Table 4.

Ecological studies of arsenic and kidney disease mortality

Reference and Country	Population	Study Design	N	Outcome Ascertainment	Arsenic Assessment	Exposure Levels	SMR (95 % CI)	Adjustment Factors
High arsenic levels in drinking water (> 100 μg/L)
Tsai et al. 1999 Putai, Taiwan	4 townships (BFD endemic) in two counties to local population of both counties	Ecological	206 male deaths, 196 female deaths	Nephritis, nephrotic syndrome, nephrosis mortality validated by death certificate using ICD-9 code	Groundwater data from Chen et al. 1962	Historical content of wells ranged from 0.25 to 1.14 ppm (median 0.78 ppm) (Chen et al. 1962)	1.10 (1.00–1.22) endemic area vs. local reference	Age
Chiu et al. 2005 Putai, Taiwan	4 townships (BFD endemic) Use age-specific and sex-specific mortality rate of entire Taiwan population to standardize SMR	Ecological	273 male deaths 248 female deaths (1971–2000)	Nephritis, nephrosis, nephrotic syndrome mortality validated by death certificate using ICD-9 code	Groundwater data from Chen et al. 1962	Historical well water median of 0.78 ppm Current supply < 0.01 ppm (Chen et al. 1962)	1.05 (0.96–1.14)	Age
Smith et al. 2012 Northern Chile	SMR of Antofagasta region of Chile was standardized by the mortality rate from all of Chile except Region II. Age : 30–49 years	Ecological	14 male, 14 female deaths (born 1940–1957); 6 male, 6 female deaths (born 1958–1970)	Chronic renal disease mortality validated by the Ministry of Health using ICD-9 codes	Groundwater measured previously in Smith et al. 1998	Historical mean water arsenic in Antofagasta 870 μg/L Rest of Chile: < 10 μg/L (mean of 14 μg/L in 1984)	2.03 (1.48–2.76)	Age
Low to moderate arsenic levels in drinking water (< 100 μg/L)
Lewis et al. 1999 Utah, United States	Several small towns in Millard County, Utah	Ecological	27 male deaths, 14 female deaths	Nephritis, nephrosis, nephrotic syndrome mortality validated by death certificate using ICD-9 code	Historical data from Utah State Health Laboratory	Historical (1970s) data suggested a mean of 150 ppb with a range of 53 to 750 ppb. Paper stipulates that this is of individuals with < 200 ppb exposure	1.50 (1.11–2.04)	Age
Meliker et al. 2007 Michigan, United States	Comparison of six county area of Michigan vs. rest of Michigan	Ecological	614 male deaths 679 female deaths	Kidney disease mortality validated by Vital Records and Health Data Development Section of MDCH using ICD9 code.	Groundwater (MDEQ database)	Population weighted median in rest of Michigan: 1.27 μg/L Study area: 7.58 μg/L	1.33 (1.26–1.41)	Age