Table 2.
Descriptive characteristics of the study population stratified by serum 25(OH)D3 level
| Characteristic | Serum 25(OH)D3, ng/mL | P for trend | ||||
|---|---|---|---|---|---|---|
| Total | <10 | 10–20 | 20–30 | ≥30 | ||
| N | 4139 | 111 | 1539 | 1895 | 594 | |
| Sex | 0.000 | |||||
| Male, n (%) | 1451 (35.1) | 24 (21.6) | 412 (26.8) | 707 (37.3) | 308 (51.9) | |
| Female, n (%) | 2688 (64.9) | 87 (78.4) | 11275 (73.2) | 1188 (62.7) | 286 (48.1) | |
| Age, years | 67.9 ± 6.7 | 71.3 ± 8.1a | 69.1 ± 7.1b | 67.0 ± 6.2c | 66.8 ± 6.2c | 0.000 |
| Body mass index, kg/m2 | 24.82 ± 3.31 | 24.14 ± 3.47 | 24.75 ± 3.48 | 24.97 ± 3.22 | 24.66 ± 3.09 | 0.083 |
| Education level | 0.005 | |||||
| Illiterate, n (%) | 118 (2.9) | 12 (10.8) | 53 (3.4) | 43 (2.3) | 10 (1.7) | |
| Elementary school, n (%) | 502 (12.1) | 24 (21.6) | 215 (14.0) | 205 (10.8) | 58 (9.8) | |
| Junior high school, n (%) | 1950 (47.1) | 39 (35.1) | 680 (44.2) | 929 (49.0) | 302 (50.8) | |
| Senior high school, n (%) | 880 (21.3) | 23 (20.7) | 321 (20.9) | 410 (21.6) | 126 (21.2) | |
| College, n (%) | 689 (16.6) | 13 (11.7) | 270 (17.5) | 308 (16.3) | 98 (16.5) | |
| Physical activity | 0.000 | |||||
| Inactive, n (%) | 919 (22.2) | 39 (35.1) | 388 (25.2) | 391 (20.6) | 101 (17.0) | |
| Moderate, n (%) | 296 (7.2) | 5 (4.5) | 110 (7.1) | 143 (7.5) | 38 (6.4) | |
| Active, n (%) | 2924 (70.6) | 67 (60.4) | 1041 (67.6) | 1361 (71.8) | 455 (76.6) | |
| Smoking status, n (%) | 0.000 | |||||
| Yes, n (%) | 556 (13.4) | 19 (17.1) | 216 (14.0) | 248 (13.1) | 73 (12.3) | |
| No, n (%) | 3583 (86.6) | 92 (82.9) | 1323 (86.0) | 1647 (86.9) | 521 (87.7) | |
| Timed up and go test, s | 9.14 ± 3.29 | 11.56 ± 7.62a | 9.52 ± 3.99b | 8.83 ± 2.35c | 8.67 ± 2.02c | 0.000 |
| Handgrip strength, kg | 22.52 ± 8.80 | 19.35 ± 7.41a | 20.80 ± 8.07a | 23.16 ± 8.98b | 25.50 ± 9.13c | 0.000 |
| Calf circumference, cm | 34.52 ± 3.11 | 33.81 ± 3.14a | 34.28 ± 3.22a | 34.68 ± 2.99b | 34.75 ± 3.12b | 0.001 |
| Body muscle mass, % | 25.24 ± 3.92 | 24.11 ± 3.48a | 24.70 ± 4.12a | 25.43 ± 3.69b | 26.23 ± 3.88c | 0.000 |
| Serum calcium, mmol/L | 2.42 ± 0.09 | 2.39 ± 0.10a | 2.41 ± 0.08b | 2.42 ± 0.09b | 2.43 ± 0.09c | 0.000 |
Data are shown as the mean ± standard deviation for continuous variables and n (%) for categorical variables. a-c Data in the same row with different superscript letters are significantly different from each other (P < 0.05; one‐way analysis of variance and Bonferroni test).