Associations of blood lead with estimated glomerular filtration rate using MDRD, CKD-EPI and serum cystatin C-based equations.
BACKGROUND
Low-level lead exposure is widespread and has been implicated as a chronic kidney disease (CKD) risk factor. However, studies evaluating associations of lead dose with newer, potentially more accurate, estimates of kidney function, in participants with a wide range of glomerular filtration rates (GFRs), are scarce.


METHODS
We compared associations of blood lead and estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and cystatin C single variable, multivariable and combined creatinine/cystatin C equations in 3941 adults who participated in the 1999-2002 National Health and Nutrition Examination Survey cystatin C subsample.


RESULTS
Geometric mean blood lead was 1.7 μg/dL. After multivariable adjustment, differences [95% confidence interval (CI)] in mean eGFR for a doubling of blood lead were -1.9 (-3.2, -0.7), -1.7 (-3.0, -0.5) and -1.4 (-2.3, -0.5) mL/min/1.73 m(2), using the cystatin C single variable, multivariable and combined creatinine/cystatin C equations, respectively, reflecting lower eGFR with increased blood lead. The corresponding differences (95% CI) were -0.9 (-1.9, 0.02) and -0.9 (-1.8, 0.01) using the creatinine-based MDRD and CKD-EPI equations, respectively. In participants aged ≥60 years, differences in mean eGFR ranged from -3.0 to -4.5 mL/min/1.73 m(2), and odds of reduced eGFR (<60 mL/min/1.73 m(2)) were increased for all estimates of GFR.


CONCLUSIONS
These results support the inclusion of cystatin C-based eGFR in future lead research and provide additional evidence for environmental lead exposure as a CKD risk factor.
Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
June T
JT
Spector
Ana
A
Navas-Acien
Jeffrey
J
Fadrowski
Eliseo
E
Guallar
Bernard
B
Jaar
Virginia M
VM
Weaver
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002648:Child; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood; D004032:Diet; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000175:diagnosis*; D007677:Kidney Function Tests; D007854:Lead / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012307:Risk Factors; D055815:Young Adult
D055316:Cystatin C; D007854:Lead; D003404:Creatinine
Clin Chem. 2007 Apr;53(4):766-72
17332152
Environ Health Perspect. 1998 Aug;106 Suppl 4:961-7
9703479
Pediatr Nephrol. 2003 Oct;18(10):981-5
12920638
Environ Res. 2008 Sep;108(1):15-20
18514186
Am J Epidemiol. 2009 Nov 1;170(9):1156-64
19700501
Ann Intern Med. 2009 May 5;150(9):604-12
19414839
Am J Kidney Dis. 2008 Mar;51(3):395-406
18295055
Am J Kidney Dis. 2007 Dec;50(6):918-26
18037092
Kidney Int. 2009 Mar;75(6):652-60
19119287
Am J Physiol Heart Circ Physiol. 2008 Aug;295(2):H454-65
18567711
Environ Health Perspect. 2005 Nov;113(11):1627-31
16263522
Kidney Int. 2006 Dec;70(12):2074-84
17063179
Kidney Int. 2009 Mar;75(6):578-80
19247381
JAMA. 2007 Nov 7;298(17):2038-47
17986697
Am J Kidney Dis. 2008 Mar;51(3):385-94
18295054
Scand J Clin Lab Invest. 2004;64(1):25-30
15025426
Epidemiology. 2003 Nov;14(6):719-27
14569189
J Am Soc Nephrol. 2004 Apr;15(4):1016-22
15034104
Nephrol Dial Transplant. 2008 Jan;23(1):154-60
17911090
Nicotine Tob Res. 2005 Aug;7(4):557-64
16085527
Arch Intern Med. 2010 Jan 11;170(1):75-82
20065202
Ann Intern Med. 1999 Mar 16;130(6):461-70
10075613
Kidney Int. 1992 May;41(5):1192-203
1614034
Am J Med. 2006 Aug;119(8):707.e1-9
16887418
Curr Opin Nephrol Hypertens. 2006 Nov;15(6):610-6
17053476
Clin Nephrol. 2006 Aug;66(2):89-97
16939064
Clin Biochem. 2007 Mar;40(5-6):383-91
17316593
Lancet. 2001 May 26;357(9269):1660-9
11425371
Environ Res. 2006 Sep;102(1):9-12
16782088
Arch Intern Med. 2005 Oct 10;165(18):2155-61
16217007
Sci Total Environ. 2006 Jun 15;363(1-3):95-106
16181659
Nephron. 1976;16(1):31-41
1244564
JAMA. 1996 Apr 17;275(15):1177-81
8609685
Arch Environ Health. 1993 Jul-Aug;48(4):271-8
8357279
Am J Kidney Dis. 2002 Aug;40(2):221-6
12148093
Kidney Int. 2006 Jun;69(11):2049-56
16641918
Environ Health Perspect. 2004 Aug;112(11):1178-82
15289163
Environ Health Perspect. 2006 Apr;114(4):584-90
16581550
N Engl J Med. 2003 Jan 23;348(4):277-86
12540640