Background: In 2004, 7,697 cadmium-exposed persons aged 15 years and older in Mae Sot District, Tak Province, Thailand, were screened for urinary cadmium levels and 554 cases (7.2%) had > or = 5 microg/g creatinine.
Objective: The present study reported the prevalence of renal dysfunction among those with high urinary cadmium (> or = 5 microg/g creatinine).
Material and method: The study persons were interviewed and examined for detection of renal dysfunction. Venous blood and second morning urine were obtained from each subject for microscopic analysis and biochemistry measurements.
Results: Of the 527 examined persons, 14.2% had urinary beta2-microglobulin excretion between 300 and 999 microg/g creatinine, and 19.9% contained > or = 1,000 microg/g creatinine. About 21.1% had serum creatinine concentrations between 1.1 and 1.4 mg/dl and 4.2% contained > or = 1.5 mg/dl. Low glomerular filtration rate (GFR < 60 ml/min/1.73 m2 body surface area) was present in 16.9% of the study persons. Of the persons surveyed, 75.3% had the fractional excretion of phosphate > 5% and 24.7% contained the fractional excretion of potassium > 10%. The overall prevalence rates of hypertension and urinary stones in the study population were 31.3% and 8.9%, respectively. Excretion of urinary beta2-microglobulin significantly increased with increasing urinary cadmium levels. Both increased serum creatinine and decreased GFR appeared to be associated with increasing urinary cadmium although the difference was not statistically significant. There were no significant associations between urinary cadmium levels and excretion of urinary protein, urinary calcium, hypertension, and urinary stones.
Conclusion: Excessive exposure to cadmium might produce renal dysfunction among the present study population. Increased urinary excretion of beta2-microglobulin is a good indicator of renal tubular dysfunction among persons with excessive cadmium exposure.