TABLE 8.
Hazard ratios of myocardial infarction and stroke by tertiles of drinking water calcium exposure in 13,207 women with dietary calcium intake below the median (1,016 mg/d)
| HR (95% CI) | ||||
|---|---|---|---|---|
| Tertiles of calcium concentration in tap water (mg/L), range (p50) | Number of participants (cases) | Person-years, n | Age-adjusted model1 | Multivariable adjusted model2 |
| Myocardial infarction | ||||
| 12.3–32 (29.7) | 6464 (512) | 111,675 | 1.00 | 1.00 |
| 32.6–37.7 (37.7) | 4162 (257) | 71,872 | 0.79 (0.68, 0.91) | 0.99 (0.67, 1.45) |
| 41.2–109.8 (70) | 2581 (190) | 43,591 | 0.97 (0.82, 1.15) | 0.93 (0.78, 1.10) |
| Ischemic stroke | ||||
| 12.3–32 (29.7) | 6464 (554) | 111,360 | 1.00 | 1.00 |
| 32.6–37.7 (37.7) | 4162 (323) | 71,544 | 0.91 (0.79, 1.05) | 1.32 (0.95, 1.84) |
| 41.2–109.8 (70) | 2581 (228) | 43,382 | 1.08 (0.93, 1.26) | 1.03 (0.88, 1.22) |
| Hemorrhagic stroke | ||||
| 12.3–32 (29.7) | 6464 (117) | 113,799 | 1.00 | 1.00 |
| 32.6–37.7 (37.7) | 4162 (58) | 72,982 | 0.78 (0.57, 1.08) | 0.66 (0.27, 1.65) |
| 41.2–109.8 (70) | 2581 (34) | 44,481 | 0.76 (0.52, 1.11) | 0.80 (0.53, 1.19) |
Adjusted for age (as time scale).
Adjusted for age (as time scale), level of education (<9, 9, 10–11, 11–12, >12 y), household income (quartiles), smoking status (never, former <10 cigarettes/d, former ≥10 cigarettes/d, current <10 cigarettes/d, current ≥10 cigarettes/d), BMI (<20, 20–24.9, 25–29.9, and 30 kg/cm2), high cholesterol (yes/no), diabetes (yes/no), family history of cardiovascular disease (yes/no), physical activity (walk or bike ≥40 min/wk: yes/no; exercise ≥1 h/wk: yes/no), alcohol intake (never drinker, former drinker, current drinker <3 glasses/wk, current drinker 3–7 glasses/wk, current drinker >7 glasses/wk), and magnesium in drinking water (tertiles).