Table 1 Participant characteristics by study group
|  | Never Wheezers Never Asthmatics (NWNA) | Active Asthmatics (AA) | p-value †|
|---|---|---|---|
n = 671 | n = 69 | ||
Gender: Male | 42.8% | 43.5% | 0.91 |
Season of assessments | |||
  Autumn | 11.3% | 2.9% | 0.00 |
  Winter | 50.1% | 31.9% | |
  Spring | 38.6% | 65.2% | |
Parental education level | |||
  None/Primary | 3.0% | 7.2% | 0.14 |
  Secondary | 61.9% | 55.1% | |
  Tertiary | 35.2% | 37.7% | |
Sun exposure in the Summer | |||
  < 1 hour/day | 2.8% | 4.3% | 0.22 |
  1-2 hours/day | 15.8% | 7.2% | |
  2-3 hours/day | 25.9% | 23.2% | |
  3-4 hours/day | 24.8% | 24.6% | |
  >4 hours/day | 30.6% | 40.6% | |
Sun exposure in the Winter | |||
  < 1 hour/day | 21.6% | 15.9% | 0.55 |
  1-2 hours/day | 39.2% | 39.1% | |
  2-3 hours/day | 21.9% | 20.3% | |
  3-4 hours/day | 11.4% | 17.4% | |
  >4 hours/day | 6.0% | 7.2% | |
Sun protection | |||
  Never/Rarely | 24.7% | 24.6% | 0.47 |
  Occasionally | 37.2% | 39.1% | |
  Most of the times | 21.5% | 14.5% | |
  Always/Almost always | 16.6% | 21.7% | |
Skin type | |||
  Olive | 4.0% | 2.9% | 0.97 |
  Olive medium | 69.5% | 69.6% | |
  Medium fair | 25.0% | 26.1% | |
  Fair | 1.5% | 1.4% | |
Exercise level (IPAQ) | |||
  Low | 52.9% | 49.2% | 0.40 |
  Moderate | 34.0% | 41.5% | |
  High | 13.1% | 9.2% | |
Dietary intake vitamin D | |||
  <400 IU | 93.9% | 91.2% | 0.37 |
Family history of allergies | 19.4% | 49.3% | <0.01 |
Current smokers | 9.8% | 15.9% | 0.11 |
Age– Mean (SD) in years) | 17.0 (0.61) | 16.9 (0.57) | 0.63 |
Body fat percent – Mean (SD) | 22.0 (8.9) | 21.7(8.6) | 0.77 |