study of the relationship between body composition, insulin resistance and hdl levels

Conditions: Obesity; Insulin Resistance

Summary: approximately 20 million people in the united states have some form of kidney failure. people with kidney failure have an increased chance of having low levels of high density lipid (hdl), so called "good cholesterol." patients who are overweight or obese also have low levels of hdl. the investigators are trying to find out whether causes of low hdl are the same in people who are overweight and in patients with kidney failure so that in the future doctors can better treat low hdl cholesterol levels. people with low levels of hdl are more likely to have heart attacks and strokes and are more likely to lose kidney function. this study hope to learn more about how kidney failure causes low hdl cholesterol levels.

this study is not a treatment or outcome trial.this is a single center cross sectional analysis of body composition and lipoprotein level and structure among patients with graded levels of renal failure in comparison to control subjects. to study the relationship between hdl cholesterol and both body composition and insulin resistance measured as homeostatic model assessment (homa) among a cohort of non diabetic non-proteinuric patients with advanced chronic kidney disease (ckd) compared to non diabetic subjects having normal kidney function. renal patients chosen will be with advanced ckd stage 3, stage 4, and stage 5 - which is end stage renal failure (esrd) and on hemodialysis. fasting blood will be taken for the evaluation of baseline lipid and renal function, and blood glucose level to make sure that there is no recent evidence of diabetes. body compositions will be measured with 2 established methods: dexa and whole body bio-impedance spectroscopy (bis). fat mass and analysis will be estimated so as to provide a relationship between adiposity, insulin resistance, residual renal function and hdl levels and structure.

Eligibility criteria:
inclusion criteria: * self report of stable body weight during the past six months; * bmi 18-40 kg/m2; hemodialysis dependent for at least 3 months, prevalent esrd (end stage renal disease) cohort; * gfr \> 15 \< 44 ml/min (ckd cohort); * gfr \> 60 ml/min (control cohort). exclusion criteria: * diabetes mellitus (american diabetes association definition: fasting glucose \>120 mg/dl); * evidence of liver disorder, ie; hepatitis * evidence of thyroid disorders * hiv by medical history (hiv test will not be performed) * renal transplant recipient * oral contraceptive/ hormone replacement therapy * systemic use of systemic or inhaled corticosteroids in the past month * contraindication to systemic anticoagulation (heparin administration is necessary to measure levels of lpl, hl); * hemoglobin \< 8.5 g/dl (anemia); * current, within 2 months use of any hypolipidemic or anti-diabetic agents; * patients treated with a fibric acid derivative or niacin in the past 4 weeks; * urinary protein excretion of greater than 0.5 grams per day; * any other condition that, in the opinion of the investigators, would put the subject at risk.

Keywords: high density lipoprotein (hdl) lipid insulin resistance glomerular filtration rate (gfr) obesity