Table 1 Characteristics of the participants with serum 25(OH)D3 levels (n = 1667)
Variables | n % | 25(OH)D3(ng/mL) 1 | P value 2 |
|---|---|---|---|
Age | |||
16–17 | 31 (1.9) | 18.0 (15.7–20.1) | 0.32 |
18–19 | 1492 (89.5) | 17.0 (13.5–21.4) | |
20–26 | 144 (8.6) | 17.5 (14.3–22.4) | |
Gender | |||
Male | 383 (23.0) | 20.4 (15.9–25.5) |  < 0.001 |
Female | 1284 (77.0) | 16.2 (13.0–20.3) | |
Region of original residence | |||
City | 1072 (64.3) | 16.2 (13.1–20.7) |  < 0.001 |
Town | 197 (11.8) | 18.7 (14.3–22.9) | |
Countryside | 398 (23.9) | 18.4 (14.7–22.7) | |
Ethnicity | |||
The Han Ethnic | 1591 (95.4) | 17.1 (13.5–21.5) | 0.70 |
The Minorities | 76 (4.6) | 16.7 (13.6–19.9) | |
Taken calcium or vitamin D supplements within 3Â months | |||
Yes | 132 (7.9) | 18.8 (15.2–23.3) | 0.005 |
No | 1535 (92.1) | 17.0 (13.5–21.4) | |
Latitude | |||
18° N ~ 24° N | 37 (2.2) | 19.3 (14.2–26.3) | 0.07 |
25° N ~ 34° N | 1437 (86.2) | 17.0 (13.4–21.3) | |
35° N ~ 44° N | 176 (10.6) | 18.2 (14.4–21.8) | |
45° N ~ 49° N | 17 (1.0) | 17.6 (13.5–24.2) | |
Longitude | |||
76° E ~ 94° E | 36 (2.2) | 15.6 (12.9–18.7) |  < 0.001 |
95° E ~ 114° E | 241 (14.5) | 19.0 (15.2–23.1) | |
115° E ~ 131° E | 1390 (83.4) | 16.8 (13.3–21.2) | |
BMI categories3 | |||
 < 18.5 | 390 (23.4) | 16.3 (13.1–20.5) | 0.001 |
18.5 ~  < 24.0 | 906 (54.3) | 17.1 (13.6–21.2) | |
24.0 ~  < 28.0 | 225 (13.5) | 18.1 (14.1–23.1) | |
 ≥ 28.0 | 86 (5.2) | 18.0 (14.5–22.3) | |