Occupational lead exposure and severe CKD: a population-based case-control and prospective observational cohort study in Sweden.
BACKGROUND
The role of low-level lead exposure in the cause of chronic kidney disease (CKD) is unsettled.


METHODS
Case-control study and prospective observational cohort study.


METHODS
926 cases with incident severe CKD (serum creatinine > 3.4 mg/dL for men and > 2.8 mg/dL for women for the first time) and 998 population controls were included. Cases represented nearly all patients with incident severe CKD in Sweden during 2 years. Cases also were followed up prospectively for 7-9 years. Exposed and nonexposed cases were compared with regard to rate of change in estimated glomerular filtration rate (eGFR) and renal survival.


METHODS
Lead exposure was assessed using the expert rating method.


METHODS
Associations between lead exposure and risk of CKD, adjusted for factors associated with this outcome, were analyzed using multivariable logistic regression modeling, whereas links to the rate of change in eGFR were analyzed in mixed-effects multivariable models based on up to 6 measurements. Renal survival in relation to lead exposure was analyzed in a Cox proportional hazards model.


RESULTS
The adjusted OR for incident severe CKD was 0.97 (95% CI, 0.68-1.38) in lead-exposed compared with nonexposed participants. The OR for individuals with the highest average exposure (>0.0075 mg/m(3)) was 1.09 (95% CI, 0.64-1.85). ORs for CKD caused by glomerulonephritis, nephrosclerosis, and diabetic nephropathy did not differ importantly. In patients with CKD ever exposed and most exposed to lead, eGFRs changed by -4.27 and -3.39 mL/min/1.73 m(2)/y compared with -4.55 mL/min/1.73 m(2)/y in nonexposed patients, respectively.


CONCLUSIONS
Only native Swedes were included, which may limit generalizability. Blood lead was not measured to confirm the validity of the expert rating method.


CONCLUSIONS
Our data provide no evidence of an important role of low-level occupational lead exposure in the cause or progression of severe CKD.
Evans
Marie
M
Nephrology Unit, Department of Clinical Sciences Intervention and Technology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden. marie.evans@ki.se
Fored
Carl Michael
CM
Nise
Gun
G
Bellocco
Rino
R
Nyrén
Olof
O
Elinder
Carl-Gustaf
CG
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002908:Chronic Disease; D018450:Disease Progression; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000209:etiology*; D007855:Lead Poisoning / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D011446:Prospective Studies; D012720:Severity of Illness Index; D055815:Young Adult