日系米人非糖尿病者における虚血性心疾患発症予知因子としての尿中微量アルブミンの臨床的意義

Abstract

Urinary microalbumin (UMA) is recognized as a marker of renal complications in IDDM and is associated with increased mortality in NIDDM. We investigated the association of UMA with cardiovascular risk factors in 380 non-diabetic Japanese-Americans. Among 380 of these subjects, 24 (6.3%) were found to have elevated UMA (30-260μg/ml) at the baseline. The subjects with elevated UMA had significantly higher systolic and diastolic blood pressure (BP), triglycerides (TG) and total cholesterol (CH) than those without UMA. Among 355 normoalbuminuric subjects, a 3-year follow-up study indicated that 316 remained at normal levels (NN group) while 39 (11.0%, NM group) developed UMA or proteinuria (260μg/ml∼). Compared to normoalbuminuric subjects, subjects who developed UMA or proteinuria had significantly higher levels of systolic BP, TG, serum glucose, total immunoreactive insulin (ΣIRI) levels during 75g OGTT, and ischemic ECG abnormalities but lower HDL-CH levels at baseline. Only 4.2% of the subjects without hypertriglyceridemia, hyperinsulinemia, high BP and glucose intolerance developed UMA during the 3-year follow-up period. The incidence of UMA was found to increase in accordance with the number of these factors present, reaching 50% in subjects having all four factors.To confirm whether UMA is a new potent marker of cardiovascular risk, we investigated the clinical data of these 355 normoalbuminuric subjects for a 6-year period preceding the baseline. The subjects who developed UMA were found to have higher serum glucose, BP, TG and insulin levels but lower HDL-CH levels than those who remained normoalbuminuric, even in the 6-year period before the baseline.UMA, which is associated with hypertriglyceridemia, hyperinsulinemia, high BP and glucose intolerance, may thus be a potent marker of increased cardiovascular risk in non-diabetic Japanese-Americans.