title: Socioeconomic status and reduced kidney function in the Whitehall II Study: role of obesity and metabolic syndrome.
abstract: BACKGROUND
  Previous US-based studies have found that chronic kidney disease (CKD) disproportionately affects those of more adverse social circumstances. Our aim was to show the association between socioeconomic status (SES) and decreased kidney function in a European context and explore the role of obesity and metabolic syndrome. We consider the potential confounding effect of lean muscle mass.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  White participants in the follow-up of the Whitehall II cohort: UK-based European population (age, 55-79 years; n = 5,533), of whom 4,066 men (73%) and 1,467 women (27%) with complete data were analyzed.
  
  
  METHODS
  Self-reported occupational grade/salary range.
  
  
  RESULTS
  Estimated glomerular filtration rate (GFR) using the CKD-EPI (CKD Epidemiology Collaboration) equation.
  
  
  METHODS
  Body mass index (BMI), serum lipid levels, blood pressure, Tanita TBF-300 body composition analyzer, impedance-derived lean mass index (LMI).
  
  
  RESULTS
  Participants in a lower compared with higher occupational grade were at increased odds of having decreased GFR (age- and sex-adjusted OR, 1.31; 95% CI, 1.12-1.53; P = 0.001). Socioeconomic disparity in LMI was evident in women, but not men. After further adjustment for BMI and components of metabolic syndrome, the odds of decreased GFR in whites with a lower compared with higher occupational grade was attenuated by 23.3% (OR, 1.23; 95% CI, 1.06-1.45; P = 0.008). Adjustment for LMI explained 15% of the association between SES and estimated GFR.
  
  
  CONCLUSIONS
  Cross-sectional design, missing data for subset of participants, no urinary data.
  
  
  CONCLUSIONS
  BMI and components of metabolic syndrome may explain up to a quarter of the association between low SES and decreased GFR, suggesting potential modifiable factors.
authors: Department of Epidemiology and Public Health, University College London, London, UK. dr.talqaoud@gmail.com
authors: Talal M
authors: TM
authors: Al-Qaoud
authors: Dorothea
authors: D
authors: Nitsch
authors: Jonathan
authors: J
authors: Wells
authors: Daniel R
authors: DR
authors: Witte
authors: Eric J
authors: EJ
authors: Brunner
mesh_terms: D000288:Administrative Personnel; D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D003430:Cross-Sectional Studies; D050171:Dyslipidemias / Q000453:epidemiology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology*; D008875:Middle Aged; D009765:Obesity; D056128:Obesity, Abdominal / Q000453:epidemiology; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology* / Q000503:physiopathology; D012923:Social Class