Effect of Different Obesity Phenotypes on Incidence of Chronic Kidney Disease in Tehranian Adults

Background: The aim of this community-based study is to ascertain the effect of different obesity phenotypes on the incidence of chronic kidney disease in Iranian adults.Study Design: A prospective cohort study, the Tehran Lipid Glucose Study (TLGS).Setting and Participants: Adults aged 20years with a mean age of 40.38years (54.8% female) who were free from chronic kidney disease (CKD) at baseline (phase 1) and were followed up at 3 time stages (phases 2, 3, and 4) for a mean duration of 9.4years to assess the risk for CKD.Predictor: Obesity phenotypes.Outcome: Incidence of chronic kidney disease.Measurements: Glomerular filtration rate (GFR) was estimated from the simplified equation developed using data from the Modification of Diet in Renal Disease (MDRD) Study.Results: CKD events occurred in 1162 participants. The prevalence of the 2 known obesity phenotypes (metabolically obese normal weight [MONW] and metabolically healthy but obese [MHO]) in the overall population was 3.5% and 8.8%, respectively. According to Kaplan-Meier curves, rates of freedom from CKD in the MHO and MONW obesity phenotypes were 75.3% and 60.6%, respectively (p < 0.0001). Age- and sex-adjusted (model 1) hazard ratios for participants with MHO or MONW obesity phenotype were 1.14 (95% confidence interval [CI], 0.91-1.43) and 1.43 (95% CI, 1.09-1.88), respectively. After further adjustment for confounder variables (model 2), multivariate-adjusted hazard ratios for CKD for participants with MHO or MONW obesity phenotypes were 1.23 (95% CI, 0.93-1.62) and 1.43 (95% CI, 1.08-1.90), respectively.Conclusion: Adults with the MONW obesity phenotype compared to those with MHO obesity phenotype have a higher risk for incidence of CKD. The results indicate that having a normal weight is not the only factor to protect against incidence of CKD.