Renal function, plasma homocysteine and carotid atherosclerosis in elderlypeople

Although epidemiological studies suggest that people with minor impairment of renal function are at higher risk of stroke and coronary heart disease, the mechanisms underlying this relation are unclear. One explanation may li e with observations that deterioration in renal function is accompanied by elevations in plasma homocysteine concentrations. There is evidence that mo derate hyperhomocysteinemia may play a causal role in atherosclerotic disea se. We investigated the relations between renal function, plasma homocystei ne and atherosclerosis of the carotid arteries in 128 men and women aged 69 -74 years. Renal function was assessed by creatinine clearance and serum cr eatinine. Duplex ultrasonography was used to quantify the degree of stenosi s in the extracranial carotid arteries. Severity of carotid atherosclerosis was greatest in men and women with the poorest renal function, whether mea sured by creatinine clearance or serum creatinine. After adjustment for pla sma homocysteine, pulse pressure and other cardiovascular risk factors, the odds ratio for having carotid stenosis >30% was 4.3 (95% CI 1.4-12.9) in t hose whose creatinine clearance rate was 55 ml/min or less compared with th ose whose creatinine clearance rate was >73 ml/min. Even small decrements i n renal function were associated with increased risk; people whose creatini ne clearance rate was between 56 and 73 ml/min had an odds ratio of 3.8 (95 % CI 1.2-11.9). Plasma homocysteine concentrations were significantly highe r in people with poorer renal function, but they did not explain the associ ations we found between carotid atherosclerosis and creatinine clearance or serum creatinine. (C) 2001 Elsevier Science ireland Ltd. All rights reserv ed.