for lacunar infarction, increasing the likelihood by 1.22-fold (95% CI, 1.04 to 1.43) independently of traditional atherosclerotic risk factors.
Conclusions: Higher tHcy levels appear to have associations with increased severity of carotid atherosclerotic plaques and prevalent lacunar infarction in the Japanese. Larger prospective studies are necessary to establish whether higher tHcy levels serve as a harbinger for insidious carotid and cerebrovascular diseases.