Impact of cadmium, lead and mercury from smoking on renal integrity

Abstract

Background: People are exposed to cadmium (Cd), lead (Pb) and mercury (Hg) from cigarette smoking. It is unknown whether nephrotoxicity is a possible complication or not.

Methods: A total of 68 adult males were included in this study. The studied population was grouped into those who are smokers (n=35), and those who had never smoked (n=33). Cd, Pb and Hg levels were determined in blood, urine, hair and nails to assess the extent of exposure to these metals. Urinary excretion of β2-microglobulin (β2M), N-acetyl-β-D-glucosaminidase (NAG), γ-glutamyltransferase (γ-GT) and alkaline phosphatase (ALP) were determined as markers of tubular damage. Albuminuria was determined as a marker of glomerular damage. Serum levels of creatinine, β2M and blood urea nitrogen (BUN) were determined to assess glomerular filtration.

Results: Blood Cd level and Pb levels in blood and hair were significantly higher in smokers when compared to non-smokers. Blood levels of Cd and Pb correlated significantly with the smoking index (an indicator for the smoking degree) in the smokers group. The studied markers of kidney damage were neither elevated among the smokers, nor correlated with exposure indices of these metals.

Conclusion: Smokers are exposed to Cd and Pb. This exposure is not high enough to produce nephrotoxicity. However, it may incite the nephrotoxicity signs in the presence of risk factors for kidney diseases.