Obesity and chronic kidney disease (CKD) are major public health problems. In contrary to observations in general population, higher body mass index in those with pre-existing CKD is associated with lower mortality. Chronic Renal Insufficiency Cohort (CRIC) is an ongoing observational study to examine the consequences of CKD with a particular focus on cardiovascular illness like myocardial infarction (heart attack) and stroke. Among CRIC study participants, the investigators propose to obtain visceral and subcutaneous adiposity and physical fitness measures and study its associations with patient-centered outcomes. This study will help the investigators understand the independent and combined effects of visceral adiposity and physical fitness on cardiovascular disease, renal disease progression and death among those with CKD. Further, it will identify mechanisms that could be targeted to reduce the detrimental effects of visceral adiposity in those with kidney disease.