title: Chronic kidney disease among overweight and obesity with and without metabolic syndrome in an urban Chinese cohort.
abstract: BACKGROUND
  It is widely accepted that metabolic syndrome is associated with an increased risk of chronic kidney disease (CKD). To investigate whether coexisting metabolic syndrome is a necessary condition for CKD in overweight and obese.
  
  
  METHODS
  A cohort study of 6852 Chinese individuals from August 2007 to December 2012. Examinations included a questionnaire, physical measurements, and blood sampling. Hazard ratios for incident CKD were estimated according to combinations of BMI category and absence or presence of metabolic syndrome.
  
  
  RESULTS
  For CKD, multivariable adjusted hazard ratios vs. normal weight individuals without metabolic syndrome were 1.31 (95% CI, 0.89-1.92) in overweight and 2.39 (95% CI, 1.27-4.52) in obese without metabolic syndrome and 1.54 (95% CI, 1.18-3.95) in normal weight, 2.06 (95% CI, 1.27-3.36) in overweight, and 2.77 (95% CI, 1.42-4.31) in obese with metabolic syndrome. There were no interactions between BMI and absence or presence of metabolic syndrome on risk of CKD when BMI was categorized (normal weight, overweight, obese) (P = 0.17). Among individuals both with and without metabolic syndrome there were increasing cumulative incidences of CKD from normal weight through overweight to obese individuals (log-rank trend P = 0.04 to P < 0.001). Although the multivariable adjusted hazard ratio for CKD in individuals with vs. without metabolic syndrome was 1.82 (95% CI, 1.20-2.78) within overweight and obese individuals (log-rank P = 0.005), only 26.1% of the increased risk observed for BMI is explained by metabolic syndrome.
  
  
  CONCLUSIONS
  These findings suggest overweight and obesity are risk factors for CKD regardless of the presence or absence of metabolic syndrome.
authors.affiliation: Department of Health Management, the Third Xiangya Hospital, Central South University, Tongzipo Road 138, 410013, Changsha, Hunan Province, China. 17368895@qq.com.
authors.forename: Xia
authors.initials: X
authors.lastname: Cao
authors.affiliation: Mental Health Institute, the Second Xiangya Hospital, Central South University, Changsha, Hunan Province, China. 25209247@qq.com.
authors.forename: Jiansong
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Clinical Pharmacology Center, the Third Xiangya Hospital, Central South University, Changsha, Hunan Province, China. yuanhongxy@163.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Institute of Aviation Medicine, Beijing, China. 31944468@qq.com.
authors.forename: Liuxin
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Health Management, the Third Xiangya Hospital, Central South University, Tongzipo Road 138, 410013, Changsha, Hunan Province, China. cx_csu@163.com.
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D015994:Incidence; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology*; D050177:Overweight / Q000453:epidemiology; D016016:Proportional Hazards Models; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D012307:Risk Factors; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult