Table 3.
Proportion of variation explained (r 2) by environmental and genetic determinants for seasonally adjusted levels of vitamin D
| Factor | Seasonally adjusted only r 2 (%) | Adjusted r 2 (%) | Adjusted also with supplementation r 2 (%) | Seasonally adjusted only r 2 (%) | Adjusted r 2 (%) | Seasonally adjusted only r 2 (%) | Adjusted r 2 (%) |
|---|---|---|---|---|---|---|---|
| Cases | Controls | Cases + controls | |||||
| BMI | 1.0 | – | – | 2.1 | – | 1.3 | – |
| Sex | 0.06 | – | – | 0.2 | – | 0.02 | – |
| Age (per year) | 2.1 | – | – | 0.03 | – | 1.4 | – |
| Townsend | 0.5 | – | – | 0.3 | – | 0.6 | – |
| Case–control status | – | – | – | 1.0 | – | 0.7 | – |
| Supplementation | 7.0 | 6.0 | – | – | – | – | |
| Sun sensitivity index | 0.6 | 0.5 | 0.9 | 0.3 | 0.2 | 0.6 | 0.4 |
| Nevus number | 0.4 | 0.5 | 0.4 | 3.2 | 2.8 | 0.3 | 0.8 |
| Freckling total (%) | 0.9 | 0.8 | 0.9 | 4.0 | 4.8 | 1.3 | 1.4 |
| Freckling shoulders (%) | 1.9 | 2.0 | 1.9 | 5.7 | 6.2 | 2.4 | 2.7 |
| Sunscreen usage | 0.5 | 0.4 | 0.3 | 3.5 | 3.0 | 0.9 | 0.8 |
| Sun exposure** | – | 5.2 | 5.4 | – | 8.7 | – | 6.0 |
| Daily sun exposure* | 0.4 | 0.8 | 1.0 | 1.3 | 1.2 | 0.6 | 1.0 |
| Weekend sun exposure* | |||||||
| Overall* | 2.3 | 1.7 | 2.1 | 5.1 | 5.1 | 3.2 | 2.4 |
| Weekend exposure cooler months* | 1.4 | 1.1 | 1.1 | 1.7 | 1.9 | 1.7 | 1.4 |
| Weekend exposure warmer months* | 2.0 | 1.5 | 2.0 | 6.7 | 6.7 | 3.1 | 2.5 |
| Holiday exposure* | |||||||
| Overall* | 2.0 | 1.6 | 1.8 | 2.3 | 2.7 | 2.3 | 2.0 |
| Holiday exposure lower than 45o* | 3.6 | 3.7 | 3.6 | 2.4 | 2.5 | 3.2 | 3.3 |
| rs_2282679 | 3.9 | 4.0 | 4.9 | 2.6 | 1.8 | 3.3 | 3.1 |
| rs_7944926 | 0.6 | 0.9 | 1.0 | 1.2 | 1.1 | 0.5 | 0.6 |
| rs_10741657 | 0.7 | 0.9 | 0.8 | 2.3 | 2.4 | 0.4 | 0.5 |
Adjusted models were corrected for age, sex, case–control status, vitamin D supplementation(where appropriate), BMI, and Townsend score
* Corrected for sun sensitivity status in addition to season, age, sex, vitamin D supplementation, BMI, and Townsend score in multivariable models
** Model includes daily sun exposure, weekend sun exposure in warmer months, weekend sun exposure in cooler months, holiday sun exposure and holiday sun exposure at low latitudes and is also corrected for sun sensitivity