|  | Total N=1899
          n (%) | 
      
        | Outcome variables |  | 
      
        | RI    in the last 12 months | 691    (36.4%) | 
      
        | Wheezing    ever | 538    (28.3%) | 
      
        | Recent    Wheeze | 247    (13.0%) | 
      
        | Asthma    diagnosis | 131    (12.2%)a | 
      
        | Predictors |  | 
      
        | SHS    exposureb: |  | 
      
        | No | 1403    (73.9%) | 
      
        | In utero (maternal) | 50    (2.6%) | 
      
        | Current | 298    (15.7%) | 
      
        | Both in utero and current | 91    (4.8%) | 
      
        | THS    exposureb,c: |  | 
      
        | No | 1251    (83.4%) | 
      
        | Yes (≥1 per week) | 78    (5.2%) | 
      
        | Potential confounders |  | 
      
        | Age |  | 
      
        | < 6 years | 821    (43.2%) | 
      
        | ≥ 6 years | 1073    (56.5%) | 
      
        | Genderb |  | 
      
        | Male gender | 1018    (53.6%) | 
      
        | Female | 871(45.9%) | 
      
        | Gestational    ageb |  | 
      
        | <37 weeks | 114    (6.0%) | 
      
        | ≥37 weeks | 1736    (91.4%) | 
      
        | Complications    during pregnancy / birth |  | 
      
        | No | 1616    (85.1%) | 
      
        | Yes | 283    (14.9%) | 
      
        | Birth    weightb |  | 
      
        | Low birth weight (<2500g) | 100    (5.3%) | 
      
        | Normal birth weight (≥2500g) | 1701    (89.6%) | 
      
        | Breastfeedingb |  | 
      
        | No breastfeeding | 670    (35.3%) | 
      
        | <6 months | 688    (36.2%) | 
      
        | 6 – 12 months | 413    (21.7%) | 
      
        | > 12 months | 108    (5.7%) | 
      
        | Atopic    first degree relative |  | 
      
        | No | 587    (30.9%) | 
      
        | Yes | 1312    (69.1%) | 
      
        | Child    at high risk of asthmab |  | 
      
        | No | 1141    (60.1%) | 
      
        | Yes | 473    (24.9%) | 
      
        | Vitamin    D use: |  | 
      
        | Never | 1209    (63.7%) | 
      
        | Sometimes | 167    (8.8%) | 
      
        | Daily | 523    (27.5) | 
   
      
        |  | Total N=1899
          n (%) | 
      
        | Potential confounders cont. |  | 
      
        | ≥1 siblings |  | 
      
        | No | 530    (27.9%) | 
      
        | Yes | 1368    (72.0%) | 
      
        | Day    care attendance |  | 
      
        | No | 285    (15.0%) | 
      
        | Yes | 1614    (85.0%) | 
      
        | Highest    parental education |  | 
      
        | Low | 72    (3.8%) | 
      
        | Middle | 530    (27.9%) | 
      
        | High | 858    (45.2%) | 
      
        | Academic | 425    (22.4%) |