Table 4.
Multivariable linear regression model for 91-day UV-B and square root transformed 25(OH)D within subgroups of age and physical activity index, weighted for the household population aged 12 to 79 years, Canada, 2007 to 2009
|
Effect Modifier |
β* ± SE |
Mean 25(OH)D** |
P |
Model |
Partial |
|---|---|---|---|---|---|
| (95% CI) | r2 | r2*** | |||
| Age |
|
|
|
|
|
| 12-19 years |
0.07 ± 0.01 |
0.9 (0.6, 1.3) |
< 0.0001 |
0.27 |
0.07 |
| 20-59 years |
0.04 ± 0.01 |
0.6 (0.3, 0.9) |
0.0001 |
0.22 |
0.03 |
| 60-79 years |
−0.01 ± 0.01 |
−0.1 (−0.5, 0.2) |
0.54 |
0.09 |
<0.01 |
| Physical Activity Index |
|
|
|
|
|
| Inactive |
0.03 ± 0.01 |
0.5 (0.0, 0.8) |
0.0009 |
0.20 |
0.02 |
| Moderately Active |
0.03 ± 0.01 |
0.4 (0.1, 0.8) |
0.02 |
0.19 |
0.01 |
| Active | 0.06 ± 0.02 | 0.9 (0.4, 1.3) | 0.0001 | 0.19 | 0.07 |
Adjusted for sex, age, ethnicity, sun exposure, vitamin D supplementation, milk consumption, BMI, and PAI.
*Estimated mean increase in square root transformed 25(OH)D for a 1 kJ/m2 increase in solar UV-B irradiance between 11 am and 4 pm at the CHMS collection sites averaged over the 91-days prior to blood draw (91-day UV-B).
**Estimated mean change in back transformed 25(OH)D (nmol/L) for a 1 kJ/m2 increase in solar UV-B irradiance between 11 am and 4 pm for the CHMS collection sites averaged over the 91-days prior to blood draw (91-day UV-B).
***Total variance in square root transformed 25(OH)D explained by 91-day UV-B, controlling for all other variables.