Cadmium-Exposed Population in Mae Sot District, Tak Province: 2. Prevalence of Renal Dysfunction in the Adults
Pisit Limpatanachote MD*, Witaya Swaddiwudhipong MD**, Pranee Mahasakpan BSc, MPH**, Somyot Krintratun MD*
Affiliation : * Department of Internal Medicine, Mae Sot General Hospital, Tak, Thailand ** Department of Community and Social Medicine, Mae Sot General Hospital, Tak, Thailand
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 > 5 μg/g creatinine.
Objective : The present study reported the prevalence of renal dysfunction among those with high urinary
cadmium (> 5 μg/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 β2-microglobulin excretion between 300 and
999 μg/g creatinine, and 19.9% contained > 1,000 μg/g creatinine. About 21.1% had serum creatinine
concentrations between 1.1 and 1.4 mg/dl and 4.2% contained > 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 β2-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 β2-microglobulin is a good indicator of renal tubular dysfunction
among persons with excessive cadmium exposure.
Keywords : Cadmium, Urine, Environmental exposure, Renal dysfunction, Thailand
