TABLE 2.
Relative risks and 95% CIs of stroke by quintile of percentage energy from protein among participants in the Health Professionals Follow-Up Study, 1986–2004 (n = 43,960)1
| Quintile 1 | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 | P for linear trend | |
| Total protein | ||||||
| Median (% of energy) | 14.6 | 16.7 | 18.2 | 19.8 | 22.5 | |
| Total stroke (no. of cases) | 223 | 201 | 208 | 186 | 239 | |
| Model 1 | 1.00 (referent) | 0.93 (0.76, 1.13) | 0.97 (0.80, 1.18) | 0.81 (0.66, 0.99) | 1.02 (0.84, 1.24) | 0.86 |
| Model 2 | 1.00 (referent) | 1.02 (0.83, 1.24) | 1.12 (0.91, 1.38) | 0.97 (0.77, 1.20) | 1.25 (0.99, 1.57) | 0.09 |
| Model 3 | 1.00 (referent) | 1.01 (0.83, 1.24) | 1.08 (0.88, 1.33) | 0.92 (0.74, 1.14) | 1.14 (0.90, 1.43) | 0.43 |
| Ischemic stroke (no. of cases) | 134 | 126 | 123 | 111 | 144 | |
| Model 1 | 1.00 (referent) | 0.94 (0.73, 1.21) | 0.93 (0.72, 1.19) | 0.77 (0.60, 1.00) | 0.97 (0.75, 1.24) | 0.52 |
| Model 2 | 1.00 (referent) | 1.04 (0.80, 1.34) | 1.10 (0.84, 1.43) | 0.94 (0.71, 1.25) | 1.24 (0.92, 1.66) | 0.25 |
| Model 3 | 1.00 (referent) | 1.02 (0.79, 1.32) | 1.07 (0.82, 1.40) | 0.90 (0.67, 1.19) | 1.13 (0.84, 1.52) | 0.61 |
| Hemorrhagic stroke (no. of cases) | 37 | 37 | 33 | 29 | 35 | |
| Model 1 | 1.00 (referent) | 1.59 (0.90, 2.79) | 1.34 (0.75, 2.40) | 1.22 (0.67, 2.20) | 1.12 (0.60, 2.08) | 0.93 |
| Model 2 | 1.00 (referent) | 1.84 (1.01, 3.33) | 1.59 (0.85, 2.97) | 1.53 (0.79, 2.96) | 1.36 (0.66, 2.81) | 0.64 |
| Model 3 | 1.00 (referent) | 1.85 (1.02, 3.36) | 1.56 (0.83, 2.91) | 1 47 (0.76, 2.85) | 1.24 (0.59, 2.58) | 0.85 |
| Animal protein2 | ||||||
| Median (% of energy) | 9.3 | 11.5 | 13.1 | 14.8 | 17.7 | |
| Total stroke (no. of cases) | 204 | 208 | 204 | 207 | 234 | |
| Model 1 | 1.00 (referent) | 1.05 (0.86, 1.28) | 0.99 (0.81, 1.22) | 0.99 (0.80, 1.21) | 1.01 (0.82, 1.24) | 0.88 |
| Model 2 | 1.00 (referent) | 1.11 (0.90, 1.36) | 1.11 (0.89, 1.37) | 1.13 (0.91, 1.41) | 1.22 (0.96, 1.55) | 0.13 |
| Model 3 | 1.00 (referent) | 1.10 (0.89, 1.34) | 1.08 (0.87, 1.33) | 1.06 (0.85, 1.32) | 1.11 (0.87, 1.41) | 0.52 |
| Ischemic stroke (no. of cases) | 127 | 118 | 126 | 126 | 141 | |
| Model 1 | 1.00 (referent) | 0.92 (0.71, 1.19) | 0.92 (0.71, 1.19) | 0.91 (0.70, 1.18) | 0.90 (0.68, 1.17) | 0.46 |
| Model 2 | 1.00 (referent) | 0.97 (0.74, 1.26) | 1.04 (0.79, 1.36) | 1.06 (0.80, 1.41) | 1.12 (0.82, 1.52) | 0.39 |
| Model 3 | 1.00 (referent) | 0.95 (0.73, 1.24) | 1.02 (0.78, 1.33) | 1.00 (0.75, 1.32) | 1.03 (0.75, 1.40) | 0.80 |
| Hemorrhagic stroke (no. of cases) | 33 | 42 | 31 | 32 | 33 | |
| Model 1 | 1.00 (referent) | 1.58 (0.90, 2.77) | 1.00 (0.54, 1.84) | 1.18 (0.64, 2.16) | 1.13 (0.60, 2.13) | 0.90 |
