Table 1.
Baseline characteristics of participants in the total population under different seasons.
| Variable | Spring (n = 5588) | Summer (n = 5905) | Autumn (n = 5435) | Winter (n = 5162) | P |
|---|---|---|---|---|---|
| Age(years) | 29 ± 4 | 29 ± 4 | 29 ± 4 | 29 ± 4 | 0.14* |
| 25(OH)D (nmol/L) | 35(28,48) | 48(35,63) | 48(35,63) | 23(30,43) | < 0.001^ |
| < 50 nmol/L | 4297 (76.9) | 3106 (52.6) | 2897 (53.3) | 4246 (82.3) | < 0.001# |
| 50 ~ 75 nmol/L | 1035 (18.5) | 2105 (35.6) | 1836 (33.8) | 752 (14.6) | |
| > 75 nmol/L | 256 (4.6) | 694 (11.8) | 702 (12.9) | 164 (3.2) | |
| Daily average temperature (°C) | 17 ± 5 | 28 ± 3 | 19 ± 5 | 7 ± 4 | < 0.001* |
| Daily total sunshine hours (h) | 5.1 ± 4.3 | 5.1 ± 4.3 | 4.2 ± 3.7 | 3.6 ± 3.6 | < 0.001* |
| Daily average pressure (hPa) | 1015 ± 6 | 1005 ± 3 | 1018 ± 6 | 1026 ± 5 | < 0.001* |
| Daily average relative humidity (%) | 70 ± 16 | 79 ± 12 | 78 ± 12 | 74 ± 14 | < 0.001* |
| Daily total precipitation (mm) | 3 ± 7 | 7 ± 18 | 4 ± 11 | 2 ± 5 | < 0.001* |
| Daily average wind speed (m/s) | 2.2 ± 0.8 | 2.1 ± 0.9 | 1.6 ± 0.7 | 1.9 ± 0.8 | < 0.001* |
25(OH)D, 25-hydroxyvitamin D.
#P was calculated used the chi-squared test.
^P was calculated used the Kruskal–Wallis test.
*P was calculated used the one-way ANOVA test.
P < 0.05 is considered statistically significance.
P-values indicate significant differences for the given parameter between the seasons.