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Comparison of the prevalence of asymptomatic carotid atherosclerosis detected by high-resolution ultrasonography in rural and urban middle-aged Japanese men.

BACKGROUND AND PURPOSE
We have recently shown that extracranial carotid atherosclerosis is not uncommon in urban regions of Japan. Rural data have, however, been scarcely reported. The aim of this study was to investigate the prevalence of asymptomatic extracranial carotid lesions in rural populations compared with urban populations.


METHODS
The subjects in the rural region consisted of 249 men, aged 50 to 69 years. Urban subjects were 610 men of the same age range. Carotid ultrasound examinations were performed with 7.5-MHz high-resolution ultrasonography.


RESULTS
Detection of severe atherosclerosis (stenosis of 50%) was significantly higher (P<.05) in rural subjects (9.6%) than in urban subjects (4.6%). Multiple regression analysis of carotid atherosclerosis showed significant relationships with age, fasting blood glucose, hypertension, pack-years of smoking, total serum cholesterol, and high-density lipoprotein cholesterol for the rural subjects as well as for the urban subjects (P<.05).


CONCLUSION
The present cross-sectional study showed that, in middle-aged men, the prevalence of severe carotid atherosclerosis was higher in rural populations compared with urban populations of Japan. This was attributed to long-term exposure to hypertension.