Xu H, et al. – In this study, researchers determined whether genetic confounding or obesity-associated diabetes mediates the association between body mass index (BMI) and chronic kidney disease (CKD) via examining 29,136 Swedish twins with no history of CKD or diabetes by first using traditional Cox regression in a cohort design and then controlling for shared genetic factors within twin pairs. They identified 1,113 incident cases CKD and 2,282 diabetes cases during an average follow-up of 12.8 years. They observed higher incidence rates of both CKD and diabetes among heavier twins than their leaner siblings, particularly when BMI differed by > 2 kg/m². Irrespective of genetic confounding, increased CKD risk was noted in correlation with a higher BMI. Hence, maintenance of a normal BMI may prevent a large proportion of CKD cases in a population.