title: Apolipoprotein L1, income and early kidney damage.
abstract: BACKGROUND
  The degree to which genetic or environmental factors are associated with early kidney damage among African Americans (AAs) is unknown.
  
  
  METHODS
  Among 462 AAs in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study, we examined the cross-sectional association between apolipoprotein L1 (APOL1) risk variants and income with: 1) mildly reduced eGFR (<75 mL/min/1.73 m(2), creatinine-cystatin C equation) and 2) elevated urine albumin-to-creatinine ratio (ACR) (≥17 in men and ≥25 mg/g in women). High risk APOL1 status was defined by 2 copies of high-risk variants; low risk if 0 or 1 copy. Income groups were dichotomized as < $14,000/year (lowest income group) or ≥ $14,000/year. Logistic regression models were adjusted for age, sex, and % European ancestry.
  
  
  RESULTS
  Overall, participants' mean age was 47 years and 16% (n = 73) had high risk APOL1 status. Mean eGFR was 99 mL/min/1.73 m(2). Mildly reduced eGFR was prevalent among 11% (n = 51). The lowest income group had higher adjusted odds (aOR) of mildly reduced eGFR than the higher income group (aOR 1.8, 95% CI 1.2-2.7). High-risk APOL1 was not significantly associated with reduced eGFR (aOR 1.5, 95% CI 0.9-2.5). Among 301 participants with ACR data, 7% (n = 21) had elevated ACR. Compared to low-risk, persons with high-risk APOL1 had higher odds of elevated ACR (aOR 3.8, 95% CI 2.0-7.3). Income was not significantly associated with elevated ACR (aOR 1.8, 95% CI 0.7-4.5). There were no significant interactions between APOL1 and income.
  
  
  CONCLUSIONS
  Both genetic and socioeconomic factors may be important determinants of early kidney damage among AAs.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. rtamrat1@jhmi.edu.
authors.forename: Ruth
authors.initials: R
authors.lastname: Tamrat
authors.affiliation: Department of Medicine, University of California, San Francisco, CA, USA. carmenalicia.peralta@ucsf.edu.|San Francisco VA Medical Center, San Francisco, CA, USA. carmenalicia.peralta@ucsf.edu.
authors.forename: Carmen A
authors.initials: CA
authors.lastname: Peralta
authors.affiliation: Laboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA. salman.tajuddin@nih.gov.
authors.forename: Salman M
authors.initials: SM
authors.lastname: Tajuddin
authors.affiliation: Laboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA. evansm@grc.nia.nih.gov.
authors.forename: Michele K
authors.initials: MK
authors.lastname: Evans
authors.affiliation: Laboratory of Epidemiology and Population Sciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA. zondermana@mail.nih.gov.
authors.forename: Alan B
authors.initials: AB
authors.lastname: Zonderman
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA. dcrews1@jhmi.edu.|Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD, USA. dcrews1@jhmi.edu.|Center on Aging and Health, Johns Hopkins Medical Institutions, Baltimore, MD, USA. dcrews1@jhmi.edu.|Division of Nephrology, Johns Hopkins University School of Medicine, Johns Hopkins Bayview Medical Center, 301 Mason F. Lord Drive, Suite 2500, Baltimore, MD, 21224, USA. dcrews1@jhmi.edu.
authors.forename: Deidra C
authors.initials: DC
authors.lastname: Crews
mesh_terms: D001741:Black or African American / Q000235:genetics*; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000235:genetics* / Q000502:physiology; D000419:Albuminuria / Q000235:genetics / Q000503:physiopathology; D016632:Apolipoprotein A-I / Q000235:genetics*; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D004777:Environment; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D015577:Geriatric Assessment / Q000379:methods; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007182:Income; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000208:ethnology* / Q000235:genetics* / Q000503:physiopathology; D018570:Risk Assessment; D012737:Sex Factors; D012959:Socioeconomic Factors
chemical_list: D016632:Apolipoprotein A-I; D003404:Creatinine