Table 1.
Age and age-adjusted characteristics of total person-time accrued according to score decile for adherence to a low-carbohydrate diet (1st and 10th deciles) in pooled data from three cohorts: the Nurses’ Health Study (1980–2016), the Health Professionals’ Follow-up Study (1986–2016) and the Nurses’ Health Study II (1991–2017).
| Variablea | Overall low-carbohydrate-diet score | Animal-based low-carbohydrate-diet score | Vegetable-based low-carbohydrate-diet score | |||
|---|---|---|---|---|---|---|
| Decile 1 | Decile 10 | Decile 1 | Decile 10 | Decile 1 | Decile 10 | |
| No. of person-years | 341,332 | 343,657 | 343,117 | 338,039 | 342,884 | 346,639 |
| Age, yearsb | 56.6 (11.2) | 55.6 (10.1) | 56.8 (11.3) | 55.8 (10.2) | 56.8 (11.0) | 56.7 (10.6) |
| Low-carbohydrate-diet score | 4.9 (1.9; range: 0–7.4) | 24.8 (1.8; range: 22.5–30.0) | 3.9 (1.9; range: 0–6.5) | 25.6 (1.8; range: 23.1–30.0) | 7.6 (1.9; range: 0–9.7) | 22.4 (1.7; range: 20.5–30.0) |
| Total calories, kcal/day | 1805 (510) | 1698 (498) | 1811 (513) | 1692 (493) | 1789 (490) | 1800 (506) |
| Carbohydrates, % energy | 58.6 (5.5) | 37.2 (5.8) | 58.0 (5.8) | 37.5 (6.1) | 53.6 (6.8) | 43.0 (6.1) |
| Total protein, % energy | 15.6 (2.0) | 21.4 (2.4) | 15.6 (2.1) | 21.6 (2.6) | 18.0 (3.1) | 18.4 (2.6) |
| Animal protein, % energy | 10.1 (2.3) | 17.0 (2.7) | 9.6 (2.2) | 17.4 (2.7) | 13.8 (3.2) | 12.6 (2.9) |
| Vegetable protein, % energy | 5.5 (1.6) | 4.4 (1.0) | 6.0 (1.6) | 4.1 (0.9) | 4.2 (0.9) | 5.8 (1.1) |
| Total fat, % energy | 26.2 (4.4) | 40.0 (5.0) | 27.1 (5.1) | 38.9 (5.4) | 28.4 (5.1) | 37.4 (4.9) |
| Animal fat, % energy | 13.3 (4.7) | 25.9 (7.0) | 12.2 (4.3) | 26.6 (6.6) | 18.6 (5.9) | 18.1 (5.7) |
| Vegetable fat, % energy | 12.9 (3.7) | 14.1 (4.6) | 14.8 (4.4) | 12.3 (3.9) | 9.7 (2.7) | 19.3 (3.8) |
| Saturated fat, % energy | 9.0 (2.3) | 14.4 (2.9) | 8.9 (2.3) | 14.4 (2.9) | 10.8 (2.7) | 12.2 (2.6) |
| Trans fat, % energy | 1.4 (0.6) | 1.8 (0.6) | 1.4 (0.6) | 1.8 (0.5) | 1.4 (0.4) | 1.8 (0.7) |
| Monosaturated fat, % energy | 10.0 (2.0) | 15.8 (2.6) | 10.4 (2.3) | 15.3 (2.7) | 10.7 (2.3) | 15.0 (2.3) |
| Polysaturated fat, % energy | 5.0 (1.1) | 6.4 (1.3) | 5.6 (1.4) | 5.9 (1.2) | 4.5 (0.8) | 7.4 (1.3) |
| Glycaemic indexc | 54.2 (3.1) | 51.3 (3.6) | 53.8 (3.0) | 51.4 (3.5) | 53.4 (3.6) | 52.0 (3.1) |
| Glycaemic loadd | 140.8 (22.2) | 85.4 (18.4) | 139.0 (22.6) | 86.3 (19.0) | 127.2 (24.3) | 99.2 (19.5) |
