Obesity is associated with family history of ESRD in incident dialysis patients

Background Obesity is an established risk factor for chronic kidney disease and aggregates in families. The objective of this study is to examine the relationship between obesity and family history of end-stage renal disease (ESRD). Methods: Data were collected from 25,883 incident patients with ESRD in US ESRD Network 6 (Georgia, North Carolina, and South Carolina) dialysis clinics between 1995 and 2003. Family history is defined as a first- or second-degree relative with ESRD. Body mass index (BMI) at dialysis therapy initiation was classified as underweight (BMI < 18.5 kg/m(2)), normal (BMI, 18.5 to <25 kg/m(2)), overweight (BMI, 25 to < 30 kg/m(2)), obese (BMI, 30 to <35 kg/m(2)), or morbidly obese (BMI >= 35 kg/m(2)). Results Twenty-three percent of patients reported a family history of ESRD. Of patients reporting a family history of ESRD, 5.5% were underweight, 32.5% had normal BMI, 28.0% were overweight, 17.3% were obese, and 16.7% were morbidly obese. After controlling for age, race, sex, primary cause of ESRD, history of diabetes, history of hypertension, and estimated glomerular filtration rate at dialysis therapy initiation, reported family history of ESRD was associated with being overweight (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.08 to 1.26), obese (OR, 1.25; 95% Cl, 1.14 to 1.37), and morbidly obese (OR, 1.40; 95% Cl, 1.27 to 1.55). Conclusion: Obesity at dialysis therapy initiation was associated independently with reported family history of ESRD. This finding suggests that behavioral factors, adiposity-related genes, and gene-by-BMI interaction may contribute to familial risk for ESRD. This finding also suggests that management of obesity may be even more important for patients with a family history of ESRD than for the general population.