ABSTRACT
BACKGROUND: The effects of aging on kidney are anatomic and physiologic abnormality. The most important abnormality is the decreased GFR. Hypertension, diabetes and glomerular disease are the most important risk factors of renal damage. Previous evidence suggested that obesity, smoking and hyperlipidemia progress the renal disease in diabetic nephropathy and glomerular disease. However, it is unclear whether these factors are independently associated with renal insufficiency (GFR<60 mL/min/1.73m2). METHODS: A total of 1, 014 elderly (over 65 years) who participated in health screening examinations in Seoul, Korea was eligible for study. Those who had hypertension, diabetes, urinary abnormality and major disease (cardiovascular disease, cancer, etc) were excluded. Finally, a total of 632 elderly population (age 68.8+/-3.9 yr, M: F=362: 270) was included in the analysis for the present study. Estimated GFR was calculated using the abbreviated MDRD equation. Body mass index (BMI), blood pressure, fasting blood sugar, lipid study, Lp (a), hs CRP and smoking habit were measured. Logistic regression analysis was used to examine the risk factors of renal insufficiency. RESULTS: The mean serum creatinine value was 1.04+/-0.16 mg/dL (male 1.12+/-0.13, female 0.94+/-0.13) and mean estimated GFR was 68.0+/-12.5 mL/min/ 1.73m2 (male 69.7+/-12.5, female 65.8+/-12.0). The prevalence of renal insufficiency was 26%. In renal insufficiency group (n=165), age, BMI, systolic blood pressure, total cholesterol, LDL-cholesterol, Lp (a) and hs CRP were greater than normal renal function group (n=467). After adjusting for potential confounding factor, age (odds ratio=1.12, CI 1.04-1.21, p<0.01), BMI (odds ratio=1.17, CI 1.04-1.31, p=0.01) and smoking in man (odds ratio=4.03, CI 1.04-16.04, p=0.04) were significantly associated with renal insufficiency. CONCLUSION: Mean estimated GFR was 68.0+/-12.5 mL/min/1.73m2 (male 69.7+/-12.5, female 65.8+/-12.0) in elderly population. The prevalence of renal insufficiency was 26%. This study suggests overweight and smoking may be associated with renal insufficiency in the elderly population.