Characteristics of studies for iAs in drinking water included in the meta-analysis
| Author (reference) | Country (year) | Study design | Mean age (case/control) Percentage of male (case/control) | Sample size (cases) | Definition of cases | Cut-points for arsenic exposure | Adjustment for covariates |
|---|---|---|---|---|---|---|---|
| Lai et al7 | China (1994) | Cross-sectional | – 31.4/44.0 | 891 (86) | Fasting glucose test, 75-g oral glucose tolerance test, a self-reported physician diagnosis, taking insulin or oral hypoglycaemic drugs | Cumulative arsenic exposure (ppm-years) 0 (referent), 0.1–15.0, ≥15.1 (10.05 (1.30 to 77.90)) | Age, sex, BMI, and activity level at work |
| Rahman et al27 | Bangladesh (1998) | Cross-sectional | – 67.4/59.0 | 1014 (43) | Fasting glucose test, 75-g oral glucose tolerance test | Time-weighted arsenic concentration (mg/L) Unexposed (referent), <0.5, 0.5–1.0, >1.0 (8.80 (2.70 to 28.40)) | Age, sex, and BMI |
| Wang et al8 | China (2003) | Cross-sectional | – 46.1/42.9 | 706 334 (35 479) | A self-reported physician diagnosis, taking insulin or oral hypoglycaemic drugs | Nonendemic area (referent), Arseniasis-endemic area (2.69 (2.65 to 2.73)) | Age and sex |
| Islam et al30 | Bangladesh (2012) | Cross-sectional | 47.3/44.6 46.1/30.2 | 1004 (89) | Fasting glucose test, a self-reported physician diagnosis | Cumulative arsenic exposure (µg/L) <22 (referent), 23–32, 33–261, ≥262 (1.90 (1.10 to 3.50)) | Age, sex, education, BMI, and family history of diabetes |
| Jovanovic et al9 | Serbia (2013) | Cohort | – – | 1 519 679 (–) | Fasting glucose test, 75-g oral glucose tolerance test | Water arsenic concentration (µg/L) 0–10.0 (referent) | – |
| Chen et al14 | Bangladesh (2010) | Cross-sectional | 42.0/36.0 49.8/42.8 | 11 319 (241) | A self-reported physician diagnosis, taking insulin or oral hypoglycaemic drugs | Time-weighted arsenic concentration (µg/L) 0.1–8.0 (referent), 8.1–41.0, 41.2–91.7, 91.8–176.1, 176.2–864.0 (1.11 (0.73 to 1.69)) | Age, sex, BMI, smoking status, and educational attainment |
| Tseng et al28 | China (2000) | Cohort | 52.7/46.8 58.5/49.1 | 446 (41) | Fasting glucose test, 75-g oral glucose tolerance test | Cumulative arsenic exposure (mg/L-years) <17 (referent), ≥17 (2.10 (1.10 to 4.20)) | Age, sex, and BMI |
| Li et al11 | China (2013) | Cross-sectional | –– | 669 (42) | Fasting glucose test, a self-reported physician diagnosis, taking insulin or oral hypoglycaemic drugs | Cumulative arsenic exposure (µg/L) <10 (referent), 10–50, >50 (1.58 (0.58 to 4.26)) | Gender, age, alcohol, cigarette, smoking, BMI, consumption, and cumulative arsenic exposure |
| Zierold et al29 | USA (2004) | Cross-sectional | –– | 1185 (–) | A self-reported physician diagnosis | Water arsenic concentration (µg/L) <2 (referent), 2–10, >10 (1.02 (0.49 to 2.15)) | Gender, age, smoking status, and BMI |
| Del Razo et al15 | Mexico (2011) | Cross-sectional | 50.4/32.3 24.0/33.5 | 258 (25) | Fasting glucose test, 75-g oral glucose tolerance test, a self-reported physician diagnosis, taking insulin or oral hypoglycaemic drugs | Cumulative arsenic exposure (ppm-years)– | Age, sex, obesity, and hypertension |
| Makris et al10 | Cyprus (2012) | Cross-sectional | –– | 317 (21) | A self-reported physician diagnosis | Cumulative lifetime arsenic exposure indices (mg) First quintile of arsenic exposure (referent), second vs first, third vs first, fourth vs first, fifth vs first (1.86 (0.30 to 11.59)) | Age, sex, education level, and smoking status |
| James et al31 | USA (2013) | Case-cohort | 56.0/56.0 46.1/46.1 | 629 (141) | Fasting glucose test, 75-g oral glucose tolerance test, a self-reported physician diagnosis | Time-weighted arsenic concentration (µg/L) 1–4.0 (referent), 4.0–8.0, 8.0–20.0, ≥20.0 (1.55 (1.00 to 2.51)) | Ethnicity, age, BMI, and physical activity level |
–, Not available; T2DM, Type 2 diabetes mellitus; BMI, body mass index.