Table 2. Hazard ratios (95% confidence interval) for cardiovascular mortality endpoints by urine arsenic* concentrations (μg/g creatinine) (N=3,575).
| Quartiles of inorganic plus methylated arsenic species (μg/g creatinine)** | 75th vs. 25th percentile** | p-trend** | ||||
|---|---|---|---|---|---|---|
|
| ||||||
| <5.8 (4.2) | 5.8 - 9.7 (7.5) | 9.8 - 15.7 (12.4) | >15.7 (21.8) | |||
| Cardiovascular Disease Mortality | ||||||
| Cases | 86 | 95 | 115 | 143 | 439 | |
| Person-Years | 13,616 | 13,430 | 12,720 | 12,033 | 51,799 | |
| Model 1 | 1 (Referent) | 1.06 (0.78, 1.43) | 1.21 (0.89, 1.65) | 1.59 (1.17, 2.17) | 1.34 (1.15, 1.56) | <0.001 |
| Model 2 | 1 (Referent) | 1.12 (0.83, 1.52) | 1.26 (0.92, 1.73) | 1.65 (1.20, 2.27) | 1.36 (1.16, 1.58) | <0.001 |
| Model 3 | 1 (Referent) | 1.06 (0.78, 1.44) | 1.24 (0.90, 1.70) | 1.52 (1.10, 2.11) | 1.35 (1.15, 1.58) | <0.001 |
| Model 4 | 1 (Referent) | 1.02 (0.75, 1.39) | 1.15 (0.84, 1.58) | 1.29 (0.93, 1.79) | 1.25 (1.06, 1.47) | 0.007 |
| Coronary Heart Disease Mortality | ||||||
| Cases | 68 | 67 | 87 | 119 | 341 | |
| Person-Years | 13,616 | 13,430 | 12,720 | 12,033 | 51,799 | |
| Model 1 | 1 (Referent) | 0.91 (0.65, 1.30) | 1.11 (0.78, 1.57) | 1.59 (1.13, 2.25) | 1.37 (1.15, 1.63) | <0.001 |
| Model 2 | 1 (Referent) | 0.99 (0.70, 1.41) | 1.18 (0.83, 1.69) | 1.71 (1.19, 2.44) | 1.41 (1.18, 1.68) | <0.001 |
| Model 3 | 1 (Referent) | 0.93 (0.65, 1.32) | 1.15 (0.80, 1.66) | 1.57 (1.08, 2.27) | 1.40 (1.17, 1.68) | <0.001 |
| Model 4 | 1 (Referent) | 0.89 (0.62, 1.27) | 1.06 (0.74, 1.53) | 1.33 (0.92, 1.93) | 1.30 (1.08, 1.57) | 0.005 |
| Stroke Mortality | ||||||
| Cases | 6 | 17 | 13 | 18 | 54 | |
| Person-Years | 13,616 | 13,430 | 12,720 | 12,033 | 51,799 | |
| Model 1 | 1 (Referent) | 1.37 (0.53, 3.55) | 2.46 (0.88, 6.83) | 3.66 (1.34, 10.03) | 1.66 (1.11, 2.48) | 0.014 |
| Model 2 | 1 (Referent) | 1.41 (0.54, 3.67) | 2.16 (0.77, 6.09) | 3.03 (1.08, 8.50) | 1.51 (0.98, 2.32) | 0.061 |
| Model 3 | 1 (Referent) | 1.40 (0.54, 3.65) | 2.05 (0.72, 5.81) | 2.75 (0.97, 7.81) | 1.48 (0.95, 2.32) | 0.082 |
| Model 4 | 1 (Referent) | 1.30 (0.50, 3.39) | 1.97 (0.70, 5.55) | 2.35 (0.83, 6.69) | 1.37 (0.87, 2.14) | 0.175 |
Model 1: Stratified by study center and age-adjusted (age as time metric, age at baseline treated as staggered entries).
Model 2: Further adjusted for sex, education (no, some, or completed high school), smoking status (never, former, current), body mass index (kg/m2), and LDL cholesterol (mg/dL).
Model 3: Further adjusted for hypertension (yes, no), diabetes (yes, no), and estimated glomerular filtration rate (ml/min/1.73m2).
Model 4: Further adjusted for albuminuria (yes, no).
Adjustment for systolic blood pressure and hypertension medication instead of hypertension and hemoglobin A1c levels instead of diabetes resulted in similar results (data not shown).
Sum of inorganic and methylated arsenic (DMA and MMA).
Range (median) of each quartile.
Models comparing the 75th to the 25th percentile (interquartile range) of the sum of inorganic and methylated urine arsenic concentrations (15.7 vs. 5.8 μg/g creatinine). p-trend was obtained from Cox proportional hazards models with log-transformed arsenic as a continuous variable.