Table 1.
Baseline characteristics of participants based on tertiles of total protein intake
| Variables | All participants | Total protein intake | P-value | ||
|---|---|---|---|---|---|
| Tertile 1 < 28.4 g/day | Tertile 2 28.4–40.8 g/day | Tertile 3 > 40.8 g/day | |||
| Age at baseline (year) [mean ± SD] | 50.6 ± 10.2 | 49.9 ± 11.1 | 50.3 ± 10.3 | 51.5 ± 9.0 | < 0.001* |
| Sex | < 0.001† | ||||
| Women, n (%) | 318,343 (73.3) | 114,048 (78.3) | 106,790(73.7) | 98,232 (67.8) | |
| Men, n (%) | 116,069 (26.7) | 31,483 (21.7) | 38,014 (26.3) | 46,572 (32.2) | |
| Smoking status | < 0.001† | ||||
| Current smoker, n (%) | 92,045 (21.2) | 28,243 (19.5) | 31,573 (21.8) | 32,229 (22.3) | |
| Former smoker, n (%) | 129,547 (29.8) | 45,496 (31.4) | 43,881 (30.3) | 40,170 (27.7) | |
| Never smoker, n (%) | 212,820 (49) | 71,065 (49.1) | 69,350 (47.9) | 72,405 (50.0) | |
| Energy intake, kcal/day | 2160.5 ± 664.4 | 1861.1 ± 542.1 | 2100.5 ± 569.6 | 2481.3 ± 706.3 | < 0.001* |
| Total protein intake, g/day | 38.1 ± 17.4 | 22.5 ± 4.1 | 34.1 ± 3.5 | 57.5 ± 15.7 | < 0.001* |
| Total protein intake, energy % | 16.5 ± 4.1 | 15.0 ± 3.4 | 17.2 ± 3.6 | 17.3 ± 4.8 | < 0.001* |
| Animal-based protein intake, g/day | 24.5 ± 14.1 | 14.9 ± 6.1 | 22.3 ± 8.4 | 36.2 ± 15.9 | < 0.001* |
| Animal-based protein intake, energy % | 10.5 ± 4.1 | 9.8 ± 3.9 | 10.9 ± 3.8 | 10.8 ± 4.2 | < 0.001* |
| Plant-based protein intake, g/day | 13.6 ± 12.2 | 6.8 ± 5.2 | 11.2 ± 7.7 | 21.6 ± 15.7 | < 0.001* |
| Plant-based protein intake, energy % | 5.6 ± 4.5 | 4.6 ± 3.8 | 5.9 ± 4.8 | 6.3 ± 4.5 | < 0.001* |
| Alcohol intake, g/day | 9.4 ± 15.0 | 6.9 ± 11.6 | 8.89 ± 14.46 | 12.3 ± 17.7 | < 0.001* |
Data are presented as mean ± SD for quantitative variables and as number, (%) for qualitative variables
*Based on independent sample t-test
†Based on Chi-2 test
Standard deviation, SD; g, gram; kcal, kilocalorie