Additional Burden of Diseases Associated with Cadmium Exposure: A Case Study of Cadmium Contaminated Rice Fields in Mae Sot District, Tak Province, Thailand

Abstract

The cadmium (Cd) contaminated rice fields in Mae Sot District, Tak Province, Thailand has been one of the major environmental problems in Thailand for the last 10 years. We used disability adjusted life years (DALYs) to estimate the burden of disease attributable to Cd in terms of additional DALYs of Mae Sot residents. Cd exposure data included Cd and β2-microglobulin (β2-MG) in urine (as an internal exposure dose) and estimated cadmium daily intake (as an external exposure dose). Compared to the general Thai population, Mae Sot residents gained 10%-86% DALYs from nephrosis/nephritis, heart diseases, osteoporosis and cancer depending on their Cd exposure type and exposure level. The results for urinary Cd and dietary Cd intake varied according to the studies used for risk estimation. The ceiling effect was observed in results using dietary Cd intake because of the high Cd content in rice grown in the Mae Sot area. The results from β2-MG were more robust with additional DALYs ranging from 36%-86% for heart failure, cerebral infraction, and nephrosis/nephritis. Additional DALYs is a useful approach for assessing the magnitude of environmental Cd exposure. The Mae Sot population lost more healthy life compared to populations living in a non- or less Cd polluted area. This method should be applicable to various types of environmental contamination problems if exposure assessment information is available.

Keywords: DALYs; Mae Sot; cadmium; disability adjusted life years.

Figure 1

Distribution of urinary cadmium (U-Cd) in the surveyed population in Mae Sot areas: residents in Mae Ku (mean = 2.11 µg/g creatinine, 95% CI = 2.04–2.18), Mae Tao (mean = 3.52 µg/g creatinine, 95% CI = 3.41–3.64), and Pra Tad Pha Dang (mean = 2.23 µg/g creatinine, 95% CI = 2.11–2.35).

Figure 2

Distribution of β₂–microglobulin (β₂-MG) in surveyed population in Mae Sot areas: residents in Mae Ku (mean = 150 µg/g creatinine, 95% CI = 108–194), Mae Tao (mean = 264 µg/g creatinine, 95% CI = 199–328), and Pra Tad Pha Dang (mean = 201 µg/g creatinine, 95% CI = 146–257).

Figure 3

Distribution of cadmium (Cd) daily intake in surveyed paddy fields in Mae Sot areas: paddy fields in Mae Ku (mean = 2273 µg/day, 95% CI = 115–4430)), Mae Tao (mean = 3650 µg /day, 95% CI = 2060–5241) and Pra Tad Pha Dang (mean = 3767 µg/day, 95% CI = 736–6799).

Figure 4

Diagram summarizes the process of additional DALYs attributable to cadmium estimation in Mae Sot area.