TABLE 4.
Risk of total stroke according to RBC fatty acid biomarkers of dairy fat consumption in the NHS (n = 453 cases) and HPFS (n = 122 cases)1
| Cohort-specific fatty acid quartiles |
|||||
| Fatty acid | 1 | 2 | 3 | 4 | P-trend |
| 14:0 | |||||
| NHS | |||||
| Median percentage of total fatty acids | 0.13 | 0.25 | 0.43 | 0.91 | — |
| No. of cases | 89 | 120 | 128 | 116 | — |
| Multivariable HRs (95% CIs) | Reference | 1.52 (0.96, 2.42) | 1.52 (0.92, 2.51) | 1.12 (0.60, 2.10) | 0.68 |
| HPFS | |||||
| Median percentage of total fatty acids | 0.12 | 0.21 | 0.47 | 0.78 | — |
| No. of cases | 24 | 36 | 25 | 37 | — |
| Multivariable HRs (95% CIs) | Reference | 1.52 (0.46, 5.03) | 1.79 (0.44, 7.31) | 4.26 (0.76, 23.88) | 0.09 |
| Pooled | Reference | 1.52 (0.99, 2.34) | 1.55 (0.97, 2.48) | 1.31 (0.73, 2.36) | 0.88 |
| 15:0 | |||||
| NHS | |||||
| Median percentage of total fatty acids | 0.07 | 0.11 | 0.15 | 0.20 | — |
| No. of cases | 136 | 93 | 103 | 121 | — |
| Multivariable HRs (95% CIs) | Reference | 0.58 (0.38, 0.90) | 0.67 (0.43, 1.06) | 0.72 (0.42, 1.23) | 0.24 |
| HPFS | |||||
| Median percentage of total fatty acids | 0.06 | 0.09 | 0.12 | 0.16 | — |
| No. of cases | 29 | 26 | 27 | 40 | — |
| Multivariable HRs (95% CIs) | Reference | 1.24 (0.45, 3.48) | 1.64 (0.53, 5.08) | 3.60 (0.85, 15.23) | 0.08 |
| Pooled | Reference | 0.65 (0.44, 0.97) | 0.76 (0.50, 1.15) | 0.88 (0.53, 1.45) | 0.37 |
| 17:0 | |||||
| NHS | |||||
| Median percentage of total fatty acids | 0.34 | 0.40 | 0.50 | 0.75 | — |
| No. of cases | 136 | 95 | 103 | 119 | — |
| Multivariable HRs (95% CIs) | Reference | 0.74 (0.48, 1.13) | 0.71 (0.45, 1.11) | 0.68 (0.32, 1.45) | 0.33 |
| HPFS | |||||
| Median percentage of total fatty acids | 0.33 | 0.39 | 0.53 | 0.67 | — |
| No. of cases | 34 | 27 | 32 | 29 | — |
| Multivariable HRs (95% CIs) | Reference | 1.02 (0.39, 2.64) | 4.28 (0.88, 20.70) | 5.92 (0.70, 50.04) | 0.10 |
| Pooled | Reference | 0.78 (0.53, 1.15) | 0.81 (0.53, 1.26) | 0.87 (0.42, 1.76) | 0.61 |
| trans 16:1n−7 | |||||
| NHS | |||||
| Median percentage of total fatty acids | 0.11 | 0.15 | 0.18 | 0.25 | — |
| No. of cases | 115 | 109 | 108 | 121 | — |
| Multivariable HRs (95% CIs) | Reference | 0.83 (0.54, 1.26) | 0.88 (0.55, 1.40) | 0.96 (0.52, 1.78) | 0.96 |
| HPFS | |||||
| Median percentage of total fatty acids | 0.10 | 0.12 | 0.15 | 0.20 | — |
| No. of cases | 39 | 20 | 28 | 35 | — |
| Multivariable HRs (95% CIs) | Reference | 0.56 (0.22, 1.39) | 1.17 (0.34, 4.00) | 1.87 (0.45, 7.73) | 0.27 |
| Pooled | Reference | 0.78 (0.53, 1.14) | 0.91 (0.59, 1.41) | 1.07 (0.61, 1.88) | 0.85 |
Multivariable HRs from a conditional logistic model were adjusted for age (y); race (white or nonwhite); month of blood collection; smoking status (never, former, current, or missing); physical activity (metabolic equivalent tasks per week); alcohol (servings/d); family history of diabetes (yes, no, or missing); parental history of myocardial infarction (yes, no, or missing); menopausal status in the NHS (before and after); postmenopausal hormone use in the NHS (no, yes, or missing); consumption of fish (servings/d), processed meats (servings/d), unprocessed meats (servings/d), fruit (servings/d), vegetables (servings/d), whole grains (g/d), coffee (servings/d), sugar-sweetened beverages (servings/d), glycemic load (continuous), dietary calcium (mg/d), polyunsaturated fat (g/d), and total energy (kcal/d); RBC total trans 18:1 (percentage of total fatty acids); RBC total trans 18:2 (percentage of total fatty acids); RBC 16:0 (percentage of total fatty acids); and RBC 18:0 (percentage of total fatty acids). P-trend values within each cohort were computed by assigning the median concentration in each quartile to participants and evaluating this concentration as a continuous variable. Pooled P-trend values were computed by using a generalized least-squares trend analysis (45). HPFS, Health Professionals Follow-Up Study; NHS, Nurses’ Health Study; RBC, red blood cell.