| Model 2 | 1.00 (referent) | 1.83 (1.02, 3.28) | 1.23 (0.64, 2.34) | 1.54 (0.79, 2.97) | 1.41 (0.67, 2.94) | 0.58 |
| Model 3 | 1.00 (referent) | 1.83 (1.02, 3.29) | 1.19 (0.62, 2.27) | 1.45 (0.75, 2.82) | 1.26 (0.60, 2.65) | 0.83 |
| Vegetable protein3 | ||||||
| Median (% of energy) | 3.7 | 4.4 | 4.9 | 5.5 | 6.5 | |
| Total stroke (no. of cases) | 245 | 218 | 203 | 202 | 189 | |
| Model 1 | 1.00 (referent) | 0.92 (0.76, 1.12) | 0.84 (0.69, 1.03) | 0.79 (0.65, 0.98) | 0.72 (0.57, 0.90) | 0.002 |
| Model 2 | 1.00 (referent) | 1.02 (0.82, 1.25) | 0.97 (0.76, 1.23) | 0.93 (0.71, 1.21) | 0.84 (0.61, 1.14) | 0.21 |
| Model 3 | 1.00 (referent) | 1.02 (0.83, 1.26) | 0.98 (0.78, 1.25) | 0.93 (0.72, 1.21) | 0.82 (0.60, 1.12) | 0.17 |
| Ischemic stroke (no. of cases) | 157 | 128 | 113 | 131 | 109 | |
| Model 1 | 1.00 (referent) | 0.86 (0.67, 1.10) | 0.74 (0.57, 0.96) | 0.82 (0.63, 1.06) | 0.64 (0.48, 0.86) | 0.005 |
| Model 2 | 1.00 (referent) | 0.93 (0.71, 1.21) | 0.84 (0.62, 1.14) | 0.96 (0.69, 1.34) | 0.79 (0.53, 1.19) | 0.33 |
| Model 3 | 1.00 (referent) | 0.94 (0.72, 1.22) | 0.86 (0.63, 1.18) | 0.98 (0.70, 1.36) | 0.80 (0.53, 1.19) | 0.33 |
| Hemorrhagic stroke (no. of cases) | 32 | 36 | 43 | 28 | 32 | |
| Model 1 | 1.00 (referent) | 1.05 (0.59, 1.87) | 1.30 (0.74, 2.30) | 1.02 (0.55, 1.91) | 1.06 (0.53, 2.09) | 0.92 |
| Model 2 | 1.00 (referent) | 1.12 (0.59, 2.13) | 1.42 (0.70, 2.86) | 1.13 (0.51, 2.51) | 1.16 (0.46, 2.95) | 0.85 |
| Model 3 | 1.00 (referent) | 1.15 (0.61, 2.18) | 1.46 (0.72, 2.95) | 1.14 (0.52, 2.54) | 1.16 (0.46, 2.95) | 0.87 |
Relative risks (95% CIs) were calculated with the use of Cox proportional hazards regression models. Model 1 was adjusted for age and quintiles of percentage of energy from saturated fat, monounsaturated fat, polyunsaturated fat, and trans fat and quintiles of calories. Model 2 was the same as Model 1 with additional adjustments for quintiles of fiber, folate, vitamin B-6, vitamin B-12, potassium, vitamin C, magnesium, total omega-3 fatty acids, glycemic index and physical activity, family history of myocardial infarction (yes, no), BMI (in kg/m2; <23, 23–24.9, 25–28.9, ≥29), cigarette smoking (never smoked cigarettes; nonsmoker with unknown past history; past smoker; current smoker of 1–14, 15–24, ≥25 cigarettes/d; current but unknown no. of cigarettes/d), and alcohol (0, 0.1–4.9, 5–14.9, ≥15 g/d) and multivitamin use (yes, no). Model 3 was the same as Model 2 with additional adjustments for baseline (1986) status of hypertension, hypercholesterolemia, and diabetes.
Additionally adjusted for quintiles of percentage of energy from vegetable protein.
Additionally adjusted for quintiles of percentage of energy from animal protein.