| Cereal fibre, g/day | 6.7 (3.6) | 4.1 (1.9) | 7.1 (3.7) | 4.0 (1.9) | 5.0 (2.8) | 5.5 (2.4) |
| Fruits, servings/day | 2.8 (1.8) | 1.3 (0.9) | 2.7 (1.8) | 1.3 (0.9) | 2.3 (1.6) | 1.6 (1.0) |
| Vegetables, servings/day | 3.6 (2.0) | 3.1 (1.6) | 3.9 (2.2) | 3.1 (1.5) | 2.9 (1.6) | 3.7 (1.9) |
| Red meat, servings /day | 0.4 (0.3) | 0.9 (0.5) | 0.3 (0.3) | 1.0 (0.5) | 0.6 (0.4) | 0.6 (0.4) |
| Poultry, servings/day | 0.3 (0.2) | 0.4 (0.3) | 0.3 (0.2) | 0.4 (0.3) | 0.3 (0.2) | 0.4 (0.2) |
| Fish, servings/week | 1.4 (1.3) | 1.8 (1.5) | 1.5 (1.3) | 1.7 (1.5) | 1.6 (1.4) | 1.8 (1.4) |
| Nuts, servings/day | 0.3 (0.4) | 0.4 (0.5) | 0.5 (0.5) | 0.3 (0.3) | 0.2 (0.2) | 0.8 (0.8) |
| Legumes, servings/day | 0.5 (0.4) | 0.4 (0.2) | 0.5 (0.4) | 0.4 (0.2) | 0.4 (0.2) | 0.4 (0.3) |
| Eggs, servings/week | 1.4 (1.5) | 2.6 (2.7) | 1.4 (1.4) | 2.7 (2.7) | 1.7 (1.8) | 2.0 (1.9) |
| Caffeine intake, mg/day | 224.8 (199.6) | 313.6 (231.1) | 223.8 (201.6) | 310.6 (229.5) | 228.7 (197.1) | 297.1 (221.9) |
| Alcohol intake, g/day | 4.7 (8.3) | 5.9 (8.2) | 4.3 (7.3) | 7.1 (9.8) | 4.3 (8.3) | 7.5 (9.9) |
| Total nitrate intake, mg/day | 143.5 (84.2) | 142.9 (74.1) | 155.0 (92.1) | 138.9 (71.6) | 119.4 (60.6) | 159.4 (83.2) |
| Family history of glaucoma, % | 7.3 | 7.8 | 7.4 | 7.7 | 7.1 | 8.1 |
| African ancestry, % | 2.3 | 0.9 | 1.9 | 1.0 | 2.6 | 0.5 |
| Self-reported diabetes diagnosis, % | 3.6 | 7.8 | 3.3 | 7.6 | 5.0 | 4.9 |
| Self-reported hypertension diagnosis, % | 31.2 | 37.3 | 29.4 | 38.5 | 35.5 | 31.5 |
| ≥30 pack-years of smoking, % | 9.4 | 17.1 | 8.2 | 17.7 | 12.0 | 14.0 |
| Body mass index (kg/m2) ≥30, % | 7.7 | 21.6 | 7.1 | 21.3 | 12.7 | 13.3 |
| In top 25th percentile for physical activity, % | 30.6 | 19.6 | 32.7 | 19.3 | 24.8 | 26.2 |
HPFS Health Professionals Follow-up Study, NHS Nurses’ Health Study, SD standard deviation.
aValues are presented as means (SD) for continuous variables and percentages for categorical variables.
bAll values other than age have been directly standardized to age distribution (in 5-year age group) of all the participants.
cGlucose was used as the reference for calculations of glycaemic index. The interquartile range was 50.5–54.3 in the NHS, 51.4–54.8 in the HPFS, 51.2–54.7 in the NHS II.
dGlucose was used as the reference for calculations of glycaemic load. The interquartile range was 87.0–109.2 in the NHS, 115.0–143.6 in the HPFS, 109.2–131.3 in the NHS II.