SERUM HOMOCYSTEINE LEVEL AND PROTEIN-INTAKE ARE RELATED TO RISK OF MICROALBUMINURIA - THE HOORN STUDY

Background. Microalbuminuria (MA) is a strong predictor of cardiovascu lar disease, but its causes are incompletely understood. Hyperhomocyst einemia is a recently recognized risk factor for cardiovascular diseas e independent of established risk factors. It is not known whether hyp erhomocysteinemia is associated with MA, and thus could be a possible cause of microalbuminuria. Methods. We studied an age-, sex- and gluco se-tolerance-stratified random sample of a 50- to 75-year-old general Caucasian population (N = 680). The urinary albumin-to-creatinine rati o (ACR) was measured in an early morning spot urine sample. MA was def ined as an ACR > 3.0 mg/mmol. Results. The prevalence of MA was 4.3% ( 13 of 304) in subjects with normal glucose tolerance, 9.2% (17 of 185) in impaired glucose tolerance and 18.3% (30 of 164) in non-insulin-de pendent diabetes mellitus (NIDDM); it was 3.7% (15 of 402) in subjects without hypertension and 17.9% (45 of 251) in those with hypertension . After adjusting for age, sex, glucose tolerance category, hypertensi on, dyslipidemia and smoking, the odds ratio [OR; 95% confidence inter val (95%CI)] for MA per 5 mu mol/liter total homocysteine increment wa s 1.33 (1.08 to 1.63). Additional adjustment for HbA(1c),, waist-hip r atio, protein intake and serum creatinine did not attenuate the associ ation between MA and total homocysteine. A 0.1 g/kg day increment of p rotein intake was also associated with an increased risk for MA after adjustment for age, sex, classical risk factors and serum total homocy steine [OR (95% CI); 1.20 (1.08 to 1.32)]. Conclusion. Both hyperhomoc ysteinemia and protein intake are related to microalbuminuria independ ent of NIDDM and hypertension. Hyperhomocysteinemia may partly explain the link between MA and increased risk of cardiovascular disease.