Table 1.
Age-standardized characteristics of study participants in Nurses’ Health Study (1984–2014), Nurses’ Health Study II (1991–2017), and Health Professionals Follow-up Study (1986–2016)
| Total whole grain consumption | |||||
|---|---|---|---|---|---|
| Q1 | Q2 | Q3 | Q4 | Q5 | |
| Nurses’ Health Study | |||||
| No of participants | 15,033 | 14,567 | 14,858 | 14,925 | 14,861 |
| Total whole grain, servings/day | 0.1 (0.1, 0.2) | 0.4 (0.3, 0.4) | 0.7 (0.6, 0.7) | 1 (0.9, 1.2) | 1.9 (1.6, 2.4) |
| Total whole grain, g/day | 2.3 (1.3, 3.3) | 6.1 (5.2, 7) | 10.4 (9.2, 11.7) | 16.7 (14.8, 18.8) | 29.9 (24.9, 38.8) |
| Age (years) | 49.8 (6.9) | 49.9 (7.1) | 50.3 (7.1) | 51.2 (7.2) | 52.5 (7.2) |
| Baseline body mass index (kg/m2) | 25.2 (5) | 25.3 (5) | 25.2 (4.7) | 24.9 (4.6) | 24.4 (4.3) |
| Race | |||||
| White, % | 96.8 | 97.8 | 98.1 | 98.1 | 98.2 |
| African American, % | 0.3 | 0.2 | 0.2 | 0.2 | 0.3 |
| Asian, % | 1.2 | 0.7 | 0.6 | 0.5 | 0.4 |
| Others, % | 1.7 | 1.2 | 1.1 | 1.2 | 1.1 |
| Physical activity (MET-h/week)a | 5.1 (1.9, 15.2) | 6.8 (2.4, 16.5) | 7.7 (2.9, 18.5) | 8.4 (3.1, 20.2) | 9.9 (3.4, 21.5) |
| Hypertension, % | 9.2 | 8.4 | 7.7 | 7.2 | 6.8 |
| High cholesterol, % | 3.0 | 3.0 | 3.2 | 3.6 | 4.1 |
| Baseline diabetes, % | 0.9 | 0.8 | 0.8 | 0.9 | 1.0 |
| Family history of MI, % | 19.9 | 19.9 | 19.6 | 18.4 | 19.4 |
| Current smokers, % | 36.2 | 27.6 | 23.3 | 19.1 | 14.5 |
| Multivitamin use, % | 30.3 | 34.1 | 36.8 | 39.8 | 44.3 |
| Oral contraceptive use, % | 46.7 | 48.7 | 49.6 | 49.7 | 49.9 |
| Hormone use | |||||
| premenopausal, % | 52.1 | 52.5 | 53.2 | 52.6 | 52.4 |
| postmenopausal-never, % | 27.4 | 25.8 | 24.6 | 23.7 | 22.8 |
| postmenopausal-current, % | 9.1 | 10.9 | 11.1 | 12.4 | 13.7 |
| postmenopausal-past, % | 11.4 | 10.8 | 11.0 | 11.4 | 11.2 |
| Alcohol consumption (g/day)a | 2.8 (0, 12.5) | 2.7 (0, 10.8) | 2.6 (0, 9.5) | 2 (0, 7.8) | 1.8 (0, 5.8) |
| Total energy intake (kcal/day) | 1710.5 (553) | 1790.1 (541.4) | 1781.9 (540.7) | 1775.5 (523) | 1651.4 (475.5) |
| Modified alternative healthy eating index | 43.4 (9.9) | 44.8 (9.7) | 46.3 (9.8) | 47.5 (10) | 50 (10.6) |
| Nurses’ Health Study II | |||||
| No of participants | 18,384 | 18,203 | 18,280 | 18,345 | 18,218 |
| Total whole grain, servings/day | 0.3 (0.2, 0.4) | 0.7 (0.6, 0.8) | 1.1 (1, 1.2) | 1.6 (1.4, 1.7) | 2.5 (2.2, 3.1) |
| Total whole grain, g/day | 4.9 (3.1, 6.5) | 10.9 (9.5, 12.3) | 17 (15.4, 18.7) | 24.8 (22.5, 27.5) | 40.1 (34.6, 49.3) |
| Age (years) | 36.6 (4.7) | 36.5 (4.7) | 36.5 (4.7) | 36.5 (4.6) | 36.9 (4.6) |
| Baseline body mass index (kg/m2) | 25.1 (5.9) | 25 (5.6) | 24.7 (5.3) | 24.4 (5) | 23.9 (4.6) |
| Race | |||||
| White, % | 94.3 | 96.2 | 97.1 | 97.5 | 97.3 |
| African American, % | 0.5 | 0.6 | 0.4 | 0.4 | 0.6 |
| Asian, % | 3.1 | 1.4 | 1.1 | 0.9 | 1.0 |
| Others, % | 2.1 | 1.8 | 1.3 | 1.1 | 1.1 |
