Urinary Arsenic Species and CKD in a Taiwanese Population: A Case-Control Study
Received 17 December 2008; accepted 5 June 2009. published online 17 August 2009.
Background
Inorganic arsenic has been linked to decreased kidney function through oxidative damage. Arsenic methylation is believed to be a pathway for arsenic metabolism. Lycopene is an antioxidant that reduces oxidative stress; however, the association between urinary arsenic species, plasma lycopene level, and chronic kidney disease (CKD) has seldom been evaluated.
Study Design
Case-control study.
Setting & Participants
125 patients with CKD and 229 controls were recruited from a hospital-based pool.
Predictor
Urinary arsenic species and plasma lycopene level.
Outcomes & Measurements
CKD was defined as estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2, calculated by using the Modification of Diet in Renal Disease Study equation. Plasma lycopene was measured by means of high-performance liquid chromatography. Urinary arsenic species, including arsenite, arsenate, monomethylarsonic acid, and dimethylarsinic acid, were determined by means of high-performance liquid chromatography and hydride generator–atomic absorption spectrometry.
Results
Lycopene level was associated positively with eGFR, and participants with a high serum lycopene level had a significant, inverse association with CKD (odds ratio, 0.41; 95% confidence interval, 0.21 to 0.81). Total arsenic level was associated significantly with CKD in a dose-response relationship, especially in participants with a total arsenic level greater than 20.74 compared with 11.78 μg/g creatinine or less (odds ratio, 4.34; 95% confidence interval, 1.94 to 9.69). Furthermore, participants with a high urinary total arsenic level or participants with a low percentage of dimethylarsinic acid had a positive association with CKD when their plasma lycopene level was low.
Limitations
Because of the single spot evaluation of plasma antioxidants and urinary arsenic species and the small sample size, statistical significance should be interpreted with caution.
Conclusions
This study shows that high urinary total arsenic or low plasma lycopene level is associated positively with CKD. Results suggest that the capacity for arsenic methylation may be associated with CKD in individuals who ingest low arsenic levels in drinking water and also have a low plasma lycopene level.
1Department of Public Health, School of Medicine, Chang Gung Memorial Hospital, and Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
2School of Public Health, Chang Gung Memorial Hospital, and Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
3Department of Chinese Medicine, Chang Gung Memorial Hospital, and Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
4Nephrology Division, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
5Department of Internal Medicine/Nephrology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
6Department of Nuclear Science, National Tsing-Hua University, Hsinchu, Taiwan
7Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan
Address correspondence to Yu-Mei Hsueh, PhD, Department of Public Health, School of Medicine, Taipei Medical University, No. 250 Wu-Hsing St, Taipei 110, Taiwan
ABSTRACT