TABLE 9.
Hazard ratios of myocardial infarction and stroke by tertiles of drinking water calcium exposure in 13,207 women with dietary calcium intake above 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) | 6645 (534) | 113,162 | 1.00 | 1.00 |
| 32.6–37.7 (37.7) | 4132 (300) | 70,011 | 0.88 (0.76, 1.01) | 1.05 (0.72, 1.53) |
| 41.2–109.8 (70) | 2430 (192) | 40,400 | 1.05 (0.89, 1.24) | 0.95 (0.80, 1.13) |
| Ischemic stroke | ||||
| 12.3–32 (29.7) | 6645 (648) | 112,651 | 1.00 | 1.00 |
| 32.6–37.7 (37.7) | 4132 (295) | 70,023 | 0.69 (0.60, 0.79) | 1.01 (0.72, 1.43) |
| 41.2–109.8 (70) | 2430 (197) | 40,653 | 0.88 (0.75, 1.03) | 0.86 (0.73, 1.02) |
| Hemorrhagic stroke | ||||
| 12.3–32 (29.7) | 6645 (129) | 115,506 | 1.00 | 1.00 |
| 32.6–37.7 (37.7) | 4132 (63) | 71,298 | 0.77 (0.57, 1.04) | 1.42 (0.71, 2.81) |
| 41.2–109.8 (70) | 2430 (41) | 41,441 | 0.92 (0.65, 1.30) | 0.90 (0.63, 1.30) |
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).