| Physical activity (MET-h/week)a | 9.4 (3.4, 22) | 11.3 (4.5, 24.6) | 12.6 (5.2, 25.9) | 13.9 (5.9, 28.4) | 16.5 (7.3, 33) |
| Hypertension, % | 4.4 | 3.8 | 3.2 | 3.0 | 2.6 |
| High cholesterol, % | 10.1 | 9.8 | 9.4 | 9.1 | 9.0 |
| Baseline diabetes, % | 0.7 | 0.6 | 0.6 | 0.5 | 0.8 |
| Family history of MI, % | 49.6 | 49.7 | 48.8 | 48.4 | 48.2 |
| Current smokers, % | 19.6 | 14.5 | 11.4 | 8.6 | 7.2 |
| Multivitamin use, % | 36.1 | 40.7 | 44.1 | 47.7 | 50.7 |
| Oral contraceptive use, % | 82.5 | 84.6 | 84.7 | 84.4 | 83.3 |
| Hormone use | |||||
| premenopausal, % | 97.1 | 96.8 | 97.1 | 97.0 | 96.7 |
| postmenopausal-never, % | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 |
| postmenopausal-current, % | 2.4 | 2.8 | 2.4 | 2.6 | 2.8 |
| postmenopausal-past, % | 0.3 | 0.3 | 0.2 | 0.2 | 0.3 |
| Alcohol consumption (g/day)a | 0.9 (0, 3) | 0.9 (0, 3.7) | 0.9 (0, 3.7) | 0.9 (0, 3.5) | 0.9 (0, 3) |
| Total energy intake (kcal/day) | 1771.7 (578) | 1821.1 (561.2) | 1823.9 (550.8) | 1820 (526.8) | 1709.8 (509.6) |
| Modified alternative healthy eating index | 44.7 (10) | 44.8 (9.9) | 45.1 (10) | 45.3 (9.9) | 45.9 (10.2) |
| Health Professionals Follow-up Study | |||||
| No of participants | 7948 | 7892 | 7818 | 7892 | 7905 |
| Total whole grain, servings/day | 0.2 (0.1, 0.3) | 0.6 (0.5, 0.7) | 1.1 (0.9, 1.2) | 1.7 (1.5, 1.9) | 2.8 (2.4, 3.6) |
| Total whole grain, g/day | 3.4 (1.6, 5.1) | 9.9 (8.3, 11.6) | 16.9 (15, 19) | 26.6 (23.7, 29.9) | 45.5 (38.8, 57.6) |
| Age (years) | 52.5 (9.2) | 52 (9.3) | 52.4 (9.3) | 53 (9.5) | 53.8 (9.5) |
| Baseline body mass index (kg/m2) | 25.8 (3.3) | 25.8 (3.3) | 25.6 (3.3) | 25.4 (3.3) | 24.8 (3) |
| Race | |||||
| White, % | 92.9 | 94.9 | 95.9 | 96.8 | 95.4 |
| African American, % | 2.3 | 2.3 | 2.1 | 1.8 | 2.4 |
| Asian, % | 3.6 | 1.4 | 1.0 | 0.9 | 1.3 |
| Others, % | 1.1 | 1.4 | 0.9 | 0.5 | 0.9 |
| Physical activity (MET-h/week)a | 8.5 (2.5, 23.1) | 10.9 (3.5, 26.3) | 12.3 (4.4, 27.7) | 13.9 (4.8, 29.4) | 16.7 (6.3, 35.1) |
| Hypertension, % | 22.2 | 20.8 | 18.3 | 18.0 | 18.5 |
| High cholesterol, % | 9.2 | 9.5 | 10.0 | 10.3 | 12.8 |
| Baseline diabetes, % | 2.1 | 2.1 | 2.3 | 2.4 | 2.9 |
| Family history of MI, % | 12.4 | 12.3 | 11.9 | 11.5 | 11.9 |
| Current smokers, % | 17.7 | 12.5 | 8.6 | 6.2 | 4.5 |
| Multivitamin use, % | 34.7 | 37.8 | 41.2 | 45.1 | 50.3 |
| Alcohol consumption (g/day)a | 6.9 (1, 18.8) | 6.6 (1.1, 16.5) | 6.4 (1, 16.1) | 5.5 (0.9, 13.7) | 3.9 (0, 12) |
| Total energy intake (Kcal/day) | 1986.9 (646.9) | 2036 (642.9) | 2062.9 (637.6) | 2021 (595.9) | 1880.5 (556.3) |
| Modified alternative healthy eating index | 45.9 (10.6) | 48.5 (10.3) | 49.9 (10.4) | 51.5 (10.5) | 54.7 (10.3) |
Values are means (SD) or percentages and are standardized to the age distribution of the study population
aValue is median (interquartile range)