An association between body mass index and estimated glomerular filtration rate

Chronic kidney disease (CKD) is a major public health problem. However, few studies have examined the significance of body mass index (BMI) as a risk factor for the development of CKD in the general Japanese population. Study participants without a clinical history of stroke, transient ischemic attack, myocardial infarction, angina or renal failure (754 men aged 56+/-15 [mean+/-SD] years and 962 women aged 59+/-13 years) were randomly recruited from a single community at the time of their annual health examination. We examined the relationship between increased weight (i.e., BMI) and renal function evaluated by the estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease Study Group equation. Increased BMI was consistently associated with reduced eGFR. Estimated GFR was lower in participants with upper normal body weight (BMI, 22.0 to 24.9 kg/m2) or who were overweight or obese (BMI>or=25 kg/m2), compared with participants with lower normal body weight (BMI, 18.5 to 21.9 kg/m2). Stepwise multiple regression analysis using eGFR as an objective variable, adjusted for various risk factors as explanatory variables, showed that BMI (beta=-0.075) was significantly and independently associated with eGFR, in addition to age, log triglycerides, low-density lipoprotein cholesterol and log fasting blood glucose. Compared with those with lower normal body weight, multivariate-adjusted odds ratios for moderately reduced renal function, defined as an eGFR<60 mL/min/1.73 m2, were 1.86 (1.01-3.42) for upper normal weight and 2.02 (1.01-4.03) for overweight or obese individuals. In conclusion, increased BMI is strongly associated with decreased eGFR in community-dwelling healthy